SEC Technical Report Summary

Pre-Feasibility Study

Mountain Pass Mine

San Bernardino County, California

Effective Date: October 1, 2023

Report Date: February 22, 2024

Report Prepared for

MP Materials Corp.

1700 S. Pavilion Center Dr.

Eighth Floor

Las Vegas, NV 89135

Report Prepared by

SRK Consulting (U.S.), Inc.

1125 Seventeenth Street, Suite 600

Denver, CO 80202

SRK Project Number: USPR001660

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 2

Table of Contents

1   Executive Summary	18
1.1  Property Description and Ownership	18
1.2  Geology and Mineralization	18
1.3  Status of Exploration, Development and Operations	19
1.4  Mineral Processing and Metallurgical Testing	19
1.4.1  Existing Crushing and Concentrating Operations	19
1.4.2  Rare Earths Separations	19
1.5  Mineral Resource Estimate	21
1.6  Mineral Reserve Estimate	23
1.7  Mining Methods	25
1.8  Recovery Methods	26
1.8.1  Existing Crushing and Concentrating Operations	26
1.8.2  Modified and Recommissioned Separations Facility	26
1.9  Project Infrastructure	26
1.10 Market Studies and Contracts	28
1.11 Environmental, Closure and Permitting	28
1.12 Capital and Operating Costs	29
1.12.1  Capital Costs	29
1.12.2  Operating Costs	29
1.13 Economic Analysis	30
1.14 Conclusions and Recommendations	31
2   Introduction	32
2.1  Registrant for Whom the Technical Report Summary was Prepared	32
2.2  Terms of Reference and Purpose of the Report	32
2.3  Sources of Information	32
2.4  Details of Inspection	32
2.5  Report Version Update	33
2.6  Units of Measure	33
2.7  Mineral Resource and Mineral Reserve Definitions	33
2.7.1  Mineral Resources	33
2.7.2  Mineral Reserves	34
2.8  Qualified Person	34
3   Property Description and Location	36
3.1  Property Location	38
3.2  Mineral Title	38

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3.2.1  Nature and Extent of Registrant’s Interest	41
3.3  Royalties, Agreements, and Encumbrances	41
3.4  Environmental Liabilities and Permitting	41
3.4.1  Remediation Liabilities	42
3.4.2  Required Permits and Status	42
3.5  Other Significant Factors and Risks	43
4   Accessibility, Climate, Local Resources, Infrastructure, and Physiography	44
4.1  Topography, Elevation, and Vegetation	44
4.2  Accessibility and Transportation to the Property	44
4.3  Climate and Length of Operating Season	44
4.4  Infrastructure Availability and Sources	45
5   History	46
5.1  Prior Ownership and Ownership Changes	46
5.2  Exploration and Development Results of Previous Owners	46
5.3  Historical Production	48
6   Geological Setting, Mineralization and Deposit	52
6.1  Regional Geology	52
6.2  Local and Property Geology	54
6.2.1  Local Lithology	56
6.2.2  Alteration	58
6.2.3  Structure	59
6.3  Significant Mineralized Zones	60
6.3.1  Bastnaesite Sövite	60
6.3.2  Bastnaesite Beforsite	61
6.3.3  Bastnaesite Dolosovite	61
6.3.4  White Sövite	62
6.3.5  Parisite Sövite	62
6.3.6  Monazitic Carbonatite	62
6.3.7  Breccia	63
6.4  Surrounding Rock Types	63
6.5  Relevant Geological Controls	64
6.6  Deposit Type, Character, and Distribution of Mineralization	64
7   Exploration and Drilling	65
7.1  Exploration	65
7.2  Drilling	65
8   Sample Preparation, Analysis and Security	67
8.1  Sampling	67

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8.1.1  Historical Sampling Procedures	67
8.1.2  Sampling 2009-2011	68
8.1.3  Sampling 2021	68
8.2  Laboratory Analysis	68
8.2.1  Note on Assay Terminology	69
8.2.2  Historical Analyses	69
8.2.3  Current Analytical Practices	69
8.2.4  2009 and 2010 Samples	70
8.2.5  2011 Samples	70
8.2.6  2021 Samples	71
8.3  Quality Control and Quality Assurance	71
8.3.1  Historical QA/QC	71
8.3.2  2009-2010 Campaign QA/QC Program	71
8.3.3  2011 Campaign QA/QC Program	73
8.3.4  2021 Campaign QA/QC Program	73
9   Data Verification	76
9.1  Re-Assaying Program	76
9.1.1  Procedures	76
9.1.2  SGS Check Assay Sample Preparation	77
9.1.3  SGS Check Assay XRF Procedures	77
9.1.4  Analysis of Light Rare Earth Oxide Distribution	77
9.1.5  Analysis of Heavy Rare Earth Oxide Assays	79
9.1.6  Results	80
9.2  Opinion on Data Adequacy	84
10  Mineral Processing and Metallurgical Testing	86
10.1 Background	86
10.2 Flotation Studies Versus Ore Grade	86
10.3 Concentrator Recovery Estimate	89
10.4 Separation of Individual Rare Earths	89
10.4.1  Metallurgical Testwork	90
10.4.2  Representativeness of Test Samples	92
10.4.3  Analytical Laboratories	93
10.4.4  Separations Facility Recovery Estimates	93
10.4.5  Expected Product Specifications	103
11  Mineral Resource Estimate	105
11.1 Topography and Coordinate System	105
11.2 Drillhole Database	105

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11.3 Geology	108
11.3.1  Structural Model	108
11.3.2  Lithology Model	109
11.3.3  Mineralogical / Alteration Model	110
11.4 Exploratory Data Analysis	111
11.4.1  Resource Domains	111
11.4.2  Outliers	113
11.4.3  Compositing	117
11.5 Bulk Density	117
11.6 Spatial Continuity Analysis	118
11.7 Block Model Limits	120
11.8 Grade Estimation	121
11.8.1  Blasthole Estimate Specifics	122
11.8.2  Exploration Estimate Specifics	122
11.9 Model Validation	123
11.10 Production Reconciliation	124
11.10.1 Blasthole “Bias”	127
11.11 Uncertainty and Resource Classification	130
11.12 Cut-Off Grade and Pit Optimization	131
11.13 Mineral Resource Statement	133
11.14 Mineral Resource Sensitivity	135
11.15 Assumptions, Parameters, and Methods	137
12  Mineral Reserve Estimate	139
12.1 Conversion Assumptions, Parameters, and Methods	139
12.1.1  Model Grade Dilution and Mining Recovery	140
12.1.2  Cut-Off Grade Calculation	140
12.2 Reserve Estimate	141
12.3 Relevant Factors	142
13  Mining Methods	144
13.1 Parameters Relevant to Mine or Pit Designs and Plans	145
13.1.1  Geotechnical	145
13.1.2  Hydrogeological	149
13.2 Pit Optimization	161
13.2.1  Mineral Resource Models	162
13.2.2  Topographic Data	162
13.2.3  Pit Optimization Constraints	162
13.2.4  Pit Optimization Parameters	163

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13.2.5  Optimization Process	164
13.2.6  Optimization Results	164
13.3 Design Criteria	167
13.3.1  Pit and Phase Designs	167
13.4 Mine Production Schedule	170
13.4.1  Mine Production	171
13.5 Waste and Stockpile Design	177
13.5.1  Waste Rock Storage Facility	177
13.5.2  Stockpiles	179
13.6 Mining Fleet and Requirements	179
13.6.1  General Requirements and Fleet Selection	179
13.6.2  Drilling and Blasting	182
13.6.3  Loading	182
13.6.4  Hauling	183
13.6.5  Auxiliary Equipment	184
13.6.6  Mining Operations and Maintenance Labor	185
14  Processing and Recovery Methods	187
14.1 Historic Production	187
14.2 Current Operations	187
14.2.1  Crushing	188
14.2.2  Grinding	188
14.2.3  Reagent Conditioning and Flotation	188
14.2.4  Sampling and Bagging	189
14.2.5  Paste Tailings Plant	189
14.2.6  Metallurgical Control and Accounting	189
14.2.7  Concentrator Performance	189
14.2.8  Significant Factors	192
14.3 Individual Rare Earth Separations	192
15  Infrastructure	196
15.1 Access and Local Communities	196
15.2 Site Facilities and Infrastructure	197
15.2.1  On-Site Facilities	197
15.2.2  Explosives Storage and Handling Facilities	198
15.2.3  Service Roads	198
15.2.4  Mine Operations and Support Facilities	198
15.2.5  Waste and Waste Handling (Non-Tailings/Waste Rock)	199
15.2.6  Waste Rock Handling	199

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15.2.7  Power Supply and Distribution	199
15.2.8  Natural Gas	199
15.2.9  Vehicle and Heavy Equipment Fuel	199
15.2.10 Other Energy	199
15.2.11 Water Supply	199
15.3 Tailings Management Area	201
15.4 Security	202
15.5 Communications	202
15.6 Logistics Requirements and Off-Site Infrastructure	202
15.6.1  Rail	202
15.6.2  Port and Logistics	202
16  Market Studies and Contracts	203
16.1 Abbreviations	203
16.2 Introduction	203
16.3 General Market Outlook	205
16.3.1  Historical Pricing	205
16.3.2  Market Balance	209
16.3.3  Costs	212
16.4 Products and Markets	213
16.4.1  Mineral Concentrate	213
16.4.2  PrNd Oxide	216
16.4.3  SEG+ Oxalate, Carbonate, Chloride and Oxide (SEG+ precipitate)	219
16.4.4  La Carbonate	221
16.4.5  Cerium Chloride	223
16.5 Specific Products	225
16.5.1  Concentrate	226
16.5.2  PrNd Oxide	227
16.5.3  SEG+ Precipitate	228
16.5.4  La Carbonate	228
16.5.5  Cerium Chloride	229
16.6 Conclusions	230
16.7 Contracts	230
17  Environmental Studies, Permitting, and Closure	233
17.1 Environmental Study Results	233
17.2 Required Permits and Status	233
17.3 Mine Closure	234
18  Capital and Operating Costs	235

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18.1 Capital Cost Estimates	235
18.1.1  Mining Capital Cost	235
18.1.2  Separations Facility Capital Cost	237
18.1.3  Other Sustaining Capital	237
18.1.4  Closure Costs	237
18.1.5  Basis for Capital Cost Estimates	237
18.2 Operating Cost Estimates	238
18.2.1  Mining Operating Cost	238
18.2.2  Processing Operating Cost	241
18.2.3  Selling, General, and Administrative Operating Costs	242
19  Economic Analysis	243
19.1 General Description	243
19.2 Basic Model Parameters	243
19.3 External Factors	243
19.3.1  Pricing	243
19.3.2  Taxes and Royalties	244
19.3.3  Working Capital	244
19.4 Technical Factors	244
19.4.1  Mining Profile	244
19.4.2  Processing Profile	245
19.4.3  Operating Costs	246
19.4.4  Mining	248
19.4.5  Processing	248
19.4.6  G&A Costs	248
19.4.7  Capital Costs	248
19.4.8  Results	249
19.4.9  Sensitivity Analysis	250
19.4.10  Physical and Cash Flow Snapshot	250
20  Adjacent Properties	252
21  Other Relevant Data and Information	253
22  Interpretation and Conclusions	254
22.1 Mineral Resource Estimate	254
22.2 Mineral Reserve Estimate	254
22.3 Metallurgy and Processing	256
22.3.1  Existing Crushing and Concentration Operations	256
22.3.2  Modified and Recommissioned Separations Facility	256
22.4 Project Infrastructure	256

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22.5 Products and Markets	257
22.6 Environmental, Closure, and Permitting	257
22.7 Projected Economic Outcomes	258
23  Recommendations	259
23.1 Geology and Resources	259
23.2 Mining and Reserves	260
23.2.1  Geotechnical Recommendations:	260
23.2.2  Hydrogeology:	260
23.2.3  Costs and Economics	260
24  References	261
25  Reliance on Information Provided by the Registrant	263
Signature Page	264

List of Tables

Table 1-1: Product Specifications	20
Table 1-2: Mineral Resource Statement Exclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2023	22
Table 1-3: Mineral Reserves at Mountain Pass as of September 30, 2023 - SRK Consulting (U.S.), Inc.	24
Table 1-4: Summary of Long-Term Price Forecasts	28
Table 1-5: LoM Capital Expenditures	29
Table 1-6: Operating Costs	29
Table 1-7: Cash Flow Summary	30
Table 2-1: Site Visits	33
Table 3-1: Current Financial Assurance Obligations	42
Table 5-1: Production History, 1952 to 1970	49
Table 5-2: Mine Production History, 1971 to 2002	50
Table 5-3: Mountain Pass Production History, 2009 to 2015, as Separated RE Products	50
Table 5-4: Mountain Pass Production History, 2018 to 2023, as Bastnaesite Concentrate	51
Table 8-1: Oxides and TREO Detection Limits, Mountain Pass Laboratory	70
Table 8-2: Oxides and Element Detection Limits, Actlabs Laboratory	71
Table 9-1: Oxides Analyzed with Detection Limits	77
Table 9-2: Light Rare Earth Oxide Distribution Statistics: 2009 and 2010 Analyses	78
Table 9-3: Light Rare Earth Oxide Distribution Statistics: 2011 Analyses	78
Table 9-4: Light Rare Earth Oxide Distribution Statistics: 2009, 2010 and 2011 Analyses	78
Table 9-5: Light Rare Earth Oxide Assay Statistics: 2009 and 2010 Analyses	79
Table 9-6: Heavy Rare Earth Summary	80

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Table 9-7: Standards with Expected Analytical Performance	80
Table 10-1: Head Analyses for Grade Range Test Composites	87
Table 10-2: Cumulative Rougher Flotation Concentrate Grade and Recovery Versus Ore Grade	87
Table 10-3: Estimated Rougher and Cleaner Flotation REO Recovery (1)	88
Table 10-4: Analytical Laboratories	93
Table 10-5: Feed Conditions that Resulted in Optimal Extractions at 109 g/L	95
Table 10-6: Test Material Feed Composition by % Solid REO	96
Table 10-7: Outlet Stream Composition by g/L REO at 109 g/L	96
Table 10-8: Settling Test Results Including Overflow Clarity with Various Flocculants and Dosages	96
Table 10-9: Assays of Feed, Cell of Complete Rare Earth Breakthrough, and Cell of Fe/U Bleed	98
Table 10-10: Mass Balance Calculations for Outlet Streams at Various Fractions	98
Table 10-11: Volumetric Flowrates of Different Streams along with Mass Flowrates of Different Components	100
Table 10-12: Impurities in Brine Before and After Treatment	103
Table 11-1: TREO Influence Limitations	114
Table 11-2: 2009 Specific Gravity Results - Carbonatite	118
Table 11-3: Block Model Specifications	120
Table 11-4: Blasthole vs. Exploration Comparison	128
Table 11-5: Cut-Off Grade Input Parameters	132
Table 11-6: Mineral Resource Statement Exclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2023	134
Table 11-7: Mineral Resources Inclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2023	135
Table 11-8: TREO Cut-off Sensitivity Analysis Within Resource Pit –Indicated Category	136
Table 11-9: TREO COG Sensitivity Analysis Within Resource Pit – Inferred Category	136
Table 11-10: Mineralized Material External to Resource Pit	137
Table 12-1: Pit Optimization Inputs	141
Table 12-2: Mineral Reserves at Mountain Pass as of September 30, 2023, SRK Consulting	142
Table 13-1: Recommended Slope Design Parameters	147
Table 13-2: CNI Final Recommended Slope Design Parameters by Design Sector	148
Table 13-3: Summary of Measured Hydraulic Conductivity Values	152
Table 13-4: Summary of Pit Water Production in the First Half of 2023	158
Table 13-5: Block Model Block Sizes	162
Table 13-6: Mountain Pass Pit Optimization Result Using Indicated Classification Only	165
Table 13-7: Estimated Remaining Storage Capacity for Waste Rock	178
Table 13-8: Mining Equipment Requirements	181
Table 13-9: Loading Statistics by Unit Type in Waste	182
Table 13-10: Loading Productivities by Unit Type in Waste	183

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Table 13-11: Hauling Statistics by Unit Type in Waste	183
Table 13-12: Pit Haulage Cycle Times (minutes)	184
Table 13-13: Mining Operations and Maintenance Labor Requirements	186
Table 14-1: Historic Mill Production, 1980 to 2002	187
Table 14-2: Concentrator Production Summary - 2022	191
Table 14-3: Concentrator Production Summary - 2023 (Jan-Sep)	191
Table 14-4: Product Specifications	192
Table 16-1: Abbreviations for Market Studies and Contracts	203
Table 16-2: Summary of U.S. Facilities Monitoring and Limiting P-levels	224
Table 16-3: Summary of Long-Term Price Forecasts	226
Table 17-1: Current Environmental Permits and Status	234
Table 18-1: Mining Equipment Capital Cost Estimate (US$000’s)	236
Table 18-2: Estimated Separations Facility Sustaining Capital Costs	237
Table 18-3: Mining Operating Costs	239
Table 18-4: Separations Operating Costs	242
Table 18-5: Summary of MP Materials Site G&A Operating Costs	242
Table 19-1: Basic Model Parameters	243
Table 19-2: LoM Mining Summary	245
Table 19-3: LoM Processing Profile	245
Table 19-4: Mining Cost Summary	248
Table 19-5: Processing Cost Summary	248
Table 19-6: G&A Cost Summary	248
Table 19-7: Economic Result	249
Table 25-1: Reliance on Information Provided by the Registrant	263

List of Figures

Figure 1-1: Final Pit Design and Site Layout	25
Figure 1-2: Project Cashflow	31
Figure 3-1: General Facility Arrangement (WGS84 Coordinate System)	37
Figure 3-2: Location Map	38
Figure 3-3: Land Tenure Map	40
Figure 6-1: Regional Geological Map	53
Figure 6-2: Generalized Geologic Map – Sulfide Queen Carbonatite	55
Figure 6-3: Schematic Cross Section (A-A’) of Sulfide Queen Carbonatite	56
Figure 6-4: Simplified Stratigraphic Column for the Mountain Pass Site	58
Figure 7-1: Drilling in MP Materials Pit Area	66

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Figure 8-1: 2009 Through 2010 Pit Standard Assays	72
Figure 8-2: 2009 Through 2010 Duplicates	73
Figure 8-3: 2021 Field Duplicate Analyses – MP Materials Lab	74
Figure 8-4: External Duplicate Analyses – MP vs. ALS	75
Figure 9-1: Results of Standard Analysis	81
Figure 9-2: Results of Pulp Duplicate Analysis	83
Figure 9-3: Results of Field Duplicate Analysis	84
Figure 10-1: TREO Rougher Flotation Recovery versus Concentrate Grade for Different Feed Grades	88
Figure 10-2: TREO Recovery to Cleaner Flotation Concentrate versus Feed Grade	89
Figure 10-3: Primary Processes for Stage 2 Operation	90
Figure 10-4: Recovery Estimates	94
Figure 10-5: Extraction of Rare Earth Oxides at 109 g/L with 93+% PrNd	95
Figure 10-6: Extraction of Rare Earth Oxides at 127 g/L	95
Figure 10-7: Volumes of Leach Liquor per Volume of Resin Required Before a Regeneration Cycle	98
Figure 10-8: Mass Balance	99
Figure 10-9: Diagram of the SXH Process	99
Figure 10-10: % REO in Feed, Raffinate, and Preg Liquor	101
Figure 10-11: TREO in Overflow Liquor Over Time vs Stoichiometric Feed Ratio and pH	102
Figure 10-12: Market Standard PrNd Oxide Specification and Mountain Pass Historical Results	104
Figure 11-1: Drilling Distribution near Mountain Pass Mine	106
Figure 11-2: Sample Length Histogram – Mineralized CBT	107
Figure 11-3: Geological Mapping and Fault Expressions – August 2021	108
Figure 11-4: Plan View of 3D Geological Model	110
Figure 11-5: Histogram of TREO% within CBT	111
Figure 11-6: Cross-Section Illustrating CBT Domains and TREO Grades	113
Figure 11-7: Log Probability Plot for TREO – HG Core	115
Figure 11-8: Log Probability Plot for TREO – Undifferentiated CBT	116
Figure 11-9: Example of Directional Variogram – Blastholes TREO	119
Figure 11-10: Example of Directional Variogram – Exploration TREO	120
Figure 11-11: Domain Boundary Analysis – HG Core Domain within CBT	121
Figure 11-12: Variable Orientation Surfaces for Estimation Orientation	122
Figure 11-13: NW-SE Cross-Section Showing Block Grades, Composite Grades, Resource Pit Outline	123
Figure 11-14: Swath Plot (NS Orientation) Comparison Between TREO Block Grades and Composite Grades	124
Figure 11-15: Spatial Comparison of MRE Grade Distribution with Blasthole Grade Distribution	125
Figure 11-16: Comparison of Resource and Grade Control Models	126
Figure 11-17: Previous Production Areas for Reconciliation Validation	128
Figure 11-18: Percent Difference BH/EXP Estimate	129

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Figure 11-19: Extents of Optimized Pit Shape Relative to Surface Topography	133
Figure 11-20: Mineralized Material >= 2.18% TREO and External to Resource Pit Shell	137
Figure 12-1: Side by Side Comparison Non-Diluted (Left) Block Model and Diluted (Right) Block Model	140
Figure 13-1: Final Pit Design and Site Layout	145
Figure 13-2: Recommended Double Bench IRA from CNI	146
Figure 13-3: Idealized Cross-Section Through Mine Area and Adjacent Valleys	149
Figure 13-4: Simplified Surface Geology	150
Figure 13-5: Conceptual Hydrologic Cross-Section	151
Figure 13-6: Measured Hydraulic Conductivity Values per Depth	152
Figure 13-7: Location of Monitoring Wells, Measured Water Table Elevation, and Direction of Groundwater Flow (as Q2 2023)	153
Figure 13-8: Location of Piezometers and Measured Water Levels in Pit Walls	155
Figure 13-9: Location of Industrial and Domestic Water Supply Wells and Mine Facilities	157
Figure 13-10: Location of Proposed Pumping and Monitoring Wells by CNI Shown in Plan-View	159
Figure 13-11: Location of Proposed Pumping and Monitoring Wells by CNI Shown on Cross-Section	160
Figure 13-12: Mountain Pass Pit by Pit Optimization Result	166
Figure 13-13: Mountain Pass Mineral Reserves Pit (Red Line) and Mineral Resources Shell (Magenta Line) Surface Intersection	167
Figure 13-14: Phase Design Locations	168
Figure 13-15: Reserve Starting Topography, September 30, 2023	169
Figure 13-16: Final Pit Design	170
Figure 13-17: Total Mined Material from the Open Pit (Ore and Waste)	172
Figure 13-18: Ore Mined from the Open Pit	172
Figure 13-19: Mined Ore Grade	173
Figure 13-20: Rehandled Material	173
Figure 13-21: Mill Concentrate Production	174
Figure 13-22: Mill Feed Grade	174
Figure 13-23: Number of Benches Mined	175
Figure 13-24: Haul Truck Cycle Time	175
Figure 13-25: Long-Term Ore Stockpile End of Period Balance	176
Figure 13-26: Final Pit Design and Waste Dump Locations	179
Figure 14-1: MP Materials Concentrator Flowsheet	188
Figure 14-2: Rare Earth Distribution in Flotation Concentrate	193
Figure 15-1: Facilities General Location	197
Figure 15-2: Water Supply System	200
Figure 15-3: Northwest Tailings Disposal Facility	201
Figure 16-1: Annual PrNd Oxide Price Volatility	205
Figure 16-2: PrNd Oxide Price History	207

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Figure 16-3: SEG Oxide Price History	208
Figure 16-4: La Oxide Price History	208
Figure 16-5: Ce Oxide Price History	209
Figure 16-6: Supply Gap Growth to Accelerate from Late-2020s without Prompt New Investment	210
Figure 16-7: Adamas Accelerated Supply Growth Scenario Envisages Moderately Balanced Market Until Early 2030s Before Deficit Growth Accelerates	210
Figure 16-8: Adamas Base Case PrNd Oxide Price and Market Balance Forecast	211
Figure 16-9: Rare Earth Market Balance Forecast	212
Figure 16-10: Mineral Concentrate Price Forecast	214
Figure 16-11: PrNd Oxide Price Forecast	217
Figure 16-12: SEG+ Precipitate Price Forecast	220
Figure 16-13: La Carbonate Price Forecast	222
Figure 16-14: Ce Chloride Price Forecast	224
Figure 18-1: Mining Unit Cost Profile	240
Figure 19-1: Mining Profile	244
Figure 19-2: Concentrate Production	246
Figure 19-3: Separations Production Profile	246
Figure 19-4: Annual Operating Costs	247
Figure 19-5: LoM Operating Costs	247
Figure 19-6: Capital Expenditure Profile	249
Figure 19-7: Annual Cash Flow	249
Figure 19-8: After-Tax Sensitivity Analysis	250
Figure 19-9: Mountain Pass Annual Physicals and Cashflow (US$ millions)	251

Appendices

Appendix A: Claims List

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SEC Technical Report Summary – Mountain Pass Mine	Page 15

List of Abbreviations

The US System for weights and units has been used throughout this report. Tons are reported in short tons of 2,000 lb, drilling and resource model dimensions and map scales are in feet (ft). All currency is in U.S. dollars (US$) unless otherwise stated.

The following abbreviations may be used in this report.

Abbreviation	Unit or Term
A	ampere
AA	atomic absorption
A/m2	amperes per square meter
amsl	meters above mean sea level
ANFO	ammonium nitrate fuel oil
AP	Action Plan
°C	degrees Centigrade
CCD	counter-current decantation
CIL	carbon-in-leach
cm	centimeter
cm2	square centimeter
cm3	cubic centimeter
cfm	cubic feet per minute
CHP	combined heat and power plant
COG	cut-off grade
ConfC	confidence code
CRec	core recovery
CSS	closed-side setting
CTW	calculated true width
CUP	Conditional Use Permit
°	degree (degrees)
dia.	diameter
EIR	Environmental Impact Report
EIS	Environmental Impact Statement
EMP	Environmental Management Plan
FA	fire assay
Factor of Safety	FoS
ft	foot (feet)
ft2	square foot (feet)
ft3	cubic foot (feet)
g	gram
gal	gallon
g/L	gram per liter
g-mol	gram-mole
gpm	gallons per minute
g/t	grams per metric tonne
ha	hectares
HDPE	Height Density Polyethylene
hp	horsepower
HREE	heavy rare earth elements
HRSG	heat recovery steam generators
HTW	horizontal true width
ICP	inductively coupled plasma
ID2	inverse-distance squared
ID3	inverse-distance cubed
IFC	International Finance Corporation
ILS	Intermediate Leach Solution
kA	kiloamperes
kg	kilograms

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 16

Abbreviation	Unit or Term
km	kilometer
km2	square kilometer
koz	thousand troy ounce
kt	thousand tonnes
kt/d	thousand tonnes per day
kt/y	thousand tonnes per year
kV	kilovolt
kW	kilowatt
kWh	kilowatt-hour
kWh/t	kilowatt-hour per metric tonne
L	liter
L/sec	liters per second
L/sec/m	liters per second per meter
lb	pound
LLDDP	Linear Low Density Polyethylene Plastic
LOI	Loss on Ignition
LoM	life-of-mine
LREE	light rare earth elements
LUS	Land Use Services
m	meter
m2	square meter
m3	cubic meter
mg/L	milligrams/liter
mL	milliliter
mm	millimeter
mm2	square millimeter
mm3	cubic millimeter
MME	Mine & Mill Engineering
Moz	million troy ounces
Million short tons	million short tons
mtw	measured true width
MW	million watts
m.y.	million years
NGO	non-governmental organization
NTU	nephelometric turbidity unit
oz	troy ounce
%	percent
PLC	Programmable Logic Controller
PLS	Pregnant Leach Solution
PMF	probable maximum flood
ppb	parts per billion
ppm	parts per million
QA/QC	Quality Assurance/Quality Control
RC	rotary circulation drilling
RCRA	Resource Conservation and Recovery Act
REE	rare earth elements
REO	rare earth oxide
RF	Revenue Factor
RO	reverse osmosis
RoM	Run-of-Mine
RQD	Rock Quality Description
SEC	U.S. Securities & Exchange Commission
sec	second
SG	specific gravity
SLS	spent leach solution
SPT	standard penetration testing
st	short ton (2,000 pounds)
SX	solvent extraction
SXD	solvent extraction didymium

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 17

Abbreviation	Unit or Term
SXH	solvent extraction heavies
SXI	solvent extraction impurities
t	tonne (metric tonne) (2,204.6 pounds)
t/h	tonnes per hour
t/d	tonnes per day
t/y	tonnes per year
TEM	technical economic model
TREO	total rare earth oxide
TSF	tailings storage facility
TSP	total suspended particulates
TVR	thermal vapor recompression
µm	micron or microns
V	volts
VFD	variable frequency drive
W	watt
XRD	x-ray diffraction
y	year
yd3	cubic yard

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 18

1 Executive Summary

This report was prepared as a pre-feasibility level Technical Report Summary in accordance with the Securities and Exchange Commission (“SEC”) S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305) for MP Materials Corp. (“MP Materials”) by SRK Consulting (U.S.), Inc. (“SRK”) on the Mountain Pass Mine (“Mountain Pass”).

Sections of this report pertaining to the rare earth element (REE) separations facility at Mountain Pass were authored by SGS North America Inc. (“SGS”). Portions of this report pertaining to products and markets, including long term price forecast for REE products, were authored by Adamas Intelligence Inc. (“Adamas”).

1.1 Property Description and Ownership

Mountain Pass is located in San Bernardino County, California, north of and adjacent to Interstate-15 (I-15), approximately 15 miles (mi) southwest of the California-Nevada state line and 30 mi northeast of Baker, California, at geographic coordinates 35°28’56”N latitude and 115°31’54”W longitude. This area is part of the historic Clark Mining District established in 1865. Mountain Pass is the only rare earth deposit identified within this district. The Project lies within portions of Sections 11, 12, 13, and 14 of Township 16 North, Range 14 East, San Bernardino Base and Meridian.

On November 17, 2020, pursuant to a merger agreement dated July 15, 2020, MP Mine Operations LLC (“MPMO”) and Secure Natural Resources LLC (“SNR”), the company that holds the mineral rights to the mine, were combined with Fortress Value Acquisition Corp., a special purpose acquisition company (“FVAC”) (the “Business Combination”). In connection with the Business Combination, MPMO and SNR became subsidiaries of FVAC, which was in turn renamed MP Materials Corp.

Mining claims and surface rights associated with the Project include:

• Patented claims with surface rights owned by MPMO and mineral rights held by SNR

• Unpatented lode and mineral claims held by SNR

• Surface ownership by MPMO and mineral rights controlled by the State of California

• Surface ownership by MPMO and mineral rights controlled by the U.S.

• Surface ownership by School District and mineral rights controlled by the U.S.

The rare earth mineralization at the Project is located within land either owned or leased by MP Materials.

1.2 Geology and Mineralization

The Mountain Pass deposit is a rare-earth-element-enriched carbonatite deposit, historically referred to as the Sulfide Queen orebody. The carbonatite and numerous other alkaline intrusives in the vicinity are hosted in Proterozoic gneissic rocks which have been altered through alkali metasomatism (fenitized) by the intrusive carbonatite dikes. Smaller dikes and breccia bodies surround the Sulfide Queen orebody which comprises several different types of carbonatite (sovite, beforsite, dolosolvite, and white sovite) which are interlayered within a relatively large carbonatite package. This is unique in terms of size of the concession, and globally significant in terms of its enrichment in rare-earth minerals.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 19

The southern part of the Sulfide Queen orebody strikes to the south-southeast and dips at 40° to the west-southwest; the northern part of the orebody strikes to the north-northeast and dips at some 40° to the west-north-west. Several post-mineralization faults result in slight offsets to the otherwise simple tabular/lensoid geometry. The total orebody strike length is approximately 2,750 feet (ft) and dip extent is 3,000 ft; true thickness of the more than 2.0% total rare earth oxide (TREO) grade zone ranges between 15 ft and 250 ft.

The main rare-earth-bearing mineral, bastnaesite, is present in all carbonatite subtypes, but in relatively lower concentrations in the breccias and the monazitic carbonatites which typically occur outside and proximal to the main orebody. Monazite and crocidolite (“blue ore” found on the hangingwall contact in the northern part of the orebody) are both considered deleterious in the processing plant. In some areas, post-mineral fault zones provide a conduit for water which results in localized hydration and oxidation of the fresh carbonatite. This weathering dissolves the calcite and dolomite gangue minerals, leaving behind elevated concentrations of bastnaesite with limonite, resulting in what is referred to as brown and black ore types, the most altered of which results in a loosely consolidated high grade bastnaesite sand. The altered ore types are mined, stockpiled separately, and blended to maintain target ore grades in the mill feed blend.

1.3 Status of Exploration, Development and Operations

The Mountain Pass mine is an active operating mine. The primary mineral of economic interest is bastnaesite. MP Materials mines ore from the open pit, transports the ore to a primary crushing/stockpile facility and transports the ore to the mill. At the mill, the crushed material is ground further with a ball mill and conveyed via a slurry pipeline to the flotation plant to separate the bastnaesite from the gangue minerals. The primary product of the flotation process is a bastnaesite concentrate, which is filtered and then transported to customers for sale. MP Materials has recently recommissioned a REE separations facility at Mountain Pass that allows MP Materials to produce four saleable REE products: praseodymium and neodymium (PrNd) oxide, samarium, europium, and gadolinium (SEG+) oxide, lanthanum (La) carbonate, and cerium (Ce) chloride. As the REE separations facility ramps up, it is expected that all or nearly all of bastnaesite concentrate will be processed on-site to produce the saleable REE products.

1.4 Mineral Processing and Metallurgical Testing

1.4.1 Existing Crushing and Concentrating Operations

During the later years of mining operations at Mountain Pass, the ore grade is expected to decline. To assess TREO (total rare earth oxide) recovery from lower grade ore, MP Materials conducted rougher flotation tests on ore samples over a grade range from 1.86 - 8.10% TREO using standard concentrator test conditions. Based on the results of this testwork, MP Materials has developed a mathematical relationship to estimate overall TREO recovery versus ore grade. This relationship has been used to estimate TREO recovery from lower grade ores later in the mine life.

1.4.2 Rare Earths Separations

MP Materials is currently ramping up separation facility operations to increase production of four marketable rare earth products (PrNd oxide, SEG+ oxalate, La carbonate/La oxide, and Ce chloride).

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 20

The specifications for the four products are shown in Table 1-1, with further discussion on the product specification provided in Section 14.3.

Table 1-1: Product Specifications

Product	Compound	w/w % TREO	Purity
PrNd Oxide	75% Nd2O3 + 25% Pr6O11 (+/-2%)	99%	99.5%+ PrNd/TREO
SEG+ Oxalate/Concentrate	-	25% to 45%	99% SEG+/TREO
Lanthanum Carbonate	La2(CO3)3 + La2O3	99%	99% La/TREO
Cerium Chloride	LaCeCl3	45%	85% Ce/TREO

Source: MP Materials, 2021

Note: w/w % is the weight concentration of the solution.

The work effort to develop the design criteria for the separation facility is briefly described below and is detailed in Section 10.4. Unit operations for the separation facility are described below.

Concentrate Drying and Roasting

Concentrate drying and roasting was practiced at Mountain Pass commencing in the mid 1960’s. Tonnage quantity roasting test work to confirm optimum operating parameters was conducted at Hazen Research. Studies involving the definition of specific leaching conditions were conducted at SGS Lakefield and at Mountain Pass facilities. These studies served to elucidate optimum operational conditions. Of major importance was the adjustment of roasting parameters such that leaching dissolved trivalent rare earths and left the majority of the cerium undissolved.

Leaching

Optimization studies to specify the most appropriate leaching parameters were conducted at several external laboratories and at MP Materials Cerium 96 leaching facility. MP Materials upgraded a small-scale onsite leaching pilot facility which provided superior temperature control so as to define the optimum leach facility operating conditions. The leaching operations produced an undissolved cerium concentrate and solubilized trivalent rare earths plus dissolved impurities.

Impurity Removal

Soluble impurities in the leach solution include iron, aluminum, uranium, calcium, magnesium, and other minor quantities of dissolved elements. The MP Materials solvent extraction system used for this duty has been successfully operated for a number of years.

SXH and SXD

The solvent extraction heavies (SXH) circuit makes a bulk separation of heavy rare earths and the solvent extraction didymium (SXD) circuit separates a PrNd stream. These circuits have been piloted and have been demonstrated to function as designed.

Brine Recovery, Treatment, Crystallizing

MP Materials has conducted several rounds of pilot studies taking appropriate mixtures of brine from previously operated facilities and solvent extraction (SX) pilot plant investigations to produce a representative brine. Past experience coupled with recent modeling work indicate that the system has sufficient capacity to handle anticipated feed volumetric changes.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 21

Conclusions

As with any extensive process modification effort, all possible contingencies may not be anticipated. However, based upon the project documentation provided, a site visit to the MP Materials installations at Mountain Pass, and conversations with MP Materials engineers who are directly involved with the ongoing ramp up operations, it is the opinion of SGS North America Inc. (SGS) that the Mountain Pass modification and modernization project has been performed in a professional manner.

1.5 Mineral Resource Estimate

The Mineral Resources are reported in accordance with the S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305). Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resource will be converted into Mineral Reserves. The Mineral Resource modelling and reporting was completed by SRK Consulting (U.S.) Inc.

The mineral resource estimate has been constrained by a geological model considering relevant rock types, structure, and mineralization envelopes as defined by TREO content within relevant geological features. This geological model is informed principally by diamond core drilling and multiple phases of geological mapping. Three-dimensional (3D) and sectional interpretation is based on the combination of these data and utilized in the Mountain Pass geological model which forms the basis for the mineral resource domaining.

The mineral resources at the Mountain Pass deposit have been classified in accordance with the S-K 1300 regulations and definitions. SRK has addressed uncertainty and risk at Mountain Pass through the application of classification categories. The classification parameters are defined by a combination of geological understanding, quality of drilling and analytical data, the average distance to composited drilling data, the number of drillholes used to inform block grades, and a geostatistical indicator of relative estimation quality (kriging efficiency). Bulk density is based on average density measurements collected from the various rock types, and carbonatite density in particular is supported by extensive mining and processing reconciliation data. The in situ mineral resources at Mountain Pass are classified into Indicated and Inferred mineral resources.

The mineral resources at Mountain Pass demonstrate reasonable prospects for economic extraction through the application of a cut-off grade (COG) and volumetric constraint within the economic pit shell. SRK has calculated a resources COG of 2.18% TREO based on engineering and economic assumptions as outlined in this TRS. Mineral resources have been constrained within an economic pit shell based on reserve input parameters. For mineral resources, a revenue factor of 1.0 is selected which corresponds to a break-even economic pit shell. SRK notes that the pit selected for mineral resources has been influenced by setbacks relative to critical infrastructure such as the tailing storage and the rare earth oxide (REO) concentrator.

The September 30, 2023, mineral resource statement is shown in Table 1-2.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 22

Table 1-2: Mineral Resource Statement Exclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2023

Category	Resource Type	Cut-Off TREO%	Mass (million short tons)	Average Value (%)
				TREO(1)	La2O3(2)	CeO2	Pr6O11	Nd2O3	Sm2O3
Indicated	Within the Reserve Pit	2.18	0.94	2.31	0.75	1.15	0.10	0.28	0.02
	Within the Resource Pit	2.18	0.50	3.56	1.16	1.77	0.15	0.43	0.03
Total Indicated		2.18	1.45	2.75	0.89	1.37	0.12	0.33	0.02
Inferred	Within the Reserve Pit	2.18	6.70	5.52	1.80	2.76	0.23	0.67	0.05
	Within the Resource Pit	2.18	2.40	3.74	1.22	1.86	0.16	0.45	0.03
Total Inferred		2.18	9.10	5.05	1.64	2.52	0.21	0.61	0.05

Source: SRK 2023

⁽¹⁾: TREO% represents the total of individually assayed light rare earth oxides on a 99.7% basis of total contained TREO, based on the historical site analyses.

⁽²⁾: Percentage of individual light rare earth oxides are based on the average ratios; La₂O₃ is calculated at a ratio of 32.6% grade of TREO% equivalent estimated grade, CeO₂ is calculated at a ratio of 49.9% of TREO% equivalent estimated grade, Pr₆O₁₁ is calculated at a ratio of 4.3% of TREO% equivalent estimated grade, Nd₂O₃ is calculated at a ratio of 12.1% of TREO% equivalent estimated grade, and Sm₂O₃ is calculated at a ratio of 0.90% of TREO% equivalent estimated grade. The sum of light rare earths averages 99.7%; the additional 0.3% cannot be accounted for based on the analyses available to date and has been discounted from this resource statement.

General Notes:

• Mineral Resources are reported exclusive of Mineral Reserves.

• Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resources estimated will be converted into Mineral Reserves estimate.

• Mineral Resource tonnage and contained metal have been rounded to reflect the accuracy of the estimate, any apparent errors are insignificant.

• Mineral Resource tonnage and grade are reported as diluted.

• The Mineral Resource model has been depleted for historical and forecast mining based on the September 30, 2023, pit topography.

• Pit optimization is based on an average TREO% equivalent concentrate price of US$12,461 per dry st of 60% TREO concentrate, average mining cost at the pit exit of US$1.70 per dry st mined plus US$0.068 per dry st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$78.94 per dry st ore milled, separations facility costs of US$1,551 per dry st of 60% TREO concentrate treated, freight of US$163 per st of dry product shipped, sustaining capital costs of US$30.48 per dry st of ore mined, and overall pit slope angles of 39° to 45° including ramps.

• The mineral resource statement reported herein only includes the rare earth elements cerium, lanthanum, neodymium, praseodymium, and samarium (often referred to as light rare earths). While other rare earth elements, often referred to as heavy rare earths, are present in the deposit, they are not accounted for in this estimate due to historic data limitations (see Section 9.1.5).

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 23

1.6 Mineral Reserve Estimate

SRK developed a life-of-mine (LoM) plan for the Mountain Pass operation in support of mineral reserves. MP Materials will operate an on-site separations facility at the Mountain Pass that will allow the Company to separate bastnaesite concentrate into four individual REO products for sale (PrNd oxide, SEG oxalate, La carbonate/La oxide, and Ce chloride). For economic modeling purposes, a combination of concentrate sales and separated product sales was assumed for Q4 2023 through Q4 2024 while the separations facility ramps up to full capacity. From 2025 onward, it was assumed that all concentrate will be fed to the separations facility. Forecast economic parameters are based on current cost performance for process, transportation, and administrative costs, as well as a first principles estimation of future mining costs. Forecast revenue from concentrate sales and individual separated product sales is based on a preliminary market study commissioned by MP Materials, as discussed in Section 16 of this report.

From this evaluation, pit optimization was performed based on an equivalent concentrate price of US$10,836 per dry short ton (st) of 60% TREO concentrate. The results of pit optimization guided the design and scheduling of the ultimate pit. SRK generated a cash flow model which indicated positive economics for the LoM plan, which provides the basis for the reserves. Reserves within the new ultimate pit are sequenced for the full 34-year LoM (Q4 2023 through 2056).

The costs used for pit optimization include estimated mining, processing, sustaining capital, transportation, and administrative costs, including an allocation of corporate costs.

Processing recovery for concentrate is variable based on a mathematical relationship to estimate overall TREO recovery versus ore grade. The calculated COG for the reserves is 2.43% TREO, which was applied to indicated blocks contained within an ultimate pit, the design of which was guided by economic pit optimization.

The optimized pit shell selected to guide final pit design was based on a combination of the revenue factor (RF) 0.70 pit (used on the north half of the deposit) and the RF 1.00 pit shell (used on the south half of the deposit). The inter-ramp angles (IRA) used for the mine design are based on operational-level geotechnical studies and range from 44° to 47°.

Measured resources in stockpiles were converted to proven reserves. Indicated pit resources were converted to probable reserves by applying the appropriate modifying factors, as described herein, to potential mining pit shapes created during the mine design process. Inferred resources present within the LoM reserves pit are treated as waste.

The mine design process results in in situ open pit probable mineral reserves of 28.1 million st with an average grade of 6.26% TREO. Additionally, there are 0.6 million st of proven mineral reserves in stockpiles with an average grade of 4.33% TREO. Table 1-3 presents the mineral reserve statement, as of September 30, 2023, for Mountain Pass (MP Materials’ mining engineers provided a September 30, 2023 topography as a reserve starting point). The reference point for the mineral reserves is ore delivered to the Mountain Pass concentrator.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 24

Table 1-3: Mineral Reserves at Mountain Pass as of September 30, 2023 - SRK Consulting (U.S.), Inc.

Category	Description	Run-of-Mine (RoM) Million Short Tons (dry)		TREO%		MY%		Concentrate Million Short Tons (dry)
Proven	Current Stockpiles		0.61		4.33		3.67		0.02
	In situ		--		-		-		-
	Proven Totals		0.61		4.33		3.67		0.02
Probable	Current Stockpiles		-		-		-		-
	In situ		28.08		6.26		6.62		1.86
	Probable Totals		28.08		6.26		6.62		1.86
Proven + Probable	Current Stockpiles		0.61		4.33		3.67		0.02
	In situ		28.08		6.26		6.62		1.86
	Proven + Probable Totals		28.69		6.22		6.56		1.88

Source: SRK, 2023

General Notes:

• Reserves stated as contained within an economically minable open pit design stated above a 2.43% TREO COG.

• Mineral reserves tonnage and contained metal have been rounded to reflect the accuracy of the estimate, and numbers may not add due to rounding.

• MY% calculation is based on 60% concentrate grade of the product and the ore grade dependent metallurgical recovery. MY% = (TREO% * Met recovery)/60% concentrate TREO grade.

• Indicated mineral resources have been converted to Probable reserves. Measured mineral resources have been converted to Proven reserves.

• Reserves are diluted at the contact of the 2% TREO geological model triangulation (further to dilution inherent to the resource model and assume selective mining unit of 15 ft x 15 ft x 30 ft).Mineral reserves tonnage and grade are reported as diluted.

• Pit optimization is based on an average TREO% equivalent concentrate price of US$10,836 per dry st of 60% TREO concentrate, average mining cost at the pit exit of US$1.70 per dry st mined plus US$0.068 per dry st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$78.94 per dry st ore milled, separations facility costs of US$1,551 per dry st of 60% TREO concentrate treated, freight of US$163 per st of dry product shipped, sustaining capital costs of US$30.48 per dry st of ore mined, and overall pit slope angles of 39° to 45° including ramps..

• The topography used was from September 30, 2023.

• Reserves contain material inside and outside permitted mining but within mineral lease.

• Reserves assume 100% mining recovery.

• The strip ratio was 6.3 to 1 (waste to ore ratio).

• The mineral reserves were estimated by SRK Consulting (U.S.) Inc.

In the opinion of SRK as the QP, the conversion of mineral resources to mineral reserves has been completed in accordance with CFR 17, Part 229 (S-K 1300).

The reserve estimate herein is subject to potential change based on changes to the forward-looking cost and revenue assumptions utilized in this study. It is assumed that MP Materials will ramp up its on-site separations facilities to full capacity by the end of 2024. For economic modeling purposes, a combination of concentrate sales and separated product sales was assumed for Q4 2023 through Q4 2024. From 2025 onward, it was assumed that all concentrate will be fed to the separations facility.

Full extraction of this reserve is dependent upon modification of current permitted boundaries for the open pit. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the resource pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit would only include waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume MP Materials will be able to negotiate a similar agreement.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 25

1.7 Mining Methods

Mountain Pass is currently being mined using conventional open-pit methods. The open pit is in gently undulating topography intersecting natural drainages that require diversion to withstand some rainfall events during the summer and winter months. Waste dumps are managed according to the Action Plan (AP), are located on high ground, and are designed for control of drainage (contact water) if required.

The open pit that forms the basis of the mineral reserves and the LoM production schedule is approximately 3,100 ft from east to west and 3,800 ft from north to south with a maximum depth of 1,400 ft. Total pit mining is estimated at 203.9 million st comprised of 28.1 million st of ore and 175.8 million st of waste, resulting in a strip ratio of 6.3 (waste to ore). Additional mill feed is sourced from existing stockpiles (0.6 million st). LoM mill feed grade averages 6.22% TREO yielding over 1.88 million dry st of recoverable 60% TREO concentrate.

SRK designed four pit pushbacks that adhere to proper minimum mining widths. Bench sinking rates are approximated to no more than six benches per year per pushback.

Figure 1-1 illustrates the site layout and final pit design.

Source SRK, 2023

Figure 1-1: Final Pit Design and Site Layout

Mine activities include drilling, blasting, loading, hauling, and mining support activities. Drill and blast operations are performed by a contractor, and this will continue for the foreseeable future. All other mine operations are performed by MP Materials. The primary loading equipment is front-end loaders (15 cubic yards (yd³)), which were selected for operational flexibility. Rigid frame haul trucks with 102 wet short tons (wst) capacity were selected to match with the loading units.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 26

Material within the pit will be blasted on 30 ft high benches. Material classified as reserves will be sent to the RoM stockpiles for near-term blending to the primary crusher or, alternatively, to long-term stockpiles for processing later in the mine life. Waste dumps will be used for material below the cut-off grade.

The mine operations schedule includes one 12-hour day shift, seven days per week for 365 days per year.

1.8 Recovery Methods

1.8.1 Existing Crushing and Concentrating Operations

MP Materials operates a 2,000 t/d flotation concentrator that produces concentrates that are further processed to produce separated rare earth oxides. The concentrator flowsheet includes crushing, grinding, rougher/scavenger flotation, cleaner flotation, concentrate thickening and filtration and tailings thickening and filtration followed by dry stack tailings disposal. Significant improvements in concentrator performance have occurred since inception of operations, which are attributed primarily to new reagent and ore blending schemes as well as the introduction of steam to heat the flotation slurry. During 2022 TREO recovery averaged 65.3% into concentrates containing an average of 61.3% TREO. During 2023 (January – September) TREO recovery has averaged 64.0% into concentrates averaging 61.9% TREO.

1.8.2 Modified and Recommissioned Separations Facility

MP Materials is in the process of ramping up its modified and recommissioned on-site separations facility to produce individual rare earth products as summarized in Table 1-3. The incentive for this substantial process change is the enhancement of revenue that will be realized for producing individual rare earth products as compared to the previous practice of producing a single rare earth containing flotation concentrate which was sold to various entities that separate and market individual rare earth products. Over the past several years, MP Materials has made substantial technical and financial commitments to modify and recommission an on-site separation facility that will allow for the sale of individual rare earth products.

Consequently, based upon the project documentation provided, a site visit to the MP Materials installations at Mountain Pass, and conversations with MP Materials engineers who are directly involved with the ongoing ramp up operations, it is the opinion of SGS North America Inc. (SGS) that the Mountain Pass modification and modernization project has been performed in a professional manner. It is SGS’s further opinion that the ramp up schedule assumed for economic modeling purposes, which estimated feeding 20% and 61.25% of concentrate production into the facility in Q4 2023 and full year 2024, respectively, is likely to be achieved. From 2025 onward, the separations facility is likely to operate at full capacity thereby consuming all or nearly all of the bastnaesite flotation concentrate produced on site.

1.9 Project Infrastructure

The Project is in San Bernardino County, California, north of and adjacent to Interstate 15 (I-15), approximately 15 mi southwest of the California-Nevada state line and 30 mi northeast of Baker, California (Figure 3-2).

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The nearest major city is Las Vegas, Nevada, located 50 mi to the east on I-15. The Project lies immediately north of I-15 at Mountain Pass and is accessed by the Bailey Road Exit (Exit 281 of I-15), which leads directly to the main gate. The mine is approximately 15 mi southwest of the California-Nevada state line in an otherwise undeveloped area, enclosed by surrounding natural topographic features.

Outside services include industrial maintenance contractors, equipment suppliers and general service contractors. Access to qualified contractors and suppliers is excellent due to the proximity of population centers such as Las Vegas, Nevada as well as Elko, Nevada (an established large mining district) and Phoenix, Arizona (servicing the copper mining industry).

Access to the site, as well as site haul roads and other minor roads are fully developed and controlled by MP Materials. There is no public access through the Project area. All public access roads that lead to the Project are gated at the property boundary.

MP Materials has fully developed an operating infrastructure for the Project in support of mining, concentrating and separations activities. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

Substantially all the power to the Mountain Pass facility is currently supplied by a Combined Heat and Power (CHP) or co-generation (cogen) power facility with two natural gas-fired turbines capable of producing up to 26 MW of power combined. In addition, the site is served by a 12-kV line from a Southern California Edison substation two miles away.

Water is supplied through active water wells located eight miles west of the project. Fire systems are supplied by separate fire water tanks and pumps.

The site has all facilities required for operation, including the open pit, concentrator, separations facility, access and haul roads, explosives storage, fuel tanks and fueling systems, warehouse, security guard house and perimeter fencing, tailings filter plant, tailings storage area, waste rock storage area, administrative and office buildings, surface water control systems, evaporation ponds, miscellaneous shops, truck shop, laboratory, multiple laydown areas, power supply, water supply, waste handling bins and temporary storage locations, and a fully developed communications system.

The LoM plan will require the relocation in 2035 of the paste tailings plant and the water tanks currently located northeast of the pit highwall near the concentration plant. Additionally, the crusher will be relocated in 2028 to allow the pit to expand to the north. Capital cost provisions are included in the technical economic model (TEM) for these relocations.

The design capacity of the tailings storage facility is approximately 24 million st. The project has utilized approximately 4.2 million st of that space. The existing facility will have a remaining capacity of approximately 19.8 million st which will provide approximately 24 years of storage. MP Materials will expand the existing tailings facility to the northwest in approximately 2047 to provide an additional 9 years of storage capacity. A capital cost provision has been included in the TEM for this expansion.

Site logistics are straightforward with the concentrate product shipped in supersacks within a shipping container by truck to the port of Los Angeles. At the port, the containers are loaded onto a container ship and shipped to the final customers. Refined products for domestic customers are shipped in supersacks and intermediate bulk containers (IBC tote).

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1.10 Market Studies and Contracts

Section 16 of this report provides an overview of key trends within the rare earths market. Analysis outlined in this report reveals a high degree of variability in the demand profiles of individual rare earth elements and their associated end-uses.

Consequently, a strong demand outlook for PrNd oxide – the main rare earth input for neodymium iron boron (NdFeB) permanent magnets - drives a weak supply outlook for Ce and La products, which are sacrificially overproduced as a function of keeping up with magnet demand.

While centered in China, the rare earths market is increasingly global with suppliers and potential suppliers emerging around the world. Section 16 of this report highlights the favorable demand conditions that non-China producers may face as they enter the market but also highlights the unfavorable supply side conditions end users can expect without prompt new investment into new production.

Products outlined in this report (PrNd oxide, SEG+ precipitate, La carbonate, Ce chloride and rare earth mineral concentrate) are desirable from a market perspective, provided market standards and requirements are met. As shown in Table 1-4, and based on outlined product specifications, Adamas forecasts a long-term price of US$131.6/kg REO for PrNd oxide, US$51.90/kg REO for SEG+ oxalate, US$1.5/kg REO for Lanthanum carbonate, and US$2.51/kg REO for Cerium chloride. The mixed rare earth concentrate price of US$10.94/kg of contained REO will be principally driven by trends in PrNd and dysprosium (Dy), price swings of which will be mirrored by concentrates.

Table 1-4: Summary of Long-Term Price Forecasts

Product	Long-Term Price Forecast, Real 2023  US$/KG
Rare Earth Mineral Concentrate	US$10.94
PrNd Oxide	US$131.60
SEG+ Precipitate	US$51.90
La Carbonate	US$1.50
Ce Chloride	US$2.51

Source: Adamas, 2023

Many of the near-term risks facing players in the rare earths market are political, with past disputes responsible for exacerbating volatility of REE prices. Specific risks to products are highlighted where perceived, though the indicated specifications and communicated sales terms enforce the conclusion that products are both desirable and marketable.

1.11 Environmental, Closure and Permitting

As of September 30, 2023, MP Materials holds the necessary operating permits, including conditional use and minor use permits from the County of San Bernardino (SBC), which currently allows continued operations of the Mountain Pass facility through 2042.

MP Materials maintains financial assurance cost estimates for closure, post-closure maintenance (PCM), and All Known and Reasonably Foreseeable Releases (AKRFR) for current and planned operations at the Mountain Pass property. The Lahontan Regional Water Quality Control Board (LRWQCB) administers the groundwater and surface water related financial assurance obligations. The SBC administers financial assurance requirements for surface reclamation of the property. The California Department of Health, Radiological Health Branch administers financial assurance requirements for decontamination and decommissioning activities. MP Materials maintains

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miscellaneous financial assurance instruments for other closure-related obligations. As of September 2023, the total financial assurance obligation is approximately US$45.4 million.

1.12 Capital and Operating Costs

Capital and operating costs are incurred and reported in US dollars and are estimated at a pre-feasibility level with an accuracy of approximately +/-25%.

1.12.1 Capital Costs

The mine is currently operating and, as such, there is no initial capital expenditure required. All capital expenditure as contemplated by this report is expected to be sustaining capital. Sustaining capital expenditures include the sustaining capital cost associated with the mining fleet. Also included are sustaining capital cost provisions for the separations facility, planned paste tailings plant, crusher and water tank relocations, tailings storage facility expansion, and the “other” category, which captures all other sustaining capital costs.

Capital costs for the separations facility have been reviewed and approved by SGS. All other capital costs have been reviewed and approved by SRK.

Table 1-5 summarizes the LoM capital costs for Mountain Pass.

Table 1-5: LoM Capital Expenditures

Category	Years Incurred		LoM Total (US$ million)
Mining Equipment Replacements and Rebuilds		2024-2054		72.8
Infrastructure Relocations		2028 and 2035		78.7
TSF Expansion		2047		11.3
Closure		2057		45.4
Separations Facility Sustaining		2024-2056		537.9
Other Sustaining		2023-2056		109.8
Total				855.9

Source: SRK and SGS

1.12.2 Operating Costs

For economic modeling, the operating costs are allocated among three main areas: mining, processing and site general and administrative (G&A). SRK developed a first principles operating cost forecast for mining. SGS and MP Materials developed a first principles operating cost forecast for the separations facility. Otherwise, costs are forecast based on current operating results, with appropriate adjustments for anticipated future changes in the configuration of the operation.

The estimated operating costs are presented in Table 1-6.

Table 1-6: Operating Costs

Category	LoM Total (US$ million)		Average Unit Cost (US$/st ore processed)
Mining		663.8		23.1
Processing (including separations)		4,401.4		153.4
Site G&A		706.4		24.6
Total		5,771.6		201.2

Source: SRK and SGS

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1.13 Economic Analysis

SRK generated an economic model for the life of the reserve stated in this report. The economic model utilized the capital and operating costs described in Section 18. Product sales price assumptions are described in Section 16 and are based on a preliminary market study. Based on this economic analysis, the reserve stated herein generates positive free cash flow and meets the economic test for the declaration of a reserve under SEC regulations.

Economic analysis, including estimation of capital and operating costs is inherently a forward-looking exercise. These estimates rely upon a range of assumptions and forecasts that are subject to change depending upon macroeconomic conditions, operating strategy and new data collected through future operations and therefore actual economic outcomes often deviate significantly from forecasts.

The Mountain Pass operation consists of an open pit mine and processing facilities fed by the open pit mine. The operation is expected to have a 34-year life with the first modeled year of operation a partial year to align with the effective date of the reserves. The final years (2049 through 2056) are limited to the processing of remaining stockpiles.

The economic analysis metrics are prepared on an annual after-tax basis in US$. The results of the analysis are presented in Table 1-7. The results indicate that, at prices outlined in the market study section of this report, the operation returns an after-tax net present value (NPV) at 6% of US$5.2 billion. Note that because the mine is in operation and is valued on a total project basis with prior costs treated as sunk, internal rate of return (IRR) and payback period analysis are not relevant metrics.

Table 1-7: Cash Flow Summary

LoM Cash Flow (Unfinanced)	Units	Value
Total Revenue	US$ (million)		20,040
Total Opex	US$ (million)		(5,772	)
Operating Margin	US$ (million)		14,268
Operating Margin Ratio	%		71%
Taxes Paid	US$ (million)		(3,638)
Before Tax
Free Cash Flow	US$ (million)		13,412
NPV at 6%	US$ (million)		6,998
After Tax
Free Cash Flow	US$ (million)		9,775
NPV at 6%	US$ (million)		5,193

Source: SRK

A summary of the cashflow on an annual basis is presented in Figure 1-2.

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Source: SRK

Figure 1-2: Project Cashflow

1.14 Conclusions and Recommendations

Based on the data available and the analysis described in this report, in SRK’s opinion, the Mountain Pass operation has a valid mineral resource and mineral reserve, as stated herein. The resource estimation has been validated using conventional means and reconciled against production records.

The resources and reserves are subject to potential change based on changes to the forward-looking cost and revenue assumptions utilized in this study. Rare earth concentrate sales to China are currently subject to value added tax (VAT). Sales of individual rare earth products are assumed to begin in Q4 2023, with the separations facility ramping up to full capacity by the end of 2024.

Full extraction of this reserve is dependent upon modification of current permitted boundaries. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit only includes waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume that MP Materials will be able to negotiate a similar agreement.

Additional opportunity exists for the potential to convert current inferred resources both within the LoM pit and on the fringes of the pit. The conversion of inferred resources to either measured or indicated resources, if successful, would increase the mine life and reduce waste stripping. Therefore, SRK recommends that MP Materials target infill drilling for the purpose of this conversion.

Other, more minor recommendations are detailed in Section 23.

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2 Introduction

2.1 Registrant for Whom the Technical Report Summary was Prepared

This report was prepared as a pre-feasibility level Technical Report Summary in accordance with the Securities and Exchange Commission (SEC) S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305) for MP Materials Corp. (MP Materials) by SRK Consulting (U.S.), Inc. (SRK) on the Mountain Pass Mine (Mountain Pass).

2.2 Terms of Reference and Purpose of the Report

The quality of information, conclusions, and estimates contained herein are consistent with the level of effort involved in SRK’s services, based on: i) information available at the time of preparation and ii) the assumptions, conditions, and qualifications set forth in this report. This Technical Report Summary is based on pre-feasibility level engineering and cost estimation.

This report is intended for use by MP Materials subject to the terms and conditions of its contract with SRK and relevant securities legislation. The contract permits MP Materials to file this report as a Technical Report Summary with U.S. securities regulatory authorities pursuant to the SEC S-K regulations, more specifically Title 17, Subpart 229.600, Item 601(b)(96) - Technical Report Summary and Title 17, Subpart 229.1300 - Disclosure by Registrants Engaged in Mining Operations. Except for the purposes legislated under U.S. securities law, any other uses of this report by any third party are at that party’s sole risk. The responsibility for this disclosure remains with MP Materials.

The purpose of this Technical Report Summary is to report mineral resources and mineral reserves.

2.3 Sources of Information

This report is based in part on internal Company technical reports, previous engineering studies, maps, published government reports, Company letters and memoranda, and public information as cited throughout this report and listed in Section 24 of this report.

Reliance upon information provided by the registrant is listed in Section 25 when applicable.

2.4 Details of Inspection

Table 2-1 summarizes the details of the personal inspections on the property by each qualified person or, if applicable, the reason why a personal inspection has not been completed.

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Table 2-1: Site Visits

Expertise	Company	Date(s) of Visit	Details of Inspection
Infrastructure	SRK Consulting  (U.S.), Inc.	September 11 and September 25, 2023	Infrastructure, tailings area, general site inspection
Slope Stability/ Engineering Geology	SRK Consulting (U.S.), Inc.	September 25, 2019	Open pit slopes and stockpiles
Mining/Reserves	SRK Consulting (U.S.), Inc.	September 11, 2023	Review of the current practices and inspection
Geology/Mineral Resources	SRK Consulting (U.S.), Inc.	September 11, 2023	Review of the current practices and inspection of laboratory and core facility, tour of pit geology, meetings and technical sessions on geological modeling.
Metallurgy/ Process	SRK Consulting (U.S.), Inc.	September 25, 2023	Review of the current practices and inspection
Separations Facility	SGS North America Inc.	September 25, 2023	Review of construction and commissioning progress
Environmental/ Permitting/Closure	SRK Consulting (U.S.), Inc.	No recent site visit	Visited site on several occasions under previous ownership

Source: SRK, 2023

2.5 Report Version Update

The user of this document should ensure that this is the most recent Technical Report Summary for the property.

This Technical Report Summary is an update of a previously filed technical report summary filed pursuant to 17 CFR §§ 229.1300 through 229.1305 (subpart 229.1300 of Regulation S-K). The previously filed technical report summary is titled “SEC Technical Report Summary Pre-Feasibility Study Mountain Pass Mine San Bernardino County, California” with an effective date of September 30, 2021 and a report date of February 16, 2022.

2.6 Units of Measure

The U.S. System for weights and units has been used throughout this report. Tons are reported in short tons (st) of 2,000 lb, drilling and resource model dimensions and map scales are in feet (ft). All currency is in U.S. dollars (US$) unless otherwise stated.

2.7 Mineral Resource and Mineral Reserve Definitions

The terms “mineral resource” and “mineral reserves” as used in this Technical Report Summary have the following definitions as per the SEC, Regulation S-K, Item 1301.

2.7.1 Mineral Resources

17 CFR § 229.1300 defines a “mineral resource” as a concentration or occurrence of material of economic interest in or on the Earth’s crust in such form, grade or quality, and quantity that there are reasonable prospects for economic extraction. A mineral resource is a reasonable estimate of mineralization, taking into account relevant factors such as cut-off grade, likely mining dimensions, location or continuity, that, with the assumed and justifiable technical and economic conditions, is likely to, in whole or in part, become economically extractable. It is not merely an inventory of all mineralization drilled or sampled.

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A “measured mineral resource” is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of conclusive geological evidence and sampling. The level of geological certainty associated with a measured mineral resource is sufficient to allow a qualified person to apply modifying factors, as defined in this section, in sufficient detail to support detailed mine planning and final evaluation of the economic viability of the deposit. Because a measured mineral resource has a higher level of confidence than the level of confidence of either an indicated mineral resource or an inferred mineral resource, a measured mineral resource may be converted to a proven mineral reserve or to a probable mineral reserve.

An “indicated mineral resource” is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of adequate geological evidence and sampling. The level of geological certainty associated with an indicated mineral resource is sufficient to allow a qualified person to apply modifying factors in sufficient detail to support mine planning and evaluation of the economic viability of the deposit. Because an indicated mineral resource has a lower level of confidence than the level of confidence of a measured mineral resource, an indicated mineral resource may only be converted to a probable mineral reserve.

An “inferred mineral resource” is that part of a mineral resource for which quantity and grade or quality are estimated on the basis of limited geological evidence and sampling. The level of geological uncertainty associated with an inferred mineral resource is too high to apply relevant technical and economic factors likely to influence the prospects of economic extraction in a manner useful for evaluation of economic viability. Because an inferred mineral resource has the lowest level of geological confidence of all mineral resources, which prevents the application of the modifying factors in a manner useful for evaluation of economic viability, an inferred mineral resource may not be considered when assessing the economic viability of a mining project, and may not be converted to a mineral reserve.

2.7.2 Mineral Reserves

17 CFR § 229.1300 defines a “mineral reserve” as an estimate of tonnage and grade or quality of indicated and measured mineral resources that, in the opinion of the qualified person, can be the basis of an economically viable project. More specifically, it is the economically mineable part of a measured or indicated mineral resource, which includes diluting materials and allowances for losses that may occur when the material is mined or extracted. A “proven mineral reserve” is the economically mineable part of a measured mineral resource and can only result from conversion of a measured mineral resource. A “probable mineral reserve” is the economically mineable part of an indicated and, in some cases, a measured mineral resource.

2.8 Qualified Person

This report was compiled by SRK Consulting (U.S.), Inc., with contributions from SGS North America Inc. (SGS) and Adamas Intelligence Inc. (Adamas). All three firms are third-party firms comprising mining experts in accordance with 17 CFR § 229.1302(b)(1). MP Materials has determined that all three firms meet the qualifications specified under the definition of qualified person in 17 CFR § 229.1300.

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SGS North America Inc. prepared the following sections of the report.

• Sections 1.4.2 and 1.8.2 (Separations Facility)

• Section 1.12 (Separations Facility Capital and Operating Cost)

• Section 10.4 (Separation of Rare Earth Elements)

• Section 14.3 (Individual Rare Earths Separations)

• Sections 18.1.2 and 18.1.5 (Separations Facility Capital Cost)

• Section 18.2.2 (Separations Facility Operating Cost)

• Section 22.3.2 (Separations Facility)

• Section 22.5 (Products and Markets)

• Related contributions to Section 1 (Executive Summary), Section 23 (Recommendations), Section 24 (References), Section 25 (Reliance on Information Provided by the Registrant )

In sections of this report prepared by SGS, references to the Qualified Person or QP are references to SGS North America Inc. and not to any individual employed at SGS.

Adamas Intelligence Inc. prepared the following sections of the report.

• Section 16 (Market Studies and Contracts)

• Related contributions to Section 1 (Executive Summary), Section 22 (Interpretations and Conclusions), Section 23 (Recommendations) and Section 24 (References) and Section 25 (Reliance on Information Provided by the Registrant)

In sections of this report prepared by Adamas, references to the Qualified Person or QP are references to Adamas Intelligence Inc. and not to any individual employed at Adamas.

SRK Consulting (U.S.) Inc. prepared all sections of the report that are not identified in this Section 2.8 as being prepared by SGS and Adamas. In sections of this report prepared by SRK, references to the Qualified Person or QP are references to SRK Consulting (U.S.), Inc. and not to any individual employed at SRK.

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3 Property Description and Location

MP Materials’ surface ownership includes approximately 2,222 acres (900 hectares (ha)). The County of San Bernardino General Plan previously designated the Official Land Use District for the majority of the site as Resource Conservation. In 2021, a rezoning was completed with the majority of the site designated for Regional Industrial (IR). The site is located within Improvement Overlay District 5, which applies to very rural areas with little or no development potential. The County Development Code permits mining in any land use district within the County subject to a conditional use permit.

The lands surrounding the Mountain Pass Mine site are mostly public lands managed by the Bureau of Land Management (BLM). The Mojave National Preserve, managed by the National Park Service, lies two to three miles to the north, west, and south of the site. The Clark Mountain Wilderness Area is located four miles northwest of the project site.

Current mining and mineral recovery operations include the following major activities and facilities at the mine site (Figure 3-1):

• A single open pit mine for extraction of the rare earth mineralization

• West and north overburden stockpiles (overburden consists of un-mineralized rock extracted from the pit)

• Crusher and mill/flotation plant

• Paste tailings disposal facility

• Mineral recovery plants (concentrator and separations facility)

• Offices, warehouses, and support buildings

• Onsite evaporation pond facility

• Product storage

• Stormwater ponds

The primary mineral of economic interest mined historically at the Project is bastnaesite, a light brown carbonate mineral that is significantly enriched with 14 of the lanthanide elements plus yttrium.

As the Mountain Pass operation is currently configured, the material is crushed and blended at the crushing plant and then transported to the concentrator. At the concentrator, the crushed ore is combined with recycled water and ground further in a ball mill. The slurry is then pumped to the downstream conditioning and flotation equipment to separate the rare-earth bearing minerals away from the gangue minerals. The primary product of the flotation process is a bastnaesite concentrate that prior to the commissioning of the rare earth separations facility discussed below, has been MP Materials’ primary product. This has been press filtered and packaged for export. Engineered containment facilities are used for storage and packaging of product.

MP Materials has recently recommissioned a REE separations facility at Mountain Pass that allows MP Materials to produce four saleable REE products: praseodymium and neodymium (PrNd) oxide, samarium, europium, and gadolinium (SEG+) oxide, lanthanum (La) carbonate, and cerium (Ce) chloride. As the REE separations facility ramps up, it is expected that all or nearly all of bastnaesite concentrate will be processed on-site to produce the saleable REE products.

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Source: MP Materials, 2023

Figure 3-1: General Facility Arrangement (WGS84 Coordinate System)

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3.1 Property Location

Mountain Pass is located in San Bernardino County, California, north of and adjacent to Interstate-15 (I-15), approximately 15 miles southwest of the California-Nevada state line and 30 miles northeast of Baker, California, at geographic coordinates 35°28’56”N latitude and 115°31’54”W longitude (Figure 3-2). This area is part of the historic Clark Mining District established in 1865. The Project lies within portions of Sections 11, 12, 13, and 14 of Township 16 North, Range 14 East, San Bernardino Base and Meridian.

Source: Google, 2023

Figure 3-2: Location Map

3.2 Mineral Title

Figure 3-3 illustrates the boundaries of the current mineral claims and surface rights associated with the Project, as provided by MP Materials. Mining claims and surface rights associated with the Project include:

• Patented claims with surface rights owned by MP Mine Operations LLC (MPMO) and mineral rights held by Secure Natural Resources LLC (“SNR”)

• Unpatented lode and mineral claims held by SNR

• Surface ownership by MPMO and mineral rights controlled by the State of California

• Surface ownership by MPMO and mineral rights controlled by the U.S.

• Surface ownership by School District and mineral rights controlled by the U.S.

The rare earth mineralization at the Project is located within land owned by MP Materials.

Historically, the surface and subsurface rights associated with the Project were held by Molycorp, Inc. (Molycorp), which filed for Chapter 11 bankruptcy protection in 2015. As part of the corporate restructuring in the bankruptcy proceedings, the former assets of Molycorp, associated with the

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Project, were split between multiple parties. This included MPMO, which purchased the real property (e.g., equipment, surface rights, water rights, surface use rights, access rights, easements, etc.) and SNR, which purchased the subsurface mineral rights and certain intellectual property. MPMO entered into a lease agreement with SNR on April 3, 2017, allowing MP Materials to extract rare earth products and byproducts from the Project mineral rights (note that this agreement excludes rights to all other minerals and hydrocarbons that could be present at the Project) and utilize the intellectual property, held by SNR. At the time of entering into the lease agreement, MPMO and SNR had shareholders common to both entities; however, they were not partners in business nor did they hold any other joint interest. On November 17, 2020, MPMO and SNR were combined with Fortress Value Acquisition Corp. (FVAC) and became wholly-owned subsidiaries of FVAC, which was in turn renamed MP Materials Corp. Consequently, the intercompany transactions between MPMO and SNR are eliminated in the consolidated financials of MP Materials Corp.

Discussion of each category of land ownership is provided in the following sections. Figure 3-3 provides a land tenure map. Listings of claims for MPMO and SNR as reflected on the Bureau of Land Management (BLM) website are located in Appendix A to this Technical Report Summary.

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Source: MP Materials, 2023

Figure 3-3: Land Tenure Map

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3.2.1 Nature and Extent of Registrant’s Interest

Surface Ownership by MP Materials and Mineral Rights by the State of California

The California State Lands Commission (CSLC) retains a mineral right in T16N, R14E, Section 13 (Figure 4-2). In a June 19, 2003, letter from the CSLC letter to the previous Project owner, “...the CSLC has advised San Bernardino County that the State acquired and patented certain lands within the proposed project boundary, reserving a 100% mineral interest in approximately 400 acres in the S1/2, SE1/4 of NE1/4, and the SW1/4 of the NW1/4 of Section 13, T16N, R13E, SBM. This interest is under the jurisdiction of the CSLC.” (CSLC, 2003).

Surface Ownership by MP Materials and Mineral Rights by the U.S. Government

The U.S. government holds the mineral rights to an approximate 2.25 square mile parcel of land located east of the planned area of operations.

Surface Ownership by School District and Mineral Rights by the State of California

The School District owns a 40-acre parcel of land adjacent to the Bailey Road highway exit. The State of California retains the mineral rights to this parcel. This mineral right is located to the south of the existing deposit and does not encroach on the ultimate boundaries of the open pit or overburden stockpiles. MPMO has entered into a lease with the School District for this parcel excluding those areas covered by the legacy school assets.

3.3 Royalties, Agreements, and Encumbrances

Several public service and utility easements and rights-of-way are located within the mine boundaries, including a Southern California Edison (SCE) electric utility easement and an AT&T right-of-way.

3.4 Environmental Liabilities and Permitting

MP Materials maintains financial assurance cost estimates for closure, PCM, and AKRFR for current and planned operations at the Mountain Pass property. The LRWQCB administers groundwater and surface water related financial assurance obligations. San Bernardino County administers financial assurance requirements for surface reclamation of the property. The California Department of Health, Radiological Health Branch administers financial assurance requirements for decontamination and decommissioning activities. MP Materials maintains miscellaneous financial assurance instruments for other closure-related obligations. Table 3-1 presents the current financial assurance obligations for the Mountain Pass property. The total financial assurance obligation is approximately US$45.4 million.

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Table 3-1: Current Financial Assurance Obligations

Regulatory Authority	Regulatory Obligation	FA Instrument	FA Instrument (US$)
Lahontan Regional Water Quality Control Board	Closure	Bond EACX4029377		14,777,095
	Post-Closure	Bond EACX4029378		4,697,948
	AKRFR	Bond EACX4029379		9,757,091
County of San Bernardino	Closure – Physical Grading, Capping, Vegetating and Monitoring	Bond EACX4029382		10,233,989
	Closure and Regrading of NW Evaporation Ponds	Bond EACX4029382		723,100
California Department of Resource, Recycling and Recovery	Closure – Landfill Post-Closure Monitoring	Bond EACX4029381 Bond EACX4029375		364,553 137,162
California Department of Public Health – Radiological Health Branch	Closure – Decommissioning of Industrial Facilities	Bond EACX4029380		4,442,667
Bureau of Land Management	Shadow Valley Fresh Water Wells ROW Wheaton Wash Wells	Bond EACX4029374 Bond EACX4029376		191,200 64,077
State Lands Commission	Fresh Water Pipeline ROW			20,000
Total			$	45,408,882

Source: MP Materials, 2023

Existing closure obligations include:

• Reclamation and closure of the existing overburden stockpiles and dry stack tailings facility

• Completing active Corrective Action Programs (CAP) for groundwater remediation

• Operation and ultimate closure of the on-site evaporation ponds

• Indirect costs associated with direct costs listed above

Existing post-closure obligations include annual inspection and maintenance for the following closed facilities:

• Pond P-1

• Pond P-16

• Community landfill

3.4.1 Remediation Liabilities

The AKRFR costs include approximately 20 years of ongoing groundwater extraction and treatment of a plume of impacted groundwater generated during historic operations. Pursuant to a 1998 clean up and abatement order issued by the LRWQCB, previous ownership conducted, and MP Materials continues to conduct various investigatory, monitoring, and groundwater abatement activities related to contamination at and around the Mountain Pass facility. These activities include soil remediation and the operation of groundwater monitoring and recovery wells, water treatment systems, and evaporation ponds.

3.4.2 Required Permits and Status

MP Materials holds conditional use and minor use permits from SBC, which currently allow continued operations of the Mountain Pass facility through 2042. MP Materials also holds permits to operate from the LRWQCB and the Mojave Desert Air Quality Management District. The Company has restarted

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the rare earth separations facility with some modifications to the process. The Company maintains the current permit authorization to operate the NWTDF and to co-dispose of other waste streams in the NWTDF. MP Materials anticipates these waste streams will meet the approved waste characterization profiles.

The updated mine plan extends open pit mining through 2048 and stockpile processing through 2056. MP Materials will be required to amend the conditional use permit from SBC to accommodate the updated mine plan. Section 17.2 provides further information.

3.5 Other Significant Factors and Risks

Full extraction of this reserve is dependent upon modification of current permitted boundaries. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit only includes waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume MP Materials will be able to negotiate a similar agreement.

SRK is not aware of any other risk items that can reasonably be assumed to impact access, title, right, or ability to perform work on the property.

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4 Accessibility, Climate, Local Resources, Infrastructure, and Physiography

The Project is located in San Bernardino County, California, north of and adjacent to Interstate 15 (I-15), approximately 15 miles southwest of the California-Nevada state line and 30 miles northeast of Baker, California (Figure 3-2).

4.1 Topography, Elevation, and Vegetation

The area is in the southwestern part of the Great Basin section of the Basin and Range physiographic province, which is characterized by a series of generally north to south-trending mountain ranges separated by broad, low-relief alluvial basins, which often have internal drainage (Peterson, 1981).

The Project occupies the highest elevation along I-15 between Barstow, California, and Las Vegas, Nevada. Elevations range from 4,500 to 5,125 ft above mean sea level (amsl), with most of the site located between 4,600 to 4,900 ft amsl. Clark Mountain (located northwest of the Project) is the highest local peak at 7,903 ft amsl.

The major habitat in the Project area is Mojave Desert scrub. Local surface drainages support a mixture of scrub and riparian species. Vegetation is characterized by various yuccas with a predominance of Eastern Joshua trees, larger shrubs, thorn bushes, and a host of smaller shrubs. Areas of ongoing disturbance in the Project area are barren of vegetation.

4.2 Accessibility and Transportation to the Property

The nearest major city is Las Vegas, Nevada, located 50 miles to the northeast on I-15. The Project lies immediately north of I-15 at Mountain Pass and is accessed by the Bailey Road Exit (Exit 281 of I-15), which leads directly to the main gate. The mine is approximately 15 miles southwest of the California-Nevada state line in an otherwise undeveloped area, enclosed by surrounding natural topographic features. I-15 follows the natural drainages, east-west between the Clark Mountain and Mescal mountains ranges, cresting at Mountain Pass Summit at an elevation of 4,730 ft amsl.

All access to the Project is controlled by MP Materials, and there is no public access through the Project area. All public access roads that lead to the Project are gated at the property boundary.

MP Materials maintains the existing infrastructure for the Project in support of mining and processing activities. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

4.3 Climate and Length of Operating Season

The climate at Mountain Pass is described as arid desert, generally hot and dry in the summer and mild in the winter, with limited precipitation and cloud cover. Based on Western Regional Climate Center Statistics, the coldest month of the year is January with an average minimum temperature of 29.5°F (-1.4°C). The warmest month is July with an average high temperature of 92.8°F (33.8°C).

Precipitation in the area of the mine averages 8.4 inches per year. The maximum precipitation from a single storm in the past 45 years was 5.9 inches (Geomega, 2000). Most storms yield a precipitation of 0.5 inch or less. Precipitation most frequently occurs during November through February, accounting for over 40% of the annual total rainfall. However, the most significant portion of the annual rainfall can

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occur as summer thunderstorms during July and August with average monthly precipitation above 1.0 inch per month during these two months. These storms may result in heavy rainfall and flash floods. The snowfall in the winter months can accumulate rapidly but has minimal effect on operations. Operations at the Project are year-round.

4.4 Infrastructure Availability and Sources

MP Materials has fully developed operating infrastructure for the Project in support of mining and processing activities. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

Given the relative proximity of the Project to the city of Las Vegas, Nevada, most personnel at the Project commute from the greater Las Vegas area. This regional city provides an adequate source of skilled and unskilled labor for the operation.

Outside services include industrial maintenance contractors, equipment suppliers, and general service contractors. Access to qualified contractors and suppliers is excellent due to the proximity of population centers, such as Las Vegas, Elko, Nevada (an established large mining district), and Phoenix, Arizona (servicing the copper mining industry).

Substantially all of the power to the Mountain Pass facility is currently supplied by a Combined Heat and Power (CHP) or co-generation (cogen) power facility with two natural gas-fired turbines capable of producing up to 26 MW of power combined. In addition, the site is served by a 12-kV line from a Southern California Edison substation two miles away.

Water is supplied through active water wells located eight miles west of the Project. Fire systems are supplied by separate fire water tanks and pumps.

Site logistics are straightforward with the concentrate product shipped in supersacks within a shipping container by truck approximately 4.5 hours to the port of Los Angeles. At the port, the containers are loaded onto a container ship and shipped to the final customers. Refined products for domestic customers are shipped in supersacks and intermediate bulk containers (IBC tote).

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5 History

5.1 Prior Ownership and Ownership Changes

The Molybdenum Corporation of America (MCA) purchased the Birthday claims and the Sulfide Queen properties in 1950 and 1951, respectively. In 1974, MCA changed its name to Molycorp, Inc. (“Old Molycorp”). In 1977, Union Oil of California (Unocal) purchased Old Molycorp and operated the company as a wholly-owned subsidiary. In 2005, Chevron Corporation purchased Unocal. On September 30, 2008, Chevron sold the Mountain Pass facility and Rare Earth business, including the rights to the name Molycorp, to a private investor group who formed Molycorp, LLC. Molycorp, Inc. (“Molycorp”) was formed on March 4, 2010, for the purpose of continuing the business of Molycorp, LLC in corporate form. Molycorp filed for Chapter 11 bankruptcy protection in June 2015. As part of the corporate restructuring in the bankruptcy proceedings, the former assets of Molycorp associated with the Project were split between multiple parties. This included MPMO, which purchased the real property (e.g., equipment, surface rights, water rights, surface use rights, access rights, easements, etc.) and SNR, which purchased the subsurface mineral rights and certain intellectual property.

MPMO entered into a lease agreement with SNR on April 3, 2017, allowing MP Materials to extract rare earth products and byproducts from the Project mineral rights (note that this agreement excludes rights to all other minerals and hydrocarbons that could be present at the Project) and utilize the intellectual property, held by SNR. At the time of entering into the lease agreement, MPMO and SNR had shareholders common to both entities; however, they were not partners in business nor did they hold any other joint interest. On November 17, 2020, MPMO and SNR were combined with FVAC and became wholly-owned subsidiaries of FVAC, which was in turn renamed MP Materials Corp. Consequently, the intercompany transactions between MPMO and SNR did not continue after the business combination.

5.2 Exploration and Development Results of Previous Owners

The mining history of the area began with the organization of the Clark Mining District in 1865. This district produced about US$5,000,000 in silver between 1865 and about 1895 (Olson et al., 1954). Between 1900 and 1920, many small lead, zinc, copper, gold, and tungsten mines were operated in the area.

Mining at Mountain Pass began in 1924 when prospectors identified galena (lead sulfide) on Sulfide Queen Hill, which is near the location of the existing open pit. Several small shafts and trenches were excavated by various operators; however, no ore was shipped. The Sulfide Queen mine was developed and worked for gold between 1939 and 1942, producing about 350 ounces of gold from an inclined shaft about 320 ft deep and about 2,200 ft of workings developed on four levels.

The discovery of rare earth mineralization at Mountain Pass was made in April of 1949 by prospectors searching for uranium. Having noted that samples from the Sulfide Queen gold mine were radioactive, prospectors returned to the area and discovered a radioactive vein containing a large proportion of a light brown mineral (bastnaesite) that the prospectors were unable to identify. This original discovery is known as the Birthday vein. The prospectors sent a sample of the unknown mineral to the United States Bureau of Mines (USBM) for identification.

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The USBM confirmed the bastnaesite discovery and made a public announcement in November 1949 (Olson et al., 1953). This attracted the attention of several mining companies, including MCA, which purchased the Birthday group of claims in February 1950. MCA sank a 100 ft-deep shaft on the Birthday claims, but no mineable ore was delineated, and development was stopped.

During this time, prospectors identified carbonatite dikes throughout a wider, adjacent area. The USGS proceeded to conduct detailed mapping of the entire Mountain Pass area. During this work, the USGS staff identified a massive body of carbonatite to the south of the Birthday claims, largely made up of barite, calcite, dolomite, and bastnaesite. Much of this carbonatite body was located on the original Sulfide Queen claims. MCA bought the Sulfide Queen claim group and the surrounding properties in January 1951. The existing gold mine and its associated equipment and buildings were also purchased, and a new crushing plant was installed. MCA drilled several hundred shallow churn holes in the following months and analyzed the cuttings for their rare-earth element contents (Olson et al., 1954).

Production of rare earth concentrate at the Project began in 1952, using the old gold plant, a new ball mill, and flotation cells from MCA’s Urad, Colorado, molybdenum property. Mining started on a portion of the deposit where the ore averaged more than 15% TREO. The production rate varied from 80 to 120 st per day.

MCA signed a contract with the U.S. General Services Administration to produce rare earth concentrates for the government stockpile. By 1954, MCA shipped one hundred and twenty 60 t carloads of bastnaesite concentrate to the government stockpile, thereby fulfilling the terms of the contract. Other markets for TREOs had not yet developed, and the mine and mill operated part-time with a small crew.

Due to the increasing demand for europium for use in color televisions, MCA constructed a europium oxide plant in 1965 and increased production six-fold from the previous year to approximately 6.1 million pounds (Mlb) of TREO concentrate. The following year, a new concentrator was completed with a capacity of 600 metric tonnes per day. At the start of 1965, MCA produced 6,000 pounds per year (lb/yr) of europium oxide. By year-end, production of europium oxide reached 20,000 lb/yr. By the end of 1966, total production at the Project had quadrupled to 24 Mlb/yr of TREO concentrates.

Old Molycorp (formerly MCA) undertook a major geologic evaluation program at Mountain Pass between 1976 and 1980. MCA and Old Molycorp drilled dozens of diamond drillholes between 1953 and 1992 for exploration, mine development, and condemnation. More than 300 new mining claims were added over ground which could potentially contain rare earth mineralization. Regional aeromagnetic and radiometric surveys were conducted within and beyond the known rare earth mineralization, and Landsat imagery for the region was evaluated. The geological program included characterization of the alkaline rocks and rare earth mineralization of the district and involved detailed geologic mapping and petrographic studies of the Sulfide Queen deposit and the surrounding rocks. Ground-based geophysical surveys were completed over the known bastnaesite-bearing carbonatite and associated intrusive rocks.

Due to the continued expansion of the rare earths market, a new separation plant was completed in 1982, which could produce samarium and gadolinium oxides up to 99.999% in purity by solvent extraction (SX). Subsequently, the plant was modified to produce high-purity terbium oxide for fluorescent lighting.

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In 1989, Old Molycorp began production of dysprosium oxide and increased its output of neodymium to satisfy the demand created by the growing neodymium-iron-boron permanent magnet industry. By 1990, lanthanide processing facilities at Mountain Pass expanded to produce various TREO concentrates. Between 1995 and 1997, Molycorp produced and sold in excess of 40 Mlb of rare earth oxide products per year. Limited mining of overburden and mineralized rock took place through 2002. The historical mill entered care and maintenance in 2002. Between 2007 and 2012, there was limited production of rare earth oxides from various types of stockpiled rare earth concentrates (primarily lanthanum concentrates and bastnaesite concentrate) through the historical separation facility.

In December 2010, under the new Molycorp, mining operations were restarted, and in January 2011, a major redevelopment project was initiated targeting modernization of milling and separation facilities. These new mining and separation facilities were intended to be developed in two phases, with the first phase targeting 19,050 metric tonnes (42 Mlb) of rare earth production per year and the second phase targeting 40,000 metric tonnes (88 Mlb) of rare earth production per year. This modernization included construction of a new mill, cracking facilities, separation facilities, and associated infrastructure, including power generation and reagent recycling facilities. The new separation facilities included production of cerium, lanthanum, neodymium, and praseodymium, with the remaining rare earths sold as a samarium, europium, and gadolinium (SEG) concentrate. During initial construction activities, Molycorp changed its development strategy and decided to build out capacity for both phases at the same time. Construction activities were largely completed by the end of 2013, with all first phase equipment constructed and most of the second phase constructed. Ramp up of the concentrator, separation facility and associated infrastructure (e.g., chlor-alkali/reagent recycling) encountered several issues that limited production and prevented operations from achieving targeted goals. 2013 production from Mountain Pass was approximately 7.7 Mlb of rare earth oxides, and 2014 production was approximately 10.5 Mlb. January through June 2015 production was approximately 8.1 Mlb of rare earth oxides. Molycorp declared bankruptcy in June 2015, and mining and processing operations were halted at that time.

The current owner, MP Materials, restarted milling and flotation operations in December 2017. MP Materials began production of separated REEs in 2023.

5.3 Historical Production

The reported historic production for the Mountain Pass deposit for the period 1953 through 1970, including the tonnage of mineralized and overburden materials mined, the plant feed grades and recovery, and pounds of rare-earth oxides produced, is shown in Table 5-1. The historic production from 1968 to 2002, including short tons mined, crushed, and milled, is presented in Table 5-2. Historic rare earth oxide production from 2009 to 2015, which includes reprocessing of existing stockpiles (2009 to 2012) and processing of freshly mined ore (2012 to 2015), is presented in Table 5-3. MP Materials’ historic rare earth oxide production from 2018 through September 2023 is presented in Table 5-4.

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Table 5-1: Production History, 1952 to 1970

Item	1952 to 1964		1965		1966		1967		1968		1969		1970(1)		Total
Waste stripped, st		0		0		0		15,000		20,000		85,000		14,000		134,000
Ore mined and fed to plant, st		255,375		37,476		179,721		201,233		193,100		259,097		182,290		1,308,292
Flotation Plant Feed, % TREO		9.1		10.2		9.1		8.3		8.1		7.5		7.2		8.3
Concentrate No. 400, klb TREO		31,934		6,094		12,873		16,483		2,361		2,188		7,519		154,444
Concentrate No. 401, klb TREO		0		0		11,139		8,001		20,408		25,155		10,289		0
Flotation Plant Recovery, %		68.6		80.1		73.0		73.2		72.7		70.5		68.1		0
Chemical Plant Feed, klb TREO		0		6,899		18,380		13,198		14,087		19,604		11,178		83,346
RE Oxide Nos. 410/411, klb TREO		0		275		282		307		1,731		409		0		3,004
Cerium Nos. 530/ 532, klb CeO2		0		0		1,925		1,668		1,680		1,901		1,672		8,846
Lanthanum, 521, klb TREO		0		0		0		3,250		6,669		7,568		5,522		23,009
Lanthanum, 523, klb TREO		0		0		306		501		249		28		64		1,148
Neo-Praseo No. 545, lb Pr6O11		0		0		0		0		0		74,702		3,677		78,379
Gadolinium No. 573, lb Gd2O3		0		0		0		0		17,084		17,881		13,990		48,955
Gad-Sam No. 575, lb TREO		0		0		0		9,961		12,095		0		0		22,056
Samarium No. 583, lb Sm2O3		0		0		0		0		29,600		0		0		29,600
Europium Nos. 500/ 501/ 510/510B/ 511, lb		0		1,845		11,384		9,058		3,234		7,847		8,226		41,594

Source: Mountain Pass monthly operational reports

⁽¹⁾: Through October 31, 2007

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Table 5-2: Mine Production History, 1971 to 2002

Year		Mined (st)		Crushed (st)		Milled (st)		Overburden (st)
	1971		214,000		181,175		181,175		No data
	1972		163,000		228,488		228,488		No data
	1973		303,000		305,072		305,073		No data
	1974		479,000		499,597		499,596		9,100
	1975		296,693		296,693		296,693		70,100
	1976		355,253		308,938		308,938		73,980
	1977		314,946		321,508		321,508		66,255
	1978		292,760		266,757		266,757		132,200
	1979		326,010		358,399		358,399		327,760
	1980		386,927		360,068		360,068		219,345
	1981		371,553		370,207		370,207		225,691
	1982		400,428		400,427		391,417		221,625
	1983		485,315		322,771		371,252		226,000
	1984		621,714		439,000		543,354		728,000
	1985		365,000		204,000		253,000		1,233,000
	1986		343,000		214,000		225,000		1,225,000
	1987		402,000		320,000		358,000		1,072,000
	1988		143,000		214,000		221,764		1,049,000
	1989		445,000		419,000		418,446		1,610,000
	1990		706,000		508,000		480,161		1,749,000
	1991		404,000		446,000		336,344		2,477,000
	1992		275,000		247,000		409,000		1,771,000
	1993		540,000		447,000		433,000		1,232,000
	1994		567,000		494,000		508,000		1,217,000
	1995		714,000		546,000		537,000		2,388,000
	1996		604,000		551,000		544,000		2,312,000
	1997		632,000		452,000		424,000		3,355,000
	1998		234,000		269,000		321,000		688,000
	1999		94,000		0		0		43,000
	2000		78,000		0		0		239,000
	2001		175,010		260,000		175,010		634,000
	2002		201,520		217,204		183,487		255,520

Source: Mountain Pass monthly operational reports

Mill quantities do not include tailings that were reprocessed.

Between 1975 and 1982, crushing tonnages were not recorded (assumed to be the same as milling tonnages).

Table 5-3: Mountain Pass Production History, 2009 to 2015, as Separated RE Products

Year		TREO Production (Metric Tonnes)
	2009		2,103
	2010		1,296
	2011		3,062
	2012		2,236
	2013		3,473
	2014		4,769
	2015(1)		3,678

Source: Molycorp 10-K and 10-Q filings

⁽¹⁾: January to June production

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Table 5-4: Mountain Pass Production History, 2018 to 2023, as Bastnaesite Concentrate

Year		TREO Production (Metric Tonnes)
	2018		13,913
	2019		28,442
	2020		38,561
	2021		44,413
	2022		42,500
	2023(1)		32,299

Source: MP Materials

⁽¹⁾: January to September production

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6 Geological Setting, Mineralization and Deposit

6.1 Regional Geology

Mountain Pass is located in the southern part of the Clark Range in the northern Mojave Desert. The Mojave is situated in the southwestern part of the Basin and Range physiographic province which extends from central Utah to eastern California and is characterized by Tertiary extensional deformation and associated volcanics. This deformational event resulted in north-south trending mountain ranges separated by elongated valleys, characteristic of Basin and Range topography. The Mountain Pass rare earth deposit is located within an uplifted block of Proterozoic metamorphic and igneous rocks that is bounded to the south and east by basin-fill deposits in the Ivanpah Valley. This block is separated from Paleozoic and Mesozoic rocks on the west and southwest by the Clark Mountain thrust complex, which strikes north-northwest and dips from 35° to 70º west but averages 55 Wº. The North Fault forms the northern boundary of the block, striking west-northwest and dips from 65° to 70° south (Olson, et al., 1954; Castor, 2008). Geology of the Mountain Pass property is shown in Figure 6-1.

There are two main groups of rocks in the Mountain Pass area divided by age and rock type. These are Early Proterozoic high-grade metamorphic rocks, which are intruded by unmetamorphosed Middle Proterozoic ultrapotassic and carbonatite rocks. The Early Proterozoic high-grade metamorphic complex represents a wide variety of compositions and textures, as follows:

• Garnetiferous micaceous gneiss and schist

• Biotite-garnet-sillimanite gneiss

• Hornblende gneiss, schist, and amphibolite

• Biotite gneiss and schist

• Granitic gneiss and migmatite with associated granitic pegmatite

• Minor occurrences of foliated mafic rocks

The Middle Proterozoic ultrapotassic rocks are intrusive bodies of granite, syenite, and composite shonkinite-syenite, which contain augite and orthoclase. These have been intruded by carbonatites which formed swarms of thin dikes, stocks, and the tabular Sulfide Queen carbonatite currently the focus of mining activities (Olson et al, 1954; Castor 2008). The Middle Proterozoic ultrapotassic rocks have been age dated using U-Th-Pb and ⁴⁰Ar-^-39Ar methods at 1,410 ± 5 Ma and 1,403 ± 5 Ma for shonkinite and syenite respectively. The rare earth-bearing carbonatite units, including the Sulfide Queen deposit, are younger with age dates, using Th-Pb ratios, of 1,375 ± 5 Ma (DeWitt et al, 1987). Both the Early Proterozoic metamorphic rocks and the Middle Proterozoic intrusive rocks have been crosscut by volumetrically minor, Mesozoic to Tertiary age dikes of andesitic to rhyolitic composition. Large portions of the Mountain Pass district are covered by younger (Tertiary to Quaternary) basin-fill sedimentary deposits (Olson et al, 1954; Castor 2008) (Figure 6-1).

Significant rare earth mineralization is only associated with carbonatite intrusions. Strongly potassic igneous rocks of approximately the same age are known from other localities in and around the Mojave Desert, but no significant carbonatite bodies or rare earth mineralization have been identified (Haxel, 2004).

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Source: Geomega, 2012

Figure 6-1: Regional Geological Map

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6.2 Local and Property Geology

At Mountain Pass, the ultrapotassic rocks occur in seven larger stocks and as hundreds of smaller dikes. The largest single body is a composite shonkinite-syenite-granite stock approximately 6,400 ft in length and 2,100 ft wide (Olson, et al., 1954). These rocks span a variety of compositions, from phlogopite shonkinite (melanosyenite) to amphibole-biotite (mesosyenite and leucosyenite) to alkali-rich granite (Haxel, 2005). These complex and varied lithologies are believed to be sourced from the same parent magma formed from partial melting of the upper mantle (asthenosphere) beneath the North American continent during the Middle Proterozoic. The different compositions reflect different phases of magma differentiation (Castor, 2008). A generalized geologic map of the area is shown in Figure 6-2.

The Sulfide Queen carbonatite, which hosts the mineralization at the Project is referred to as a stock but is a roughly tabular, sill-like body that strikes approximately north and dips to the west at about 40° as shown in Figure 6-3. The carbonatite-bearing magma is believed to have formed by liquid immiscibility, separating from the same parent magma which formed the ultrapotassic rocks occurring nearby (Castor, 2008).

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Source: Castor, 2008

Figure 6-2: Generalized Geologic Map – Sulfide Queen Carbonatite

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Source: Castor, 2008

Note: Section looking N-NE

Figure 6-3: Schematic Cross Section (A-A’) of Sulfide Queen Carbonatite

6.2.1 Local Lithology

In the open pit and to the south, east and west, lithology is dominated by gneiss and the Sulfide Queen carbonatite. Immediately north of the pit, carbonatite is found at surface and a small outcrop of syenite is found adjacent to and on the east flank of the Sulfide Queen. The Sulfide Queen extends to the contact with shonkinite and ultrapotassic granite approximately 650 ft northwest of the open pit boundary.

The carbonatite rocks at the Project have been divided by geologists at Mountain Pass into six types:

• Bastnaesite sövite (Bastnaesite-barite sövite)

• Bastnaesite beforsite (Bastnaesite-barite sövite)

• Bastnaesite dolosövite (Bastnaesite-barite dolomitic sövite)

• White sövite (White bastnaesite-barite sövite)

• Parisite sövite (Parisite sövite)

• Monazitic sövite (Monazite-bearing carbonatite)

These divisions are based on the carbonate mineral composition of the carbonatite, either calcite or dolomite, the dominant rare earth mineral, texture, and other criteria detailed in the following sections

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(based largely on Castor, 2008). The different carbonatite types and their specific mineralization are discussed in detail in Section 6.3.

Breccia is found within and adjacent to the Sulfide Queen and includes altered clasts of country rock as well as carbonatite. It is most abundant in the northern part of the open pit and to the south under the former mill. Breccia textures range from matrix to clast supported breccia with rounded to angular clasts. In the hangingwall of the Sulfide Queen, breccia occurs as a stockwork while in other areas it appears to have formed by intrusive stoping. In the footwall of the carbonatite, the breccia is composed of rounded and crushed gneiss, syenite and shonkinite, which is interpreted by Castor (1988, 2008) as indicating a pre-carbonate intrusive formation. Breccia has previously been thought to be unmineralized but contains monazite in places.

A simplified stratigraphic column is presented in Figure 6-4 showing the primary lithology types on the property.

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Source: SRK, 2023

Figure 6-4: Simplified Stratigraphic Column for the Mountain Pass Site

6.2.2 Alteration

Alteration at the Property is primarily contact metamorphism associated with the emplacement of the Sulfide Queen carbonatite. It is primarily fenitic alteration and found in the country rock adjacent to the

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carbonatite. Fenitic alteration or fenitization is associated with carbonate-rich fluids and is characterized by secondary potassium feldspar, phlogopite, and magnesio-riebeckite with chlorite and hematite in places. Due to the resulting distinctive color and textures of these minerals, the fenitic alteration type is relatively easy to recognize in outcrop and drill core by its light-colored minerals. Fenitization is typically less intense and widespread proximal to the ultrapotassic rocks relative to the intense alteration observed in the more reactive Middle Proterozoic rocks in the open pit area (Castor, 1988, 2008).

Other alteration identified locally includes hydrothermal alteration and silicification around the Celebration Fault. This is considered late stage and has little effect on mineralization (Castor, 1988; 2008). Additionally, weathering from meteoric water resulting in oxidation and hydration of minerals is commonly observed in the pit resulting in depleted carbonate minerals and thus, enrichments in TREO.

The presence of sillimanite in the biotite-garnet-sillimanite gneiss indicates that rocks of the Middle Proterozoic age reached high temperatures and pressures during metamorphism and were metamorphosed to the granulite facies. The carbonatite sills are not metamorphosed, and the Late Proterozoic age ultrapotassic rocks show limited contact metamorphism where these rocks host carbonatite.

6.2.3 Structure

Structural controls include local brecciation and faulting. Regional structural controls include the Clark Mountain Thrust and North Faults, which bound the block separating the Proterozoic rocks at the Property from the surrounding Paleozoic and Mesozoic age rocks. The Clark Mountain Thrust fault strikes north-northwest and dips from 35° to 70º W but averages 55º W. The North Fault strikes west-northwest and dips from 65° to 70º S and has offset the Clark Mountain Thurst by an estimated 1,200 ft near the Property. In general, all major faults in the Property area strike north-westerly and dip to the southwest. This includes the Middle and South Faults near the open pit (Olsen et al., 1954; Castor, 2008).

Within the open pit area, the important faults are the Ore Body, Middle, and the Celebration faults. The Ore Body Fault is a splay of the North Fault and the carbonatite and ultrapotassic rocks are found primarily between the Middle and Ore Body Faults. Both are normal faults that strike northwest and dip moderately to steeply southwest. Both faults display evidence of left-lateral and dip-slip displacements and were active until the Pliocene-Pleistocene. Both faults contain substantial gouge zones and are barriers to groundwater flow. Many smaller faults with similar orientations and displacement have been mapped between these two faults.

The Celebration Fault transects the open pit along the highwall and dips into the pit. It also functions as a groundwater conduit and is a target for two dewatering wells. This structure is sub-parallel to the Middle Fault and strikes at an average of N60º W with a dip of approximately 60° SW. Although appreciable dip-slip offset is not noted north of 800 NW on the mine grid, shallowly plunging slickensides indicate a component of right lateral strike-slip motion. The Celebration Fault is marked by a 10 to 20 ft wide zone of shearing and brecciation with only local cementation. The Friendship Fault is visible in the pit, dips approximately 78º NE, and is considered to be a splay of the Celebration Fault. Information from drilling indicates that the Sulfide Queen carbonatite is offset downdip by a series of faults with limited displacement. These structures are sub-parallel to the Friendship Fault, do

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not offset the Celebration Fault, and displacement of the Sulfide Queen carbonatite is less than 100 ft in most places (Castor, 1988; Molycorp, 2003; Nason, 2009).

6.3 Significant Mineralized Zones

Mineralization occurs entirely within the Sulfide Queen carbonatite within the Project area. This has been defined through drilling and mapping. Grade distribution internal to this mineralized zone is variable. Higher grade zones (>10% TREO) tend to occur in lenses parallel to the hangingwall - footwall contacts, both downdip, and along strike. High grade also occurs along faults which have variable orientations due to meteoric water in faults dissolving carbonate minerals resulting in elevated concentration of bastnaesite in a weathered host rock. Continuity of mineralization internal to the carbonatite zone is well defined both along strike and downdip.

The currently defined zone of rare earth mineralization exhibits a strike length of approximately 2,750 ft in a north-northwest direction and extends for approximately 3,000 ft downdip from surface. The true thickness of the >2.0% TREO zone ranges between 15 to 250 ft.

The principal economic mineral at the Project is bastnaesite, a rare earth fluorocarbonate with the generalized chemical formula LnCO₃F, where Ln is a variable representing a lanthanide elemental component (usually lanthanum or cerium). This naming convention is applied throughout this resource report. The bastnaesite composition at the Project is dominated by cerium, lanthanum, and neodymium, with smaller concentrations of praseodymium, europium, samarium, gadolinium, dysprosium, terbium, and heavier rare-earth elements.

Bastnaesite mineralization at the Project were subdivided by Castor (1988, 2008) as described below. Non-mineralized rock types within the open pit area are also described.

6.3.1 Bastnaesite Sövite

Bastnaesite-sövite is a calcite-rich mineralized rock type containing relatively coarse, early-formed bastnaesite, along with recrystallized barite phenocrysts, in an anhedral matrix of fine calcite and barite. Where unaltered, this material is a pink to mottled white and red-brown rock carrying about 65% calcite, 25% strontian barite, and 10% bastnaesite. However, chemical and mineralogic changes subsequent to crystallization have produced more complex mineralogy. The sövite is characterized by relatively high calcium, strontium and lead, moderate barium, and low phosphorous.

The bastnaesite sövite forms the basal portions of the resource area, and all of the resource at the north end of the pit. At the south end of the pit, sövite makes up less than half the mineralized zone thickness.

Celestite occurs in the bastnaesite sövite as bladed replacements and outgrowths from barite phenocrysts. Celestite is particularly abundant, along with variable amounts of very coarse bastnaesite, in a basal sheet of otherwise unaltered sövite about 50 ft thick. This celestite sövite zone is separated from the main mineralized body by a zone of gneiss and/or breccia. Late celestite veins have been observed cutting talc-altered sövite.

Dark brown or ochre limonite is locally pervasive in sövite, particularly in silicified ore. Such rocks rarely have higher iron contents than unaltered sövite. Coarse bastnaesite typifies sovitic mineralized rock. On the 4640 level the average bastnaesite grain diameter is about 300 µm. For the most part, monazite

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[LNPO₄)] occurs sparingly in the sövite, almost always as small primary euhedral and patches of radial secondary needles.

6.3.2 Bastnaesite Beforsite

The bastnaesite beforsite unit generally lies above the sovitic material and is separated from it by dolosovite. Bastnaesite beforsite is a carbonate-rich mineralized rock type, containing ferroan dolomite (ankerite) as the major carbonate phase, instead of calcite, and is largely unaltered. Locally this rock contains minor quartz. Beforsite is tan or grey to pinkish tan and contains abundant grey or purple to pink and white single-crystal barite phenocrysts. The matrix consists mainly of fine dolomite rhombs set in very fine interstitial material consisting mainly of bastnaesite with calcite and barite. The mineralogical composition of an average beforsite is about 55% dolomite, 25% barite, 15% bastnaesite, and 5% calcite. Zones of barite-rich beforsite, associated with barite-poor zones have been logged in core holes and noted during pit mapping. Compared with the sövite, beforsite in pit samples has higher Ln and Ba, along with lower Sr and Pb. Phosphate content is variable but can be high in areas of irregular late veinlets of felty monazite. This is known as “bone” monazite and can be as much as 5% of the rock.

Dark brown limonitic alteration occurs in places in the beforsite, particularly along faults and in structural zones. In many instances, the limonite forms rhomb-shaped pseudomorphs indicating it formed by replacing the ferroan dolomite. In addition, secondary lanthanide minerals occur in portions of the beforsite such as sahamalite [(Mg,Fe²⁺)Ln₂(CO₃)₄], synchisite [synchysite, CaLn(CO₃)₂F] and ancylite [SrLn(CO₃)₂(OH)•H₂O] which was also identified using XRD. Large amounts of these secondary LN carbonates occurring within beforsite are associated with secondary calcite. Along the south wall of the pit, the beforsite contains crude, nearly vertical banding. On close examination, this is seen to consist of braided discontinuous veins of late bastnaesite/calcite. This texture probably formed by upward streaming of lanthanum and calcium-rich residual fluids remaining in the beforsite after dolomite crystallization.

6.3.3 Bastnaesite Dolosovite

Bastnaesite dolosovite occurs in a 100 to 200 ft wide zone between the beforsite and sövite. It contains both dolomite and calcite and is generally limonitic. Similar to the beforsite, dark brown limonite commonly forms pseudomorphs after dolomite rhombs. The dolosovite generally contains white to pink recrystallized barite phenocrysts. Some dolosovite samples contain coarse bastnaesite as in the sövite, but often samples have fine, late beforsite-style bastnaesite. A line drawn along the interface between the zone of coarse-grained (greater than 150 µm) bastnaesite average crystal sizes and the zone characterized by fine (less than 150 µm) average crystal size roughly bisects the bastnaesite dolosovite zone.

Chemically, the dolosovite shows both sovitic and beforsitic attributes. It is highly variable in terms of gangue mineralogy, particularly with regard to the carbonate minerals which show much evidence of secondary redistribution. In some samples, dolomitization is obvious, along with later limonitic replacement of the dolomite. In other locations, late white to brown calcite veining is abundant.

Some consider the dolosovite to be a hybrid rock and not a separate intrusive type. In this case, it is plausible it was formed by carbonate redistribution during and after intrusion of the beforsite. Based on bastnaesite grain size, it is mainly dolomitized sövite; but contains some finely divided bastnaesite

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and is in part calcitized beforsite. Strongly limonitized dolosovite, referred to as “black ore”, creates extreme milling problems. “Black ore” is mainly restricted to the dolosovite but in places extends into the beforsite. This material is generally dark brown soft material with white calcite veining. It typically exhibits high lanthanum content, carrying large amounts of coarse-  or fine-grained bastnaesite. In part, the elevated lanthanide (Ln) values may be due to removal of carbonate, resulting in an abundance of void space allowing the formation of larger grain sizes. This material generally has relatively low densities and is poorly indurated. Analysis of this rock type shows that bastnaesite dolosovite has above average iron, manganese, and phosphorous contents as compared with the bastnaesite sövite.

The bastnaesite dolosovite has high strontianite contents derived from sovitic rock. It is locally high in fine, anhedral, late-stage silica. Although the dolosovite appears to be dominated by alteration minerals, it rarely contains talc.

Ln-bearing minerals other than bastnaesite commonly occur in the dolosovite, though mainly as minor phases. Bright yellow synchisite replacing bastnaesite was observed in many thin sections. Secondary sahamalite and ancylite have also been identified in many dolosovite samples. Bastnaesite in dolosovite is generally yellow-brown or dark-brown, rather than in normal light tan to grey colors. Bone monazite is more abundant than primary monazite.

6.3.4 White Sövite

White sövite occurs above the beforsite in the southwest corner of the pit (current pit bottom 4,300 ft). It carries very fine, late bastnaesite as in the beforsite, but contains little or no dolomite. White sövite appears to be the product of late stage calcitization of beforsite by rising residual fluids responsible for late bastnaesite/calcite deposition in the underlying beforsite.

In addition to fine bastnaesite, the white sövite contains abundant single-crystal barite phenocrysts as in the beforsite. Chemically, white sövite has high Ln and low Pb relative to beforsite. Its Sr content ranges from low to moderate. Phosphate contents are variable, with most present as veins of bone monazite.

On the 4,640 level, the white sövite is exposed as a thick dike within hangingwall stockwork breccia 10 to 20 ft above the beforsite. Drillhole 85-1 intercepted 80 ft of white sövite before encountering dolomitic carbonatite.

6.3.5 Parisite Sövite

Parisite sövite is found in the pit above the 4,700 level in the footwall. A dike carrying about 20% of flow-oriented parisite [CaLn₂(CO₃)₃F₂] was mapped on the 4,760 level at the south end of the pit. This dike was intercepted in core hole 85-2.

6.3.6 Monazitic Carbonatite

Bodies of carbonatite which contain primary monazite in amounts that approach or exceed bastnaesite contents occur within, and adjacent to, the mineralized zone. In addition, monazitic sövite comprises most of the small carbonatite dikes in the vicinity of the mineralized zone.

The monazitic carbonatite has low total TREO content, generally in the 2% to 4% range. It is also characterized by high Ca and P, and low Ba. In hand specimen, the monazitic carbonatite is nearly equigranular because barite phenocrysts are sparse or lacking.

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Although sovitic and beforsitic carbonate rock types have both been documented, nearly all of the monazitic-bearing carbonatite rocks observed on the 4,700 to 4,640 levels are dolosovite. Monazite sövite is abundant in core holes drilled on the north part of the pit. Significant amounts of monazite dolosovite occur at the south end of the mineralized zone and extend beneath the mill.

Monazitic carbonatite is generally associated with brecciated rocks. Small, phlogopitized clasts are commonly present in the monazite carbonatite as well as phlogopite xenocrysts. At the north and south ends of the pit monazitic carbonatite appears to form envelopes around breccia masses. A large monazite dolosovite mass along the hangingwall of the deposit contains areas rich in clasts.

The monazite in the monazitic carbonatite occurs predominantly as primary euhedra or subhedra. Bone monazite replaces primary crystals in some samples. Where present, bastnaesite occurs as sparse corroded grains, generally observed in coarser sizes similar to those documented in the basal sövite.

The location of monazitic carbonatite masses, and the lack of barite phenocrysts suggest the monazitic magma was filter pressed out of the adjacent breccias. Formation of the monazitic carbonatite units probably post-dated sövite emplacement and predated beforsite emplacement.

Alteration in the monazitic carbonatite is similar to that observed in the dolosovite. However, “black ore” formed from monazitic carbonatite has not been recognized to date.

6.3.7 Breccia

Breccia with a carbonatite matrix comprises a significant proportion of the Mountain Pass carbonatite body. Like the related monazitic carbonatite, the breccia nearly always has low lanthanum oxide (LnO) and high P and has historically not been added to mill feed in significant quantities. Breccia has been observed in abundance at the north end of the current pit, and essentially limits mining in that direction due to metallurgical concerns. Breccia is also present at the south end of the pit, where considerable tonnages extend under the current mill location.

Breccia occurrences associated with the main carbonatite body at the Project are variable. The breccia bodies were previously noted to be semi-continuous envelopes on the hangingwall and footwall contact with the carbonatite intrusion and interlayered within the mineralized rock types. In the hangingwall, they range from stockworks of randomly oriented or sheeted carbonatite dikes cutting altered gneiss, clast-supported breccia with more than 70% altered angular clasts, to matrix-supported breccia with angular to rounded clasts which locally grades into monazitic carbonatite with sparse clasts.

In the footwall, abundant rounded clasts of gneiss, shonkinite, and syenite occur in a crushed rock matrix with little or no carbonatite. This breccia grades to matrix supported breccia with rounded clasts. Some footwall breccia has protomylonitic textures, along with occurrences of talc and crocidolite. Breccia at the north end of the pit is strongly altered to talc, which renders clast identification difficult. Brecciated zones have also been observed internal to the main carbonatite body.

6.4 Surrounding Rock Types

The carbonatite stock at the Project is intruded into the metamorphic rocks and the ultrapotassic suite. Both of these rock types are typically strongly fenitized near their contacts with carbonatite, and fenitized clasts are commonly included in igneous breccias at the edges of the intrusion (Castor, 1988).

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6.5 Relevant Geological Controls

The primary geologic control on mineralization is lithology; and only the carbonatitic rock types appear to be favorable for economically significant rare earth mineralization. Although a number of high-angle normal faults bisect the mineralized zone, offset appears to be post mineral in all cases.

6.6 Deposit Type, Character, and Distribution of Mineralization

Mountain Pass is a carbonatite hosted rare earth deposit (USGS Deposit Model 10; Singer, 1986). The mineralization is hosted principally in carbonatite igneous rock. Mountain Pass is the only known example of a rare earth deposit in which bastnaesite is mined as the primary magmatic economic mineral in the world (Haxel, 2004).

Mineralization occurs entirely within the carbonatitic portion of the currently drilled geologic sections, although grade distribution internal to this mineralized zone is variable. Higher grade zones (>10% TREO) tend to occur in lenses parallel to the hangingwall/footwall contacts, both downdip and along strike. Continuity of mineralization internal to the carbonatite zone is well defined both along strike and downdip.

The currently defined zone of rare earth mineralization exhibits a strike length of approximately 2,750 ft (850 m) in a north-northwest direction and extends for approximately 3,000 ft (930 m) downdip from surface. The true thickness of the >2.0% TREO zone ranges between 15 to 250 ft (5 to 75 m).

Globally, carbonatites are subdivided into two main groups: apatite-magnetite bearing, mined for iron and/or phosphorus ± various by-products, and rare-earth bearing carbonatites. Many other commodities may be present in economically significant concentrations, such as uranium, thorium, titanium, copper, vermiculite, zirconium, niobium, and phosphorus. The majority of carbonatite complexes display a series of variable carbonatitic magma compositions, the majority of which are not significantly enriched in rare earths. Mountain Pass is unique in that the carbonatite does not exhibit such variation and has significant intervals of elevated rare earths throughout its entirety.

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7 Exploration and Drilling

7.1 Exploration

In 1949, the rare earth-bearing carbonatite was discovered by a USGS field team (Olson, et al., 1954). The discovery and exploration details of Mountain Pass were published in USGS Professional Paper 261, which included regional and local scale geological and structural maps as well as maps of the underground workings at the Sulfide Queen Mine. USGS Professional Paper 261 details petrography, mineralogy, and chemical analyses in addition to structural and geologic data collected by the USGS. This document served as the basis for further exploration and eventual exploitation of the Mountain Pass Mine.

There is no other relevant exploration work on the property, other than drilling, conducted by or on behalf of current and previous owners at the Mountain Pass Mine. Drilling is discussed in Section 7.2. The USGS has conducted regional exploration work which is largely focused outside the Mountain Pass property.

7.2 Drilling

Extensive drilling at the Mountain Pass mine has been undertaken since the 1950’s, some of which is utilized to define the orebody and relevant geological features. The prior owner, Molycorp, completed drilling campaigns in 2009, 2010 and 2011. Data prior to those exploration campaigns are considered historical in nature. While this historical data provides geological and grade information, the historical drilling has no quality control (QC) data associated with it. In 2021, MP Materials performed a limited geotechnical and exploratory drilling campaign and handled core logging/sampling in a similar manner to the 2009-2011 drilling.

The 2009 drilling campaign consisted of an infill drilling program to upgrade the resource classification within and adjacent to the existing Sulfide Queen area. The program consisted of twelve, 5.5-inch reverse circulation (RC) holes around the south, west, and north sides of the pit. The 12 holes ranged in depth from 230 to 1,245 ft (70.1 to 379.5 m) and were drilled between December 2009 and February 2010. Sampling was done on 5 ft (1.524 m) intervals, and the bagged samples were delivered by SRK to the on-site sample prep facility. Among the 12 holes, MP-09-01 is missing all data.

The 2010 program was designed as a diamond drill hole (DDH) in-fill, exploration, and condemnation program. The program consisted of two DDH infill holes on the south side of the pit, two DDH exploration holes north of the pit, and two condemnation holes. One condemnation hole was complete as a DDH drilled northwest of the existing waste rock dump to test a possible future tailings site; the other was a RC hole drilled northeast of the pit, at the site of the separation plant expansion. Core sampling was conducted on 5 ft intervals and bagged samples were stored at the on-site sample preparation facility. RC samples were submitted as approximate 10-kilogram (kg) splits of the original recovered sample.

In 2011, Molycorp completed a DDH infill drilling campaign. In addition to routine total rare earth assaying, Molycorp randomly selected 683 core samples for laboratory analysis of the individual light rare earth components.

Core recoveries from the 2009 and 2010 drill campaigns exceeded 95%. MP Materials has noted similar results for the 2011 and 2021 drilling as well. Sample protocols described in Sections 8.1

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through 8.3 of this report provide reproducible results. SRK is of the opinion that drilling and sampling in these campaigns provides generally accurate and reliable results.

MP Materials conducted a geotechnical / exploration DDH drilling campaign in 2021 with 16 holes drilled at a total depth of 10,136 ft for geotechnical and resource evaluation purposes. All cores have been sampled at an interval of 10 ft on host rocks, and 5 ft on mineralized samples.

Figure 7-1 illustrates the locations of the drillholes, color coded by drill campaign. Several drillholes are located outside of the field of view but these do not impact the mineral resource model which is shown as block grades on the pit surface.

Source: SRK, 2019

Note: colored points are drill collars shaded by relative approximate date of drilling.

Figure 7-1: Drilling in MP Materials Pit Area

Geotechnical data for the project was acquired by detailed rock fabric mapping of surface exposures and subsurface sampling using drill core. SRK has reviewed the industry-accepted procedures and methods used by Call and Nicholas, Inc. (“CNI”), which are documented in Nicholas & Sims (2001) to characterize the rock mass. In SRK’s opinion, the geotechnical conditions are well characterized, and a sufficient number of holes have been drilled into the final pit wall to interpret the ground conditions.

CNI conducted laboratory testing to determine the intact and fracture strengths of the rock mass at their laboratory in Tucson, Arizona. Laboratory testing at this laboratory is done in general accordance with procedures outlined in ASTM standards for rock and soil testing. Using the intact and fracture strengths, rock mass strength estimates were developed using a procedure outlined in the Guidelines for Open Pit Slope Design (Read & Stacey, 2009). SRK has reviewed the rock mass strength calculations and inputs to the stability analysis. SRK concurs with the methods, approach, and results of the documented geotechnical study and interpretation of the results. Further discussion of the geotechnical parameters used for open pit mine design is presented in Section 13.1.

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8 Sample Preparation, Analysis and Security

The majority of data in the resource database is from historical drilling conducted prior to 2009. SRK has relied on prior discussions, from the time of Molycorp ownership, with former site geologists (e.g., Geoff Nason and John Landreth) for description of sample collection, preparation, analysis, and security (Nason and Landreth; personal communication; 2009). SRK conducted a verification program at the Project between 2009 and 2010 that included reanalysis of archived core from historic drilling programs and a limited infill program. This is discussed in Section 9.2.

No additional drilling was completed until 2021, during which MP Materials drilled a series of 16 holes for geotechnical purposes (GT series), some of which were in carbonatite zones and featured mineralization. Similar to previous programs, samples were processed and analyzed at the on-site laboratory with duplicate samples analyzed by an outside lab for validation. SRK is of the opinion that the sample preparation, security, and analytical procedures are adequate for reliance in the mineral resource estimation. Any uncertainty related to the historical or variable nature of the analyses are addressed in mineral resource classification as described in Section 11 of this report.

8.1 Sampling

8.1.1 Historical Sampling Procedures

The sample and drilling procedures prior to 2009 described by Nason and Landreth (2009) indicate that during drilling, the core or drill cuttings were in the custody of the drillers or geologists or secured in an onsite storage location at all times. Field geologists delivered samples to the sample preparation area. The sample preparation and laboratory facilities were within the secured Mountain Pass property boundary. This was industry standard practice at the time for ongoing exploration at an operating mine. Access to the Mountain Pass Mine is controlled by security at the gate 24 hours per day. Drilling since 2009 has been conducted in and around the open pit, which is a restricted area. All drill cores and RC samples were transported from the drill sites by a Molycorp employee and stored in a secure storage area until the core or RC chips were logged. Sample security was controlled and supervised by Molycorp personnel. Molycorp observed accepted industry practice chain of custody.

Nason and Landreth (2009) described the sampling methods prior to 2009. After the core was logged, a geologist selected sample intervals for analysis. Sample intervals were based on lithology and were generally 5 ft in mineralized zones. Zones identified by the logging geologist as being waste zones were not sampled. Sample intervals could be shorter or slightly longer at lithological contacts and through fault zones. Lithological contacts are generally sharp and recognizable.

The core was split longitudinally using a hydraulic core splitter. Half of the core was placed in a bag for analysis and the remaining half retained for geological reference. Following sample collection, the samples were delivered to the sample processing facility located in the mill facility. Preparation of the split core samples included overnight drying and subsequent crushing and pulverizing. The entire crushed and dried sample was then passed through a cone crusher, homogenized and split using a Jones splitter to a 100 gram (g) sample. Reject material was placed in envelopes and labeled for storage. From the 100 g sample, 10 g was delivered to the on-site lab for X-ray fluorescence (XRF) analysis. The grain size of the 90 g of remaining sample was further reduced using a shatterbox swing mill. A split of the pulverized material was placed in sample envelopes and delivered to the Mountain

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Pass Lab. All pulp and coarse rejects were packaged and labeled. After analysis the pulp and coarse rejects were returned to the geology department for onsite storage.

SRK was not able to independently verify or observe the sampling methods employed during the historical drilling campaigns and has relied on verbal and written descriptions of the processes by former employees of Molycorp and its predecessors. SRK reviewed drill logs, sample summary sheets, a limited number of coarse and pulp rejects and remaining drill core. The remaining drill core is stored on site and is organized by drillhole and interval. Coarse and pulp rejects are no longer available on site.

SRK conducted a random inspection of the historical sample preparation area and core in the storage areas from the various major drilling programs and is of the opinion that sample handling, sample preparation and storage of core and rejects meets current industry accepted practices.

8.1.2 Sampling 2009-2011

The 2009 to 2011 drilling programs include photographs of core, a system of marking sample intervals on the core boxes, a sample numbering system and record-keeping for all sample intervals in the drill log.

Sampling procedures include:

• A written record of the sample collected

• Marking the sample interval on the core box

• Identifying the sample interval and box interval on the inside top of the box

• Photographing the core as both dry and wet core and core box top

• Splitting of the core lengthwise using a hydraulic press

• Placing the split core into a pre-labeled sample bag

• Inserting core blocks at the beginning and end of the removed core

• Inserting a lath cut to the sample interval as a space keeper in the core box

Sample numbers were generated using a combination of the drillhole identification and from-to sample interval. Control samples were placed in the sample stream with similar numbers using a drillhole and interval to be unrecognizable to the laboratory. The sample interval used for control samples was beyond the total depth of the drillhole to eliminate confusion with an actual sample. This was noted on the sample log to avoid future confusion on total depth of drillholes.

8.1.3 Sampling 2021

Procedures of sampling 2021 drilling cores are identical to the procedures used in 2009-2011. Core samples were collected by MP Materials’ geologists, logged, photographed, split, and provided to the on-site lab for preparation and analysis.

8.2 Laboratory Analysis

There were various analytical procedures used by MP Material’s predecessors for sample preparation and analytical methods. Historically, quality assurance and quality control (QA/QC) samples were not inserted into the sample stream as part of the drilling programs.

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There were two types of analytical techniques used for measuring TREO at the Project:

• Gravimetric methods

• X-ray fluorescence (XRF)

Results for rare earths were typically reported as percent TREO.

The analysis for the drilling data in the existing assay database was obtained primarily by XRF analysis.

8.2.1 Note on Assay Terminology

For many rare earth projects, laboratory results typically include assays for all the individual rare earth oxides as well as for Y₂O₃ which is not considered a rare earth oxide but is geochemically similar and is often associated with heavy rare earth oxides. The exact grouping of individual oxides into light and heavy categories is not consistent from one project to another.

Mountain Pass is considerably enriched in light rare earth oxides (“LREO”) compared with heavy rare earth oxides and Yttrium (“HREO+Y”), due to the predominance of bastnaesite whose mineral structure favors inclusion of lighter rare earth elements. The Mountain Pass assay suite was limited to the lighter rare earth oxides, specifically La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, and Sm₂O₃ and these were routinely summed together and reported as a single value representing the sum of the five individual oxide assays. Therefore, for the Mountain Pass project, the grades entered into the drillhole database as “LnO” or “REO” and presented in this report as “TREO” represent the sum of La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, and Sm₂O₃.

Many rare earth projects discuss LREO or HREO+Y ratios by expressing one group as a percentage of the sum (LREO+HREO+Y) and may refer to this summed assay value as TREO or TREO+Y; however, this is not the case for Mountain Pass.

Specifically, the definition of the term TREO in this report is different from the same term typically used when discussing other projects. In this report, TREO is the sum of La₂O₃, CeO₂, Pr₆O₁₁, Nd₂O₃, and Sm₂O₃ and it excludes the heavier rare earth oxides and yttrium oxide.

8.2.2 Historical Analyses

Prior to 1970, Molycorp used a gravimetric method for samples from the drilling and sampling programs. The gravimetric method determined Re₂O₃% and was reported as TREO%. In this method, approximately 0.5 to 1.0 g of sample was dissolved through heating in a mixture of perchloric acid (HClO₄) and hydrogen peroxide (H₂O₂). The rare earths were then isolated in two precipitation and dissolution steps using organic solvents and inorganic rinses. The first step involved using phenolphthalein and NH₄OH and the second used oxalic acid. This procedure separated the TREO and thorium from iron, aluminum, uranium, titanium, phosphate, manganese, alkaline and alkali earth metals and other divalent cations. The final filtered precipitate of RE-oxalate was then ignited at 900 to 1,000°C and when cooled weighed as total Re₂O₃ (Jennings, 1966). SRK does not know the detection limit for this technique.

8.2.3 Current Analytical Practices

Currently, the on-site lab uses XRF and Inductively Coupled Plasma (ICP) techniques for determination of individual rare earth species and reports the analysis as individual and TREO.

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Laboratory equipment at the on-site laboratory includes:

• One Philips PW2404 x-ray spectrometer XRF with a PW2450 VRC sample changer capable of running up to 150 samples per day (the lab is currently capable of prepping 50 fusion disks per day)

• One X’Pert PRO X-ray Diffraction (XRD) PANalytical

• One Perkin and Elmer Atomic Absorption Spectrometer (AAS)

• Two Ultima2 Inductively Coupled Plasma Atomic Emission spectrometers (ICP-AES) each capable of 100 samples per day

• One Agilant Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) with an Agilant 7500cc Octopole Reaction System capable of speciation that can analyze 600 samples per day

Table 8-1 presents the detection limits for the oxides and TREO parameters.

Table 8-1: Oxides and TREO Detection Limits, Mountain Pass Laboratory

	Oxide	P2O5	ThO2	SiO2	Fe2O3	MgO	CaO	SrO	BaO
	Limit (%)	0.05	0.01	0.05	0.05	0.05	0.05	0.05	0.05
	TREO	TREO	CeO2	La2O3	Pr6O11	Nd2O3	Sm2O3
	Limit (%)	0.1	0.03	0.03	0.02	0.02	0.02

Source: SRK, 2012

8.2.4 2009 and 2010 Samples

Drill samples for the 2009 and 2010 campaigns were analyzed at both the Mountain Pass Laboratory and at SGS Minerals in Lakefield, Ontario, Canada. SGS Minerals has ISO/IEC 17025 accreditation.

Quality control samples included:

• Field blanks (roadside marble and scoria grab samples)

• Pulp blanks prepared from purchased silica sand

• Field duplicates (i.e., two splits of RC cuttings collected at the drill rig)

• Coarse reject duplicates

• Pulp duplicates

• A pit standard (pulp prepared by Mountain Pass)

8.2.5 2011 Samples

The analysis for the 2011 drilling program completed by Molycorp were analyzed at Actlabs in Ancastor, Ontario, Canada using the Code 8 Rare Earth Element Assay Package. In this package, the analysis is conducted using a lithium metaborate/tetraborate fusion followed by dissolution in acid and analysis by ICP-MS. Detection limits for this technique are shown in Table 8-2. Actlabs has ISO/IEC 17025 accreditation.

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Table 8-2: Oxides and Element Detection Limits, Actlabs Laboratory

Oxide or Element	Detection  Limit	Element	Detection  Limit	Element	Detection  Limit	Element	Detection  Limit
Al2O3	0.01%	Be	1 ppm	Rb	2 ppm	La	0.1 ppm
CaO	0.01%	Bi	0.4 ppm	Sb	0.5 ppm	Ce	0.1 ppm
Fe2O3	0.01%	Co	1 ppm	Sc	1 ppm	Pr	0.05 ppm
K2O	0.01%	Cr	20 ppm	Sn	1 ppm	Nd	0.1 ppm
MgO	0.01%	Cs	0.5 ppm	Sr	2 ppm	Sm	0.1 ppm
MnO	0.001%	Cu	10 ppm	Ta	0.1 ppm	Eu	0.05 ppm
Na2O	0.01%	Ga	1 ppm	Th	0.1 ppm	Gd	0.1 ppm
P2O5	0.01%	Ge	1 ppm	Tl	0.1 ppm	Tb	0.1 ppm
SiO2	0.01%	Hf	0.2 ppm	U	0.1 ppm	Cy	0.1 ppm
TiO2	0.001%	In	0.2 ppm	V	5 ppm	Ho	0.1 ppm
LOI	0.01%	Mo	2 ppm	W	1 ppm	Er	0.1 ppm
Ag	0.5 ppm	Nb	1 ppm	Y	2 ppm	Tm	0.05 ppm
As	5 ppm	Ni	20 ppm	Zn	30 ppm	Yb	0.1 ppm
Ba	3 ppm	Pb	5 ppm	Zr	4 ppm	Lu	0.04 ppm

Source: Modified from Actlabs fee schedule (http://www.actlabs.com/files/Canada_2012.pdf, 2012

8.2.6 2021 Samples

A relatively small subset of the database is comprised of samples taken during 2021 geotechnical drilling. These samples function for two purposes, primarily as additional information to characterize select interceptions of mineralization, and secondly as verification of the sample prep and analysis methodology employed by the Mountain Pass laboratory.

8.3 Quality Control and Quality Assurance

8.3.1 Historical QA/QC

During the drilling programs at the Project, which were conducted prior to 1992, there was no QA/QC in place that included the regular insertion of standards, blanks, and duplicates into the sample stream. SRK located a limited number of laboratory printouts but no analytical certificates. Within the printouts, SRK found a limited number of re-analyses, but these were not systematic, appeared to be confirmation of higher grades and did not represent the entire spectrum of analytical results. Current laboratory personnel report that instrument QA/QC was in place at the on-site laboratory during these drilling programs, but no records are available.

The pre-1992 drilling comprises more than half of the drilling used in the resource model. The uncertainty that results from the lack of QA/QC is counteracted by the production reconciliation presented in this report.

8.3.2 2009-2010 Campaign QA/QC Program

The infill drilling program conducted in 2009 through 2010 used both the Mountain Pass laboratory and SGS Lakefield for sample assay. Figure 8-1 illustrates the assay results returned for the pit standard. The pit standard was prepared and homogenized by Molycorp and was not subjected to a round robin assay study which would normally be completed to ‘certify’ the standard material; nevertheless, the results were quite precise, and both laboratories were broadly in agreement with each other with Mountain Pass laboratory returning slightly lower grades on average than SGS laboratory.

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Source: SRK, 2019

Figure 8-1: 2009 Through 2010 Pit Standard Assays

A number of duplicate samples were submitted during the course of the program to assess the repeatability of sample assays both for field duplicates and for pulp duplicates. Figure 8-2 illustrates the results, generally both field and pulp duplicates compare closely, the half average relative difference for each dataset is up to +/-17% and up to +/-6% respectively. This shows that the mineralization is reasonably homogeneous within the drill core and that there is only limited potential for sampling error.

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Source: SRK, 2019

Figure 8-2: 2009 Through 2010 Duplicates

8.3.3 2011 Campaign QA/QC Program

The 2011 drilling program included the insertion of blanks and duplicates but no standards. The prior standard samples were depleted during the 2010 drilling campaign. Blanks, standards, and duplicates are part of an industry best practice drilling program and are used to independently check precision and accuracy during analysis.

SRK was not provided with the QA/QC data from the 2011 drilling program. As a result, SRK has not reviewed this QA/QC data and cannot comment.

8.3.4 2021 Campaign QA/QC Program

The 2021 drilling included a series of field duplicate analyses and four blank insertions into the sample stream. No standards (certified reference materials) were inserted to test laboratory precision. Duplicates were collected as quarter core from the remaining half not sent for analysis as the primary sample. One quarter was provided to the Mountain Pass lab to test against the primary half core sample. The second quarter was sent to ALS Minerals in Tucson, AZ for processing and ALS Minerals Vancouver for analysis. While the comparison for the duplicates within the MP lab (Figure 8-3) show excellent agreement, the comparison for the duplicates submitted to ALS (Figure 8-4) appear relatively poor, with significant deviations in grade from the original Mountain Pass sample. In SRK’s opinion, this likely demonstrates differences between laboratories in terms of preparation/analytical methodology.

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18.00 0.00 0.00 2.00 4.00 6.00 5.00 10.00 Original 15.00 20.00 ... Linear (Duplicate TREO) 10.00 Duplicate 8.00 12.00 16.00 14.00 Duplicate TREO

Source: SRK, 2021

Figure 8-3: 2021 Field Duplicate Analyses – MP Materials Lab

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16.00 14.00 12.00 10.00 8.00 6.00 4.00 2.00 0.00 0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 -2.00 MP REO ALS Linger (REO ALS)

Source: SRK, 2021

Figure 8-4: External Duplicate Analyses – MP vs. ALS

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9 Data Verification

This section summarizes data verification performed by SRK in relation to information supporting the mineral resources.

9.1 Re-Assaying Program

In 2009, SRK conducted a review of historical sample preparation and analytical procedures. The result of this review was to perform a check assay program. Sample pulp and reject material was largely discarded from previous owners so SRK utilized archived split core stored onsite.

For this check assay program, samples were shipped to then prepared at SGS Minerals preparation laboratory located in Elko, Nevada, USA. (SGS Elko). The primary analytical laboratory used for this program was SGS Minerals (SGS Minerals) located in Lakefield, Ontario, Canada and approximately 10% of these check samples were also analyzed on site at the internal Mountain Pass Laboratory.

9.1.1 Procedures

The 2009 sample check program included re-analysis of approximately 1% of the historical assay database results. The program included the following sample types and numbers:

• 108 half-core samples with original assay results between 0.18% to 16.30% TREO

• 10 site-specific standard samples based on two samples of known TREO content

• 10 blind duplicates

• 5 blank samples

SRK selected random duplicate samples from sample intervals within the database that covered a range of analytical results from 0.18% TREO to 16.30% TREO. Since these duplicate samples are retained half split core, they are effectively field duplicates. Of the 108 core samples, 66 core samples had historical assay results between 3.00% and 11.00% TREO. The remaining 42 core samples had historical assay results between 0.18% and 2.99% or 11.01% and 16.30% TREO.

Standards and blanks were site specific. The site-specific standards are non-certified and were created by the on-site laboratory from a pit sample and a high-grade sample from the Birthday claim. The blank material was a non-mineralized sample collected at the Mountain Pass site by SRK.

SRK directed SGS Elko to prepare ten duplicates from the pulverized samples and to give them unique sample numbers. The duplicates were prepared and inserted into the sample stream prior to shipping to the SGS Minerals laboratory for analysis. Ten pulverized splits of the core samples were also sent back to the on-site laboratory for comparative analysis. The pulverized splits are considered pulp duplicates, with an allowed a ±10% error.

In addition to the external SRK quality control (QC) samples, SGS Minerals included their internal laboratory QC sampling including one blank, one sequential duplicate (i.e., a duplicate placed immediately after the primary sample) and three additional duplicates per batch at the analytical lab in Lakefield. The analysis was run in two batches, totaling two blanks, two in-line duplicates and six duplicates in addition to the external QC samples from SRK. Calibration standards were provided by the Mountain Pass Laboratory to insure similar analytical sensitivity for both labs.

For the onsite Mountain Pass laboratory, site technicians inserted two duplicates and one standard in the ten samples analyzed onsite.

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For specific gravity (SG) QC, ten samples were selected from the core samples and sent to ALS in Reno, Nevada U.S.A for SG measurements. SG is further discussed further in Section 11.5.

9.1.2 SGS Check Assay Sample Preparation

Sample preparation for the check analysis was completed at SGS Elko. The preparation technique used was SGS Minerals code PRP90, which used the following procedures:

• The sample was dried at 100°C for 24 hours.

• The sample was crushed to 90% passing a 2 millimeter (mm) (10 mesh) screen.

• The sample was split using a riffle splitter to 250 g.

• The 250 g split was placed in a vibratory mill and pulverized until 85% passed a 75-micron (200 Mesh) screen.

• The coarse reject was retained and returned to the client for any future analysis.

The sample was then shipped to the SGS Minerals laboratory for X-Ray Fusion (XRF) analysis (SGS Minerals, 2009).

9.1.3 SGS Check Assay XRF Procedures

SGS Minerals worked closely with the Mountain Pass Laboratory to identify the appropriate method for preparing fusion discs for the XRF to ensure that both labs used similar procedures for TREO analysis. A 0.2 g to 0.5 g pulp sample is fused with 7 g of a 50/50 mixture of lithium tetraborate and lithium metaborate into a homogenous glass disk. This is then analyzed using a wave dispersive XRF (WDXRF). Loss on ignition at 1000°C is determined separately using gravimetric techniques and is part of the matrix correction calculation. These calculations are performed by WDXRF software (SGS, 2009). This method is accredited with the Standards Council of Canada (SCC) and conforms with the requirements of ISO/IEC 17025 (SGS, 2009).

The analyses performed for the SRK study included SGS Minerals control quality measures, which are used to monitor and control metallurgical or manufacturing processes. They are analyzed individually for better quality output. The oxides analyzed and their detection limits are listed in Table 9-1. The analytical work included Loss on Ignition (LOI) as a separate analysis.

Table 9-1: Oxides Analyzed with Detection Limits

	Oxide	Limit (%)		Oxide	Limit (%)		Oxide		Limit (%)
	Whole Rock Analysis
	SiO2		0.01	Na2O		0.01		CaO		0.01
	Al2O3		0.01	TiO2		0.01		MgO		0.01
	Fe2O3		0.01	Cr2O3		0.01		K2O		0.01
	P2O5		0.01	V2O5		0.01		MnO		0.01
	Rare Earth Oxide Analysis
	La2O3		0.01	CeO2		0.02		Nd2O3		0.02
	Pr6O11		0.02	Sm2O3		0.03		BaO		0.02
	SrO		0.02	ThO2		0.01

Source: SRK, 2012

9.1.4 Analysis of Light Rare Earth Oxide Distribution

Starting in 2009, Molycorp expanded the assay method to include the individual rare earths present in each sample. During the 2009 in-fill and 2010 condemnation drilling campaigns, SRK selected

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403 samples for the assay of light rare earth elements (i.e., lanthanum, cerium, praseodymium, neodymium and samarium). Table 9-2 presents a statistical summary of the light rare earth element results.

Table 9-2: Light Rare Earth Oxide Distribution Statistics: 2009 and 2010 Analyses

	Statistic	La2O3		CeO2		Pr6O11		Nd2O3		Sm2O3
	Number of Samples		403		403		403		403		403
	Mean Fraction of TREO		0.325		0.497		0.043		0.121		0.009
	Standard Deviation		0.026		0.021		0.003		0.012		0.002
	Coefficient of Variance		0.079		0.042		0.075		0.095		0.238
	Minimum		0.26		0.44		0.02		0.09		0.01
	Maximum		0.41		0.61		0.05		0.17		0.02
	Abs Diff (Min – Max)		0.151		0.167		0.028		0.080		0.015

Source: SRK, 2012

Standard deviation and associated coefficient of variance indicate a relatively narrow range of variability suggesting that the light rare earth distribution is consistent. SRK has verified the QA/QC aspects of the 2009/2010 data set and is of the opinion that the protocols in place during this period meet or exceed industry best practices.

In 2011, Molycorp completed an expanded assay program using a combination of existing core samples and additional drilling in the resource area. Molycorp conducted an additional 395 assays for individual light rare earths. Table 9-3 presents the summary statistics for this assay program.

Table 9-3: Light Rare Earth Oxide Distribution Statistics: 2011 Analyses

	Statistic	La2O3		CeO2		Pr6O11		Nd2O3		Sm2O3
	Number of Samples		395		395		395		395		395
	Mean Fraction of TREO		0.327		0.500		0.043		0.121		0.009
	Standard Deviation		0.019		0.010		0.003		0.012		0.002
	Coefficient of Variance		0.060		0.019		0.077		0.101		0.242
	Minimum		0.27		0.46		0.02		0.09		0.01
	Maximum		0.37		0.54		0.05		0.16		0.02
	Range (Min – Max)		0.102		0.075		0.028		0.070		0.016

Source: SRK, 2012

Similar to the 2009 and 2010 statistical summary, the 2011 analyses corroborate the relative light rare earth oxide distribution as a function of TREO. The standard deviation and associated coefficient of variation represent a wider range of variability but still suggest a narrow overall range for light rare earth distribution and that the data are consistent.

SRK combined the 2009 through 2011 light rare earth assays and calculated summary statistics for each light rare earth. Table 9-4 presents the results of this combined analysis of light rare earths.

Table 9-4: Light Rare Earth Oxide Distribution Statistics: 2009, 2010 and 2011 Analyses

	Statistic	La2O3		CeO2		Pr6O11		Nd2O3		Sm2O3
	Number of Samples		798		798		798		798		798
	Mean Fraction of TREO		0.326		0.499		0.043		0.121		0.009
	Standard Deviation		0.023		0.015		0.003		0.012		0.002
	Coefficient of Variance		0.069		0.031		0.076		0.098		0.240
	Minimum		0.258		0.444		0.022		0.092		0.005
	Maximum		0.410		0.611		0.051		0.171		0.021
	Range (Min – Max)		0.151		0.167		0.028		0.079		0.016

Source: SRK, 2012

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The combined dataset of 798 individual assays provides a robust basis to define the distribution of light rare earths in the target carbonatite mineral, bastnaesite.

SRK examined the individual assay parameters for the 2009 and 2010 drilling campaigns. Table 9-5 presents the results of this examination. The mean TREO% of this dataset is 7.96%, indicating that the majority of assayed samples are likely above the 5% TREO cut-off grade. Standard deviations are greater than 50% of the mean estimates. SRK notes that as mean TREO grades are reduced in future mining, it is recommended that the applied LREO applied concentrations are revised and evaluated to whether adjustments are warranted.

Table 9-5: Light Rare Earth Oxide Assay Statistics: 2009 and 2010 Analyses

	Statistic	La2O3		CeO2		Pr6O11		Nd2O3		Sm2O3
	Length (ft)		1,972		1,972		1,972		1,972		1,972
	Number		395		395		395		395		395
	Mean Grade (%)		2.652		3.970		0.336		0.932		0.067
	Standard Deviation		1.69		2.35		0.19		0.51		0.03
	Coefficient of Variance		0.637		0.593		0.579		0.546		0.511
	Minimum Grade (%)		0.80		1.35		0.11		0.35		0.03
	Maximum Grade (%)		7.81		10.84		0.95		2.68		0.21
	Abs Diff Grade (%)		7.01		9.49		0.85		2.33		0.18

Source: SRK, 2012

9.1.5 Analysis of Heavy Rare Earth Oxide Assays

Based on a limited re-assaying program of 210 five ft composite samples from eight of the 2009 Mountain Pass drillholes, the HREO+Y subtotal expressed as a proportion of LREO+HREO+Y is on average 0.8% in the high-grade samples (TREO>5%), 1.8% in low to medium grade samples (TREO 2% to 5%) and 2.2% in the lowest grade samples (TREO<2%). Table 9-6 summarizes the results per element for the three grade categories.

SRK notes that while this data shows the presence of these heavy rare earths in the Mountain Pass deposit, given the majority of historical sampling does not include analysis for these elements, they have been excluded from the mineral resource estimate given the uncertainty around the consistency of distribution across the deposit. Further investigation is recommended to improve the understanding and confidence in average grade distributions prior to inclusion of these elements in the mineral resource statement.

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Table 9-6: Heavy Rare Earth Summary

		Assay Grade (%)						Proportion of LREO+HREO+Y
		Grade Category						Grade Category
		>5%		2%-5%		<2%		>5%		2%-5%		<2%
	Y2O3		0.02		0.02		0.01		0.21%		0.66%		0.79%
	La2O3		2.85		0.75		0.33		33.4%		30.4%		29.1%
	CeO2		4.19		1.20		0.55		49.1%		48.8%		49.0%
	Pr6O11		0.36		0.11		0.05		4.25%		4.52%		4.67%
	Nd2O3		0.98		0.32		0.15		11.5%		13.2%		13.8%
	Sm2O3		0.07		0.03		0.01		0.86%		1.21%		1.34%
	Eu2O3		0.013		0.006		0.003		0.15%		0.24%		0.27%
	Gd2O3		0.021		0.011		0.006		0.25%		0.46%		0.53%
	Tb4O7		0.004		0.002		0.001		0.05%		0.06%		0.08%
	Dy2O3		0.006		0.004		0.002		0.07%		0.17%		0.20%
	Ho2O3		0.001		0.001		0.001		0.01%		0.03%		0.05%
	Er2O3		0.005		0.002		0.001		0.06%		0.08%		0.09%
	Tm2O3		0.001		0.001		0.001		0.01%		0.02%		0.04%
	Yb2O3		0.001		0.001		0.001		0.01%		0.03%		0.05%
	Lu2O3		0.001		0.001		0.001		0.01%		0.02%		0.04%
	LREO		8.46		2.41		1.10		99.2%		98.2%		97.8%
	HREO+Y		0.07		0.04		0.02		0.8%		1.8%		2.2%
	LREO+HREO+Y		8.53		2.46		1.12		100%		100%		100%

Source: Molycorp, 2009

9.1.6 Results

Statistical comparison of the analytical results for the 108 core samples with the historical assay database values indicate the datasets are broadly comparable within tolerance limits. Results for the site-specific standards and duplicate samples were also within acceptable confidence limits.

There were no blank failures indicating that there was no cross contamination during sample preparation. However, two failures were observed in the low-grade standard in the 2009 and 2010 QA/QC analysis at the Project. Only one high grade standard was inserted in the sample stream due to delays in creating this sample. Both standards performed lower than the expected value and the nine low grade standard analyses suggest instrument drift, based on a consistent downward slope in the graph over time.

In addition, one of the standards that failed was within a group of samples that showed acceptable correlation with the original sample. The standard failure may be due to failure to adequately determine the accepted mean and standard deviation of the standard samples. Table 9-7 lists the standards with expected analytical values and Figure 9-1 shows the results of the standards.

Table 9-7: Standards with Expected Analytical Performance

		Maximum TREO (%)		Median TREO (%)		Minimum TREO (%)
	Pit Standard		6.50		5.91		5.32
	Birthday Standard		24.86		22.60		20.34

Source: SRK, 2012

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Pit Standard 1.00 +10 (-20) 6.50 6.00 591 5.00 5.32 100 -10(-20) 8 9 10 012 Birthday Standard +10% (-20) 24.86 24 23 22.60 (%) 22 21 10(-20) 24.34

Source: SRK, 2012

Figure 9-1: Results of Standard Analysis

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The Mountain Pass pulp duplicates showed satisfactory agreement with the SGS Lakefield original analyses being within ±10% with one failure. The blind pulp duplicate assay value pairs analyzed by SGS were all within ±10% of each other. These results are shown in Figure 9-2.

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SGS Originals. SGS Duplicate 10% 1 pales SUS Original (RFU5) Mt. Pass Duplicate vs. SCS Duplicate -10% Mt. Pass Duplicate (Re0 %)

Source: SRK, 2012

Figure 9-2: Results of Pulp Duplicate Analysis

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Overall, the historical Project analyses in the resource database are on average lower than the corresponding SGS Minerals analyses and the present-day Mountain Pass Laboratory analyses. This is shown in the scatterplot provided in Figure 9-3. SRK notes that the observed scatter between labs from this program is similar to the 2021 duplicate core samples submitted to ALS, indicating that there are likely minor differences in processing of samples between labs. It is SRK’s opinion that these differences are considered immaterial as it applies to confidence of mineral resources.

Source: SRK, 2012

Figure 9-3: Results of Field Duplicate Analysis

9.2 Opinion on Data Adequacy

It is SRK’s opinion that the database of geological and analytical data used to determine and classify mineral resources is appropriate to application of confidence categories.

The duplicate pulps assayed at Mountain Pass during this verification exercise show that assays generated by the internal Mountain Pass Laboratory provide a satisfactory comparison with the external laboratory of SGS Lakefield. SRK concludes that assay results from the 108-half core duplicate samples show minor scatter and variations which are partly due to the differences in grade from one half of the core to the other and partly due to laboratory precision. This conclusion is based upon the 2021 duplicate analysis as well. It appears that the historical samples which were prepared on site and assayed at the Mountain Pass Laboratory 20 years ago returned lower assay grades than those returned by SGS Lakefield based on the field duplicate analysis.

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Overall, average grades for field duplicates submitted to ALS for the 2021 samples returned a lower grade of 3.4% TREO vs. the MP lab at 3.8%. Given the limited duplicate data set and the nature of there being no consistent bias observed, SRK notes that this remains unresolved at the time of this report. SRK strongly recommends that MP investigates the source of the variance in the duplicates from the 2021 sampling.

The production reconciliation has shown that the MRE model is generally reliable although demonstrably lower grade than the grade control data. The MRE grades are expectedly smoother than those in the grade control data which suggests opportunity to potentially improve the delineation of higher and lower grade populations in the resource model during future updates and iterations.

Overall, SRK is of the opinion that the historical analytical data in the database can support a level of confidence commensurate with long term resource estimation. Uncertainties in the underlying quality of the analytical data accounted for in mineral resource classification and compensated by the fact that Mountain Pass is an operating mine with ongoing production and reconciliation to support the long-term resource.

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10 Mineral Processing and Metallurgical Testing

10.1 Background

MP Materials mines ore from the open pit, transports the ore to a primary crushing/stockpile facility and transports the ore to the mill. At the mill, the crushed material is ground further with a ball mill and conveyed via a slurry pipeline to the flotation plant to separate the bastnaesite from the gangue minerals. The primary product of the flotation process is a bastnaesite concentrate, which is filter dried and then transported to customers for sale or fed to the on-site separations facility. The discussion in Sections 10.2 and 10.3 have been prepared by SRK. MP Materials has determined SRK meets the qualifications specified under the definition of qualified person in 17 CFR § 229.1300.

MP Materials has recommissioned a rare earths separations facility that is ramping up, with full capacity expected to be achieved by the end of 2024. The separations facility allows the Company to separate the bastnaesite concentrate into four saleable products (PrNd oxide, SEG+ oxalate, La carbonate, and Ce chloride). The discussion of the separations facility in Section 10.4 has been prepared by SGS. MP Materials has determined SGS meets the qualifications specified under the definition of qualified person in 17 CFR § 229.1300.

10.2 Flotation Studies Versus Ore Grade

During the later years of mining operations at Mountain Pass, the ore grade is expected to decline. To assess TREO (total rare earth oxide) recovery from lower-grade ore, MP Materials conducted rougher flotation tests on ore samples over a grade range from 1.86% to 8.10% TREO using standard concentrator test conditions. Each test composite was prepared and assayed for the full suite of analyses shown in Table 10-1.

Rougher flotation tests were conducted on each test composite for a total retention time of eight minutes with concentrates collected at timed increments, which allowed the evaluation of TREO recovery versus concentrate grade. The results of these rougher flotation tests are summarized in Table 10-2.

TREO recovery versus concentrate grade was plotted for each test and is shown graphically in Figure 10-1 along with the corresponding grade versus recovery equation that was developed for each test composite. MP Materials has established from plant experience that a rougher flotation concentrate containing 25% TREO is required in order to produce a final upgraded cleaner concentrate containing 60% TREO.

Table 10-3 shows interpolated TREO recoveries for each test composite at a fixed 25% TREO rougher flotation concentrate grade. TREO recovery into the rougher concentrate increased from 29.0% to 83.4% as the feed grade increases from 1.9% to 8.1% TREO. Additionally, MP Materials reports that the concentrator recovers, on average, 83.1% of the TREO contained in the rougher flotation concentrate into a final cleaner flotation concentrate containing 60% TREO. As shown in Table 10-3, estimated overall REO recovery into a cleaner flotation concentrate containing 60% TREO increases from 24.1% to 69.3% as the ore grade increases from 1.9% to 8.1% TREO. A TREO recovery versus ore grade equation was developed by MP Materials based on these results.

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Table 10-1: Head Analyses for Grade Range Test Composites

Composite	TREO (%)		La2O3 (%)		CeO2 (%)		Pr6O11 (%)		Nd2O3 (%)		MnO (%)		Fe2O3 (%)		Al2O3 (%)		BaO (%)		CaO (%)		SiO2 (%)		MgO (%)		P2O5 (%)		SrO (%)
2019 test 3~5%		3.22		1.00		1.61		0.07		0.23		0.30		6.11		6.63		9.60		13.13		28.12		3.32		0.52		2.60
2020 test 3~5%		3.92		1.25		2.02		0.12		0.34		0.30		5.94		5.28		9.57		16.36		22.04		3.51		0.63		3.24
2020 test 5~7%		5.65		1.84		2.92		0.20		0.62		0.31		5.17		5.22		9.99		15.02		23.10		2.71		0.48		3.91
2020 test 7~8%		7.13		2.33		3.68		0.28		0.88		0.30		4.63		5.41		9.74		13.42		24.57		1.92		0.32		4.23
2020 test > 8%		8.10		2.70		4.18		0.33		0.89		0.45		3.46		2.03		15.70		18.96		9.85		4.26		0.51		1.99
2021 test 2%		1.86		0.57		0.93		0.07		0.12		0.17		4.55		10.56		3.99		7.93		46.23		3.48		0.31		0.73
2021 test 2.5%		2.70		0.82		1.35		0.10		0.22		0.20		4.40		9.29		5.54		8.78		41.52		3.42		0.35		0.98
2021 test 3%		3.22		0.98		1.61		0.13		0.29		0.22		4.29		8.55		6.49		9.98		37.18		3.75		0.38		1.00
2021 test 3.5%		3.46		0.99		1.73		0.02		0.39		0.26		4.67		9.57		7.09		11.00		31.98		4.57		0.40		1.42

Source: MP Materials, 2021

Table 10-2: Cumulative Rougher Flotation Concentrate Grade and Recovery Versus Ore Grade

Ore Grade  REO %	Cumulative Ro Conc Grade (TREO%)				Cumulative TREO Recovery (%)
	Ro Conc-1	Ro Conc-2	Ro Conc-3	Ro Conc-4	Ro Conc-1	Ro Conc-2	Ro Conc-3	Ro Conc-4
1.86	28.0	23.4	20.0	16.9	18.7	33.5	37.3	38.7
2.70	29.6	26.8	24.2	21.7	21.2	35.0	39.1	40.5
3.22	31.5	28.2	25.4	22.6	21.7	36.8	41.0	42.6
3.46	34.4	29.8	27.9	24.8	28.5	41.6	44.8	46.2
3.92	33.0	23.5	20.3	18.4	47.6	64.5	69.7	71.4
5.65	36.1	31.0	28.1	24.8	60.9	71.9	74.9	76.2
7.13	43.9	33.1	30.3	26.1	62.6	77.2	79.8	81.8
8.10	38.2	31.2	28.5	25.5	59.4	77.9	81.6	83.3

Source: MP Materials, 2021

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Source: MP Materials, 2021

Figure 10-1: TREO Rougher Flotation Recovery versus Concentrate Grade for Different Feed Grades

Table 10-3: Estimated Rougher and Cleaner Flotation REO Recovery ⁽¹⁾

Head Grade  TREO (%)	Rougher Concentrate		Estimated Cleaner Concentrate
	TREO (%)	TREO Recovery (%)	TREO (%)	TREO Recovery (%) (2)
1.86	25	29.0	60	24.1
2.70	25	38.8	60	32.2
3.22	25	42.3	60	35.1
3.46	25	46.3	60	38.5
3.91	25	62.3	60	51.7
5.65	25	76.1	60	63.2
7.13	25	82.2	60	68.3
8.10	25	83.4	60	69.3

Source: MP Materials, 2021

⁽¹⁾ Based on 25%TREO Rougher Concentrate Grade and 60% TREO Cleaner Concentrate Grade

⁽²⁾ Plant cleaner flotation unit recovery: 83.1%

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10.3 Concentrator Recovery Estimate

The TREO recovery versus ore grade relationship developed by MP Materials based on the results of rougher flotation tests over a range of feed grades is shown on Figure 10-2. TREO recovery versus ore grade is expressed by the following relationship which is capped at 70% recovery to conservatively reflect actual plant performance:

Y = -0.0431x⁵ + 1.2761x⁴ – 14.415x³ + 75.427x² – 169x + 159.4

Where:

Y = TREO recovery % into the cleaner flotation concentrate at a grade of 60% REO

x = Ore grade: REO%

At ore grades less than 2% TREO this recovery relationship is not valid and begins to estimate incrementally higher REO recoveries. To address this issue, SRK has interpolated REO recovery at 22% for the ore grade increment of 1.5% to 2.0% TREO and zero % recovery for ore grades less than 1.5% TREO. SRK is of the opinion that the data relied upon is adequate for the purposes of estimating concentrator recoveries across the anticipated range of mill feed grades.

Source: MP Materials, 2021

Figure 10-2: TREO Recovery to Cleaner Flotation Concentrate versus Feed Grade

10.4 Separation of Individual Rare Earths

The findings put forth by SGS are based on decades of process data, implied results from MP Materials’ current customers, plant data from the same assets operating between 2012-2015, bench

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data, and pilot data. For the purposes of this report, it was assumed that the separations facility ramp up will follow a Type 2 McNulty curve, resulting in feeding 100% of concentrate production into the facility by 2025.

10.4.1 Metallurgical Testwork

MP Materials has conducted extensive pilot testing to both generate data to design circuits and to confirm existing legacy data. There are 11 primary processes that make up the separations (“Stage 2”) operation; they are outlined in Figure 10-3 below.

Process	Data Source	Analytical Results
1 Concentrate Drying & Roasting	Historical Data (1965-1998); customer data; pilot data (small/large scale)	MP & 3rd Party Laboratories
2 Leaching Impurity Removal	Historical Data (1965-2011); 3rd party lab; pilot data (small/large scale)	MP & 3rd Party Laboratories
3 HREE/LREE Separation	Plant data (2012-2015); pilot data (small/large)	MP & 3rd Party Laboratory
4 PrNd Separation	Plant data (2012-2015); pilot data (small scale)	MP Laboratory
5 PrNd Finishing	Plant data (2012-2015); 3rd party lab testing; pilot data (small scale)	MP & 3rd Party Laboratories
6 La Finishing	Plant data (2012-2015); 3rd party lab testing; pilot data (small scale)	MP & 3rd Party Laboratories
7 Ce Finishing	Plant data (2012-2015); pilot testing (small scale)	MP, 3rd Party Laboratory, Customer qualification
8 SEG+ Finishing	Plant data (2012-2015); pilot data (small scale); interference testing	MP Laboratory; 3rd Party Laboratory; Customer Data
9 Brine Recovery, Treatment, Crystallizing	Plant data (2012-2015); pilot data (small scale); vendor testing/engineering	MP & 3rd Party Laboratories

Source: MP Materials, 2021

Figure 10-3: Primary Processes for Stage 2 Operation

Details of the test work performed are as follows.

Concentrate drying and roasting: roasting of bastnaesite concentrate began at Mountain Pass in 1965 or 1966. Roasting of bastnaesite is known to convert the carbonates into oxides with the salutary effect of converting much of the trivalent cerium to the tetravalent state, which is largely insoluble. The roasting conditions are critical to leach recovery. Consequently, roasting is a most important thermal step that will allow for economical downstream rare earth processing. Legacy records from the multi-hearth furnace (that remains onsite) suggested a roasting temperature of approximately 600°C. To confirm these figures, MP Materials conducted initial scoping studies of different roasting temperatures and roasting residence times at Hazen Research. The roasted concentrate was then leached at various temperatures and acid consumption levels to confirm recoveries of trivalent rare earth elements (REEs) and rejection of cerium. This testing was then scaled up by sending at least 5 st of concentrate to multiple outside labs and tolling facilities. These organizations performed larger scale roasting exercises using their pilot equipment. These samples were sent to SGS Lakefield for further confirmatory testing. These tests confirmed the optimal process conditions. Lastly, an approximately 2 st batch of roasted concentrate was leached at MP Materials’ Cerium 96 plant in two large reactors to confirm the scalability of the results. Subsequent smaller scale leach tests using the same roasted concentrate have been performed to optimize the timing and temperature of HCl to further enhance PrNd recovery and Ce rejection.

Leaching: given the interconnectedness of roasting with the leach steps, leaching pilot studies were used to confirm both the effectiveness of the roasting conditions and the optimization of leach conditions. As mentioned above, testing was performed at several outside laboratories, and MP Materials’ pilot plant. The results were duplicated on a larger scale in MP Materials’ Cerium 96 plant. To mirror the temperature control and flexibility provided in MP Materials’ multi-stage, temperature-controlled reactors, MP Materials upgraded its small-scale leach pilot facility to incorporate better temperature control than was available in the Cerium 96 plant or at outside laboratories. This generated the best results, superior to those of previous tests. Notwithstanding, MP Materials has

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used the more conservative recovery estimates to underly its pre-feasibility study for the separations facility.

Impurity Removal: following the leach step and the removal of the cerium concentrate and insoluble impurities, the next stages initiate the removal of remaining impurities. The primary end point is the removal of iron, uranium, aluminum, and any other salts that may be partially solubilized with the potential to produce solids (i.e., CRUD – defined as interphase suspended solids or emulsions) in the solvent extraction circuits. These circuits were operated by MP Materials’ predecessor from 2012-2015. Plant data confirms that these circuits operated with few major issues. Improvements include a new thickener, filter press, and a pressure leaf filter to ensure full removal of precipitated solids induced by pH adjustment. Also, the installation of a system to add filter aid to assist in the solid-liquid separation stage of additional impurities is expected to further reduce the risk of CRUD formation in the (solvent extraction) SX circuits and improve consistent throughput. SGS Lakefield pilot tests for impurity removal and MP Materials own pilot tests confirm the ability to successfully remove sufficient iron, uranium, and dramatically reduce aluminum prior to SX. A secondary bulk extraction is then performed to remove rare earths from remaining impurities, in particular the cations Ca and Mg. Historical plant data demonstrates that this system operated largely without major complications. The removal of a significant portion of the cerium during leaching will offset the increased volumetric flow which will result from higher concentrate production. MP Materials has conducted several pilot plant runs using glass mixer-settlers to produce feed for heavy REE separations and (solvent extraction didymium) SXD pilot plant experiments to further minimize CRUD formation. All these studies have confirmed high recovery and purity of the RE-enriched preg solution.

SXH: a bulk separation of the heavy rare earths (SEG+) fraction from light rare earth element (LREE) will be performed in solvent extraction heavies (SXH). Previous plant operating experience between 2012-2015 and MP Materials’ modeling confirms that this plant is adequately sized to ensure clean separation of Sm+ from Nd while minimizing losses of Nd into Sm. The separation factor between Sm and Nd is large (aided largely by the absence of Pm in nature), so MP Materials has not performed any additional piloting on this circuit.

SXD: the SXD circuit separates a PrNd stream from the La and residual Ce in the SXH raffinate. SXD operated smoothly under the predecessor entity and sufficient data exists from the later months to conclude that once in equilibrium, the ability to make on-spec PrNd is confirmed. However, MP Materials is pursuing an additional separation in this facility involving the elimination of the need for a separate cerium removal stage.

PrNd Finishing: precipitation of PrNd from the chloride media has been piloted at SGS Lakefield as well as in MP Materials’ pilot plant. Both carbonate and oxalate experiments were conducted and analyzed for rheology, particle size, settling rate, impurities, ability to meet market product specifications, and determination of equipment sizing. The products were analyzed by a 3^rd party laboratory and MP Materials’ analytical laboratory. The finishing circuit has been designed for maximum flexibility for product precipitation and high-purity finishing based upon testing performed by MP Materials, 3^rd party laboratories, and equipment vendors.

La Finishing: lanthanum precipitation by soda ash, solid liquid separation, drying and calcining tests were conducted at 3^rd party laboratories, and in MP Materials’ pilot plant to confirm rheology, equipment sizing, and the ability to meet market specifications. The implementation of a 2-stage (countercurrent decantation) CCD solid-liquid separation circuit is anticipated to improve spent leach

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solution (SLS), minimize losses, and improve product quality. This approach was demonstrated in several pilot plant runs.

PhosFIX^™ Finishing: a multi-month pilot study conducted by MP Materials demonstrated the ability to produce a clean cerium chloride solution for sale into the water treatment market. This confirmed previous modeling studies. The laboratory data were confirmed by MP Materials’ laboratory and by mass balances. The wide range of acceptable La to Ce ratios means that little additional pilot work has been necessary.

SEG+ Finishing: MP Materials plans to use the same SEG+ finishing assets as previously employed from 2012-2015 with minimal change. Legacy plant data confirms that the equipment is appropriately sized and designed, so no additional testing was performed.

Brine Recovery, Treatment, Crystallizing: MP Materials has conducted several rounds of pilot studies taking appropriate mixtures of brine from previously operated facilities and SX pilot plant investigations to produce a representative brine. Additional flocculant testing and soda ash precipitation has been conducted in several runs to confirm the ability to perform adequate solid/liquid separation. MP Materials plans an upgrade to the brine recovery circuit, including the addition of an additional filter press (like in kind), and a pressure leaf filter as a final polishing step. These will facilitate removal of non-sodium salts, to be disposed on site, prior to sending the sodium chloride solution to the brine evaporator and crystallizer. As no material chemical changes are expected, the major focus has been on confirming adequate equipment sizing. Legacy plant data combined with SysCAD modeling confirm that there should be sufficient redundancy to handle the expected volume. A salt crystallizer is being designed to handle the expected plant flow (including an engineering factor). A conservative brine assay was provided to confirm suitability of the materials of construction as well as throughput. The existing brine evaporator ran smoothly to service the chlor-alkali plant (that is not slated for restart until a later date) and is being repositioned to optimize the crystallizer feed solution. No direct piloting of the crystallizer has been performed, though the vendor has provided a performance guarantee.

10.4.2 Representativeness of Test Samples

The Mountain Pass ore body has been consistent over 70 years of regular mining, beneficiation, and processing. The mineral resource and mineral reserve estimates presented in this Technical Report Summary forecast a similar mineralogy over the life of mine. For this reason, the pilot results are considered to be representative of the results to be expected for the deposit as a whole.

The most critical steps in the entire hydrometallurgical and separation process are the roasting and leaching steps. These steps are critical for cracking the bastnaesite mineral as well as maximizing trivalent recovery and minimizing cerium recovery that underlie the processing of the Mountain Pass ore. MP Materials has extensively piloted roasting and leaching variations from concentrate produced over different periods (early 2018, 2019, 2020, and 2021) and has always found the optimal results utilize similar conditions. Testing was conducted by 3^rd party laboratories, various vendors and cross-checked with legacy data, verified as consistent with Chinese processing conditions, and further piloted at bench, pilot, and commercial scale at MP Materials. These optimized conditions, apparently not coincidentally, were nearly identical to those practiced by its predecessor from 1966 to 1998.

This suggests that within the typical volatility of the ore body, these roasting and leaching conditions have produced the optimal results over time. In recent years, MP Materials has shipped approximately

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100,000 metric tonnes of REO to different processors in China. MP Materials understands that the vast majority of its customers pursue a similar hydrometallurgical process as is planned by MP Materials. Despite the concentrate being produced from different mining phases of the open pit (and different ore blends and final concentrate grades), the sales pricing framework has remained largely intact. This suggests that the leaching recovery has been consistent over the four-year period, providing further comfort of the representativeness of the samples tested.

Once the bastnaesite has been leached, it is not expected that variations in mineralogy will materially impact plant performance. Therefore, satisfaction of consistent leachability should provide sufficient support for the assumption of the suitability of the process design for life of mine.

10.4.3 Analytical Laboratories

MP Materials has been supported in its process design effort by a number of institutions and laboratories, as shown in Table 10-4. With the exception of MP Materials’ own analytical and engineering laboratories, all are fully independent of MP Materials and were compensated on a fee-per-service basis with no compensation tied to results achieved.

Table 10-4: Analytical Laboratories

Name	Location	Certification
Hazen Research, Inc.	Golden, Colorado, USA	https://www.hazenresearch.com/capabilities/analytical-laboratories
SGS Lakefield	Lakefield, Ontario, Canada	https://www.scc.ca/en/system/files/client-scopes/ASB_SOA_15254- Scope_v2_2021-07-30.pdf
Paterson & Cooke USA Ltd	Golden, Colorado, USA	http:///www.dcmsciencelab.com/certifications/ through DCM Science Laboratories
Golder Associates Inc.	Lakewood, Colorado, USA	https://acz.com/index.php/certifications/ through ACZ Laboratories Inc.

Source: MP Materials, 2021

10.4.4 Separations Facility Recovery Estimates

In order to design, size, and optimize the operation of the circuits in the Stage 2 process, MP Materials has analyzed legacy plant data and conducted (and continues to conduct) a range of bench-scale and larger-scale pilot activities. The primary end points relate to the following, summary data of which will be explained in more detail in the subsequent sections:

1) Optimizing roasting and leaching conditions to maximize trivalent (La, Pr, Nd, SEG+) rare earth recoveries while maintaining cerium recovery below 20%

2) Ensuring sufficient settling rate of cerium concentrate with clear thickener overflow

3) Efficient iron and uranium removal with minimal REE loss

4) pH adjustment and further impurity removal with minimal trivalent REE loss

5) Clean separation of Nd from Sm, with a focus on minimizing Sm into the raffinate stream (i.e., into Nd)

6) Clean separation of PrNd from La and Ce along with pure La and on-spec Ce (with no more than 20% La)

7) Sufficient settling of PrNd oxalate with clear overflow and low impurities

8) Sufficient settling and purity of lanthanum carbonate

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9) Ability to remove non sodium (Na) impurities from brine stream to feed the crystallizer, allowing for relatively pure sodium salt (non-Resource Conservation and Recovery Act) discharge that could be either sold or disposed onsite in the Northwest Tailings Disposal Facility (NWTDF)

The data confirms the recovery figures shown in Figure 10-4.

Overall Recovery: Concentrate to Finished Products
Lanthanum	78.5	%
Cerium	9.2	%
Praseodymium/Neodymium	89.6	%
SEG+	97.8	%

Source: MP Materials, 2021

Note: SEG+ includes the impact of LREE losses into SEG+ stream (considered an impurity)

Figure 10-4: Recovery Estimates

Summary of Continuous Roasting and Leaching

Experimental Conclusions 

For the leach pilot, an optimal extraction of 94.63% Nd₂O₃ and %Pr₆O₁₁ and %SEG+ was achieved at 109 grams per liter (g/L) REO in pregnant leach solution (PLS). Respective Ce extraction was 13.90%. During the stabilized run of the pilot, the highest achievable consistent g/L was 125 to 127 g/L. The respective optimal cerium extraction achieved was 9.57%.

Experiment Background and Objectives 

During previous runs of the REE separation circuit at Mountain Pass, further downstream processes were required to separate cerium from the blend of rare earth elements in the concentrate. The purpose of this pilot was to show that parametric optimization of the roasting and leaching conditions in the leach circuit can result in the rejection of 80%+ cerium oxide and the extraction of 90%+ PrNd and SEG+ Oxides.

Experiment Metrics 

Experiment results are presented in Figure 10-5 and Figure 10-6 and in Table 10-5 through Table 10-7.

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Source: MP Materials, 2021

Figure 10-5: Extraction of Rare Earth Oxides at 109 g/L with 93+% PrNd

Source: MP Materials, 2021

Note: Lower extraction of Nd2O3 and SEG+

Figure 10-6: Extraction of Rare Earth Oxides at 127 g/L

Table 10-5: Feed Conditions that Resulted in Optimal Extractions at 109 g/L

Ore Feed  Rate  (g/min)		RO Water (mL/min)		HCl TK2 (mL/min)		HCL TK3 (mL/min)		HCL TK4 (mL/min)		HCL TK5 (mL/min)		HCL TK6 (mL/min)		Total Volume Pilot Tanks (mL)		Residence Time Distribution (hours)
	8.3		18.3		1.8		1.4		1.4		1.4		1		17,500		9.55

Source: MP Materials, 2021

Note: “g/min” is grams per minute; “mL/min” is milliliters per minute.

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Table 10-6: Test Material Feed Composition by % Solid REO

La2O3%		CeO2%		Pr6O11%		Nd2O3%		SEG%+
	24.4		37.7		3.3		8.5		1.5

Source: MP Materials, 2021

Table 10-7: Outlet Stream Composition by g/L REO at 109 g/L

La2O3 g/L		CeO2 g/L		Pr6O11  g/L		Nd2O3  g/L		SEG g/L
	62.034		13.739		7.939		22.095		3.3139

Source: MP Materials, 2021

Summary of Leach Slurry Settling Tests

Experimental Conclusions

With the assistance of two vendors, MP Materials evaluated various anionic high molecular weight dry flocculants mixed at 0.20% and dosed into 500 mL samples of well mixed slurry. It was found that two worked best at a minimal dosage of 40 ppm for all 3 CCD thickeners. For CCD 1, this translated to 1,012 grams per metric tonne (g/t) dosages and for CCD 2 and 3 translated to approximately 909.1 g/t. See Table 10-8 below for full breakdown.

Experiment Background and Objectives 

Tests were performed on the CCD 1 thickener feed slurry with both vendors’ products. Two products of similar settling efficacy were found.

Experiment Metrics 

Experiment results are presented in Table 10-8. NTU (as a measure of clarity) refers to nephelometric turbidity unit.

Table 10-8: Settling Test Results Including Overflow Clarity with Various Flocculants and Dosages

CCD	Test  Product #		Dose  (PPM)		Minimum Dosage  (grams/metric tonne)		Size	Settle	Clarity  (NTU)
1		1		40		1,012.0	Small	Fast		28
1		2		40		1,012.0	Small	Med.		1000+
1		3		40		1,012.0	Small	Fast		428
1		4		40		1,012.0	Small	Med.		1000+
1		1		40		1,012.0	Small	Fast		23
1		5		40		1,012.0	Small	Fast		38
1		6		40		1,012.0	Small	Fast		113
1		1		40		1,012.0	Small	Fast		50
1		7		40		1,012.0	Small	Fast		36
1		2		40		1,012.0	Small	Med.		1000+
1		7		40		1,012.0	Small	Fast		29
1		1		40		1,012.0	Small	Med		29
2		1		40		909.1	Small	Fast		45
3		1		40		909.1	Small	Fast		31
1		8		40		1,012.0	Small	Fast		31
1		8		40		909.1	Small	Fast		31
1		8		40		909.1	Small	Fast		31

Source: MP Materials, 2021

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Summary Fe/U Loading and Losses

Experimental Conclusions

The range of Fe in MP Materials’ leach solution exists nominally within a range of 200 to 400 ppm, and, as such, ion exchange loading capacity is reported as a range respective to these two conditions. With the addition of 12N HCl and a 10% dilution of the feed solution, it is possible to reach a loading capacity of 0.95 to 1.89 L mother liquor/L column resin. With the addition of 1.8 N NaCl and a 10% dilution of the feed solution with 12N HCl (total Cl- of 3N), that number can be increased to 5.59 to 11.18 L mother liquor/L column resin. It was determined that 250 g/L of solid NaCl (4.27 Mol Cl-) can be safely added to further boost the loading capacity of the resin and that NaCl should be dissolved first to avoid the formation of sodium hydride salts in the reactor. At a 20% dilution with 12N HCl, this would increase the loading capacity to 22.18 to 44.36 L mother liquor/ L column resin. Mass balances of the rare earths that hover between 98% and 102% indicate analytical statistical error and are not indicative of rare earth losses to the resin. However, loading of iron and uranium can be observed as shown in the mass balance of cell 10 of Table 10-10.

Experimental and Objectives 

The objective of these experiments is to alter the Cl- composition of the feed stock leach liquor to improve loading capacity of the Fe/U IX columns. This is achieved with the addition of HCl and NaCl.

Experimental Metrics 

Experiment results are presented in Figure 10-7, Table 10-9, and Table 10-10.

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Source: MP Materials, 2021

Figure 10-7: Volumes of Leach Liquor per Volume of Resin Required Before a Regeneration Cycle

Table 10-9: Assays of Feed, Cell of Complete Rare Earth Breakthrough, and Cell of Fe/U Bleed

Sample ID	La2O3  g/L		CeO2 g/L		Pr6O11  g/L		Nd2O3  g/L		Fe mg/L		Na mg/L		U mg/L
INFLB Cell 10		36		22.14		5.69		21.91		2.7		34840.9		0.1
INFLB Cell 78		36.47		22.4		5.56		22.1		65.3		34257.3		5.3
INFLB Feed		36.89		22.53		5.54		22.55		129.7		34195.9		19.1

Source: MP Materials, 2021

Table 10-10: Mass Balance Calculations for Outlet Streams at Various Fractions

Sample ID	La/La Feed		Ce/Ce Feed		Pr/Pr Feed		Nd/Nd Feed		Fe/Fe Feed		Na/Na Feed		U/U Feed
INFLB Cell 10		97.59%		98.27%		102.71%		97.16%		2.08%		101.89%		0.52%
INFLB Cell 78		98.86%		99.42%		100.36%		98.00%		50.35%		100.18%		27.75%
INFLB Feed		100.00%		100.00%		100.00%		100.00%		100.00%		100.00%		100.00%

Source: MP Materials, 2021

Summary of Impurity Removal

The Impurity Removal circuit is designed to achieve a high purity SX feed. First the pH of the liquor is increased by the addition of 32% NaOH solution to the highest practical value with less than 1% of rare earth losses. This process was piloted at Mountain Pass in Summer 2021 to attain process parameters. A secondary goal of the pilot work was to determine whether this could serve as the primary aluminum-removal step for MP Materials’ entire plant process.

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Figure 10-8 shows a before and after for the steady-state operation of the pilot effort. The assay for “T2 Shift Avg” represents the product stream of this pilot work. The absolute concentrations are listed as well as the adjusted values.

Sample ID	La2O3 g/L	CeO2 g/L	Pr6011 g/L	Nd2O3 g/L	Sm2O3 g/L	Eu2O3 g/L	Gd2O3 g/L
Fe/U-removed leach liquor	27.065	30.054	4.386	19.510	3.953	0.247	0.163
T2 Shift Avg - Absolute	24.093	26.003	3.986	17.862	3.634	0.219	0.148
T2 Shift Avg - Dilution Adjusted	26.310	28.396	4.353	19.505	3.969	0.239	0.162
T2 % Loss	2.79	5.52	0.76	0.03	-0.39	3.01	0.95

Source: MP Materials, 2021

Figure 10-8: Mass Balance

The pilot effort also showed that an additional aluminum removal step will continue to be required.

Summary of SXI Recovery / Mass Balance

A subsequent impurity removal stage has two main functions in the overall MP Materials flowsheet:

• Remove the divalent impurities from the leach liquors

• Increase the concentration of rare earth elements feeding solvent extraction

One of the relevant modifications in the circuit from the legacy operations is that around 10% of the lanthanum present in the feed stream will be intentionally rejected. The process was tested on a pilot scale for a total of 10 weeks to achieve statistical process control.

Summary of SXH Recovery / Mass Balance

The SXH circuit which follows the solvent extraction impurities (SXI) circuit in the overall MP Materials flowsheet, receives the purified SX solution as the feed, after a stage of pH adjustment. The primary functions of the SXH circuit in the circuit are:

• To separate the heavy fraction (i.e., the SEG+ elements) from the light rare earths (i.e., LaCePrNd fraction). The light REE fraction is subsequently separated in the SXD circuit

• To concentrate the SEG+ fraction from ~20 g/L to ~350 g/L in the preg stream

The process has three input streams as shown below in Figure 10-9; Feed, NaOH, and HCl. There are two output streams: Raffinate containing the light REs, and the heavy RE-enriched preg stream.

Source: MP Materials, 2021

Figure 10-9: Diagram of the SXH Process

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The process was run on a pilot scale using a synthetic feed produced by blending SXI preg with heavy rare earth element (HREE) concentrate produced from the legacy circuit. Although the REO distribution in the synthetic feed does not match what would be encountered in the full-scale plant, the outcome of the testing would be the same at plant conditions. Piloting feed concentrations were adjusted to provide a reasonable timeframe for results.

The process control of the circuit was done by complexometric titrations to measure the REO concentrations in different streams of the circuit. Additionally periodic samples were analyzed by ICP-MS to evaluate the efficacy of the process. The concentrations of relevant species, i.e., Pr, Nd and Hv (abbreviation for SEG+ fraction), in the pilot during steady state are given in Table 10-11 with the flowrates.

Table 10-11: Volumetric Flowrates of Different Streams along with Mass Flowrates of Different Components

	Feed		NaOH		Scrub		Strip		Raffinate		Preg liquor
Flowrate (ml/min)		60		6.4		5.2		12.2		71.6		12.2
Pr g/L		0.77		0		0		0		0.828		0.008
Nd g/L		3.1		0		0		0		2.5		2.4
Hv g/L		33.2		0		0		0		0.068		342

Source: MP Materials, 2021

The elemental distribution of the raffinate, preg, and feed streams as shown in Figure 10-10, indicate that >99.5% of the light REE fraction reported to the raffinate and >95% of the heavy REE fraction reported to the preg solution in the pilot run described. This effort also resulted in 7.7% Nd losses in the pregnant solution stream. As the synthetic feed had significantly higher proportion of HREEs (65% by weight) in contrast to the natural distribution of REEs in bastnaesite (~2% by weight), the purity numbers achieved were not optimized. Furthermore, to minimize the heavy fraction in the raffinate, greater than optimal concentration of neodymium was lost in the pregnant liquor stream. The large separation factor between Nd and Sm and the legacy operation indicates that high yield and purity of Hv can be achieved with low loss of Nd into the pregnant solution.

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Source: MP Materials, 2021

Figure 10-10: % REO in Feed, Raffinate, and Preg Liquor

Summary of SXD Pilot 

Piloting data for SXD indicated that >99% pure (Pr/Nd)Cl₃ can be produced as a product in both the traditional configuration, and in a new configuration. The new configuration increased the purity of the La in raffinate to be >99.5% pure for sustained periods of several days, while maintaining the purity of the PrNdCl₃ product. The purity of the Ce-La product achieved was >99% with an average ratio of Ce to La of 2.87 (74% Ce) on an oxide basis. The low residence time of the mixer settlers as well as the low inventory volume led to high volatility compared to what is expected in the full-scale operation. In the full-scale operation, it is believed that even higher purity may be achieved due to increased SX circuit stability. Characterization of Ce and La in the PrNdCl₃ product was to the nearest 1 g/L.

PrNd Oxalate/Carbonate Precipitation – PrNd 

PrNd Precipitation was conducted with SXD Pregnant Solution (containing 166 g/L TREO at about 30% Pr and 70% Nd) and precipitant being fed into Reactor 1 and cascading down a series of four reactors before overflowing into a collection bucket.

Average recovery for the first five days was 99.9%, suggesting that even at feed ratios close to (or even slightly lower than) 1.0 can achieve nearly complete recovery.

From this study, stoichiometric feed ratio may be a good starting point for determining feed rates, but from a control standpoint, pH appears to be a good indicator for precipitation performance. Based on the data, low pH values should be targeted.

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Lanthanum Carbonate Precipitation – Summary of La Recovery 

Lanthanum Carbonate Precipitation was conducted with a solution containing 70 g/L of lanthanum on an oxide basis and soda ash solution (at 15% sodium carbonate by weight) being fed into Reactor 1 and cascading down a series of four reactors before overflowing into a collection bucket.

Figure 10-11 shows the stoichiometric feed ratio (actual/theoretical for soda ash) and residual TREO in the overflow liquor (both via ICP and manual titration) over the course of a two-week period. Stoichiometric feed ratio was calculated from recorded feed rates measured every two hours using a stopwatch and graduated cylinder. This crude method may account for some of the noise in this dataset. Average recovery for the first five days was 90.3%.

Source: MP Materials, 2021

Figure 10-11: TREO in Overflow Liquor Over Time vs Stoichiometric Feed Ratio and pH

On day six, soda ash flow became more erratic. In response, a reduction in lanthanum recovery is noted. While there were periods of time where flow was normal, this circumstance did not appear to be sufficient to maintain a consistent level of recovery in the pilot facility, suggesting that a consistent flow is critical to the operation of carbonate precipitation. This situation should be more easily maintained in the full-scale process.

Brine Recovery Summary

The Brine Recovery circuit is designed to remove impurities via carbonate precipitation from the brine crystallizer feed stream and allow for the impurities to be impounded as carbonate solids. This process was piloted at Mountain Pass in Spring 2021 to display proof of concept and to attain process parameters.

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The Mountain Pass pilot showed that impurities can be removed from the crystallizer stream to the point at which the wet cake salt (generated from the crystallizer) may be impounded. The Company would like to sell the salt as a product in the future. The pilot work also showed that the solids generated from the process are permissible to be impounded.

Table 10-12 shows the average concentrations of relevant impurities from the Mountain Pass pilot effort. The Impurity Removal Solution is an average of multiple grabs from the starting material, while the crystallizer feed is multiple grabs of the supernatant generated from the thickener.

Table 10-12: Impurities in Brine Before and After Treatment

Brine Recovery Pilot - Average of Grab Sample Assays
Component	Unit of Measure	Impurity Removal Solution		Crystallizer Feed
Al	mg/L		5.0		<0.1
Ba	mg/L		2,240		0.56
Ca	mg/L		23,845.1		2.4
Co	mg/L		3.0		<0.1
Fe	mg/L		6.0		<0.1
Mg	mg/L		345.4		<0.1
Mn	mg/L		249		<0.1
Na	mg/L		69,864		66,192
Ni	mg/L		1.3		<0.1
P	mg/L		5.3		0.4
Pb	mg/L		200		<0.1
Si	mg/L		18.8		1.2
Sr	mg/L		4,587		0.44
Th	mg/L		<0.1		<0.1
U	mg/L		<0.1		<0.1
Cl	mg/L		77,302		76,837
PO4	mg/L		13.4		2.1
SO4	mg/L		7.0		14.2
K	mg/L		78.0		54

Source: MP Materials, 2021

The thickener from the pilot plant did not provide any relevant data regarding settling time, however the solids did settle easily with both flocculants which were deployed.

10.4.5 Expected Product Specifications

Lanthanum Carbonate/Oxide

For lanthanum, MP Materials has designed its circuits to primarily meet the required specifications for the FCC catalyst market in the U.S. and Europe, which are the largest future customers. These specifications are not considered exceedingly tight, and the implementation of the SXD upgrades in MP Materials’ Stage 2 will enable the Company to alter the amount of lanthanum directed into the cerium chloride product to ensure on-spec La/TREO for those customers requiring higher purity La carbonate or oxide. MP Materials produced sample material for customer testing during the SXD pilot operation in mid-2020, which confirmed the ability to meet these primary specifications.

Cerium Chloride

The cerium (or cerium-lanthanum) chloride market does not yet have a fixed specification. However, the ratio of cerium to lanthanum, in MP Materials’ experience, does not dramatically impact performance. MP Materials’ predecessor produced and sold cerium chloride solution into the market for several years, and MP Materials has continued to sell legacy inventory of this product to an existing

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customer at premiums to observed market prices. The MP Materials flowsheet will produce cerium chloride in a similar process flow to the predecessor, where there should be no difficulty continuing to meet market expectations. Product that does not meet market specifications can be recycled back to the separation plant or neutralized and disposed through brine recovery without significant financial impact.

PrNd Oxide

Market standard PrNd oxide specifications, as confirmed by MP Materials’ customer discussions, are demonstrated in Figure 10-12. Mountain Pass’s primary production and separation assets were previously operated at commercial scale, and several representative 5 metric tonne lots are compared to market specifications below, highlighting the ability to produce on-spec PrNd Oxide. Further, MP Materials will be implementing more robust solid liquid separation, QA/QC, and finishing assets, which are expected to improve upon the ability and economics of producing to market specification.

Source: MP Materials, 2021

Figure 10-12: Market Standard PrNd Oxide Specification and Mountain Pass Historical Results

SEG+ Oxalate

There are varying specifications for SEG+ Oxalate products driven by the varying ratios of Tb and Dy and purity requirements. The typical SEG+ contract would include a minimum Tb and Dy assay percentage.

A representative SEG+ transaction specifies a 4% Tb+Dy minimum (REO equivalent). While there is sample volatility due to low concentrations of certain elements, recently produced samples from material extracted from legacy circuits and other testing indicate between 4% and 8% as a conservative range for Tb+Dy.

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11 Mineral Resource Estimate

The mineral resource estimate was prepared and reported by SRK Consulting (U.S.) Inc.

Mountain Pass site geology is modeled using Seequent’s Leapfrog Geo^™ software, and a 3D block model, grade estimation, and classification are developed in the same software utilizing the EDGE module. Pit optimization was conducted in Maptek Vulcan^™ software. The Project limits are based on the near-mine area and are represented in local mine coordinate system.

Rare earth mineralization at Mountain Pass is contained within intrusive carbonatite hosted by Proterozoic gneissic and shonkinitic/syenitic rocks. Rare earth mineralization has a relatively constant dip of 35° to 45° to the west southwest (255^o), offset by minor post-mineral west and north-northwest normal faults. Drillholes are predominantly vertical to steeply dipping almost perpendicular to the dip of the mineralized zone. Drill spacing averages 100 to 300 ft throughout the deposit along the strike and downdip. Most of the drilling occurred prior to or during mine production in the early 1950’s to late 1990’s. The current mineral resource estimate incorporates drilling and mapping information that has been sourced or revised by MP Materials as part of a geological database review process in 2021.

SRK generated the mineral resource estimate in 2021 based on drillhole sample assay results. The estimate is constrained by a combination of lithology and TREO grade shell domains. Grade interpolation was defined based on the geology, drillhole spacing, and geostatistical analysis. The mineral resources are classified based on geological understanding, historical production, proximity to drilling data, number of drillholes used in the estimate, and relative indicator of estimation quality (Kriging Efficiency (KE)). The reported mineral resources are reported above a nominal cut-off grade (COG) developed from assumptions of internal cost and pricing from MP Materials, and within an economic pit shell to demonstrate reasonable prospects for economic extraction.

11.1 Topography and Coordinate System

The mineral resource estimate has been confined to a topography dated September 30, 2023. The Mountain Pass property utilizes a local mine in easting and northing with elevation being true elevation above mean sea level (amsl). The local mine grid is based in U.S. feet (ft).

11.2 Drillhole Database

As described in Section 7, the majority of drilling activities at the Project were conducted throughout the 1950’s to 1990’s, and data was recorded in U.S. standard units with locations in a local mine grid. Drilling locations relevant to the project area are shown in Figure 11-1.

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Source: SRK, 2021

Figure 11-1: Drilling Distribution near Mountain Pass Mine

MP Materials compiled a digital drilling database based on information available from original laboratory analyses. In some cases, the original lab sheets were not located, and SRK relied on typed and hand-written analyses as posted on drilling logs. This database differs from previous drilling information compiled by SRK or other consultants and includes revisions to historical information based on relatively newly discovered records as well as drilling added to the database from 2011 to 2021 drilling. MP Materials compiled this drilling database in Microsoft Excel.

The drilling database used for the current resource model utilizes a total of 233 drillholes with a cumulative length of 118,621 ft in the vicinity of the mine area. SRK notes that there are additional drillholes in the database excluded from the resource estimate as they were completed for other purposes (hydrogeological, geotechnical, etc.), could not be located accurately from historical information, or were outside of the project area. Individual drill holes range in length from 50 to 2,499 ft, and average 510 ft. The drilling is located on a series of generally east-northeast and east to west oriented sections spaced at nominal 150 ft intervals. Drill spacing is not consistent down-dip and less than 100 ft in the higher-grade center of the deposit but widens to over 300 ft in other areas. Drillhole spacing averages approximately 200 ft x 100 ft throughout the deposit area.. In some cases, there are drill holes that contain geological logging, but missing assay data. These holes are outside of the main carbonatite zone but are used to inform the geological model.

Within the geological model, there are 6,975 samples analyzed for TREO with grades ranging from 0.01% TREO to a maximum of 26.42% TREO. Historically, core samples were selectively assayed based on visual confirmation of mineralization. Accordingly, many intervals in the hangingwall and footwall of the mineralized zone were not assayed and thus, assigned a -0.01 TREO grade. These intervals were re-assigned a grade of 0.001 % TREO by SRK for the purposes of domain evaluation and estimation. Intervals which are entirely missing in terms of logging and assays are rare within the mine area and were omitted from compositing and estimation.

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Individual sampling intervals range from 0.9 ft to a maximum of 21.5 ft, with an average of 5.14 ft. On a percentage basis, more than 83% of the sample internal in the carbonatite are 5 ft with another 7% between 5 and 10 ft (Figure 11-2). A portion of the samples have also been tested for multi-element geochemistry including P₂O₅, CaO, SrO, Fe₂O₃, PbO, SiO₂, ThO, with a limited selection of lanthanide series elements assayed. Only P₂O₅ was evaluated and estimated in the model to potentially aid in determination of where monazite may host the rare earth content, but this is not reported in the mineral resource summary and is not utilized for reporting.

Source: SRK, 2021

Figure 11-2: Sample Length Histogram – Mineralized CBT

There is limited information available regarding drilling recoveries recorded on the original drill logs. Anecdotal information by site personnel indicates acceptable core recovery, and no relationship was historically observed between core recovery and TREO grade. Zones of low or no recovery are noted in drilling logs and generally remain unsampled due to lost core. These intervals neither contribute to, nor are assigned grade on the basis of review of the drill logs and communication with site personnel. If there was an issue with recoveries, SRK would expect this to be evident as the relationship between recovery and grade as a result of the highest-grade ore being also very friable; this should be reviewed in more detail in future.

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11.3 Geology

SRK modeled the geology in 2021 as 3D wireframes utilizing Leapfrog Geo^™. Downhole geological information has been compiled from physical paper records for most of the historical drilling at Mountain Pass. In addition to the drilling, SRK registered geological mapping to the corresponding topographical surfaces and incorporated this mapping into the modeling effort as GIS or polylines in Leapfrog. Most important to this effort was the mapping completed by MP during July and August of 2021 to inform areas where historical exploration drilling was relatively sparse in the pit area. This is shown in Figure 11-3.

Source: SRK, 2021

Figure 11-3: Geological Mapping and Fault Expressions – August 2021

11.3.1 Structural Model

SRK constructed a structural model including the five major faults observed in the open pit. SRK utilized the structural mapping from the July-August 2021 pit mapping as primary contacts for structures observed in the pit area. These include:

• Celebration Fault – Offsetting carbonatite (CBT) and trending NW along orientation of CBT.

• Middle Fault Zone – Identified as a relatively wide damage zone dipping to the W from the pit area.

• QAL Fault – Significant down-dropping W-NW fault exposed in south pit wall. Juxtaposes QAL with host rocks and would offset CBT. No drilling has identified CBT south of this fault.

• F1 Fault – Mapped as minor down-dropping fault trending W-NW. Likely sympathetic to Quaternary alluvium (QAL) Fault Offsets and truncates CBT to the south.

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• F2 Fault – Appears to be NE trending minor splay of Middle Fault Zone. Not activated in the geological model due to minimal or no perceived offset but retained to inform geotechnical model development.

• Shear Zone - Appears to be NW trending shear developed in central part of pit. Not activated in geological model due to minimal or no perceived offset but retained to inform geotechnical model development.

Where possible, SRK projected these structures from pit measurements and linked them to intersections of structure noted in the drilling, when available. The structural logging is inconsistent in the drilling. It is likely that observations were not recorded which may correspond to other structures or that some observations should be ignored due to the same inconsistency. Relative interactions of the structures noted above were reviewed with MP geology staff for consistency to the observed mapping and current geological interpretation. The resulting interactions effectively define fault blocks which are discrete from each other and bound the lithological model.

11.3.2 Lithology Model

The lithology was modeled based on drill logging simplified to key units at a level commensurate with the relative consistency of the drilling and mapping information. Basic lithologies which could be grouped from the variable historical logging were carbonatite (CBT), host rock (HOST - primarily gneiss with minor granite/shonkinite/syenite), and Quaternary alluvium (QAL). Although sub-lithologies are defined, the inconsistency of the logging over various generations would result in inaccuracies and potential errors in the model. In addition, the relative importance of the definition of sub-lithologies is considered minor according to the current operational mine plan. The primary purpose of the geological model at Mountain Pass is to define areas with different densities and waste rock geochemistry, slope stability, or other general engineering parameters. Thus, a more detailed lithological model was not deemed necessary by MP to support mineral resources:

• The QAL was defined as an erosional surface superseding all other lithologies as the most recent unit and is informed primarily from drilling. Surface mapping of the distribution of the QAL is incorporated from 2013 geological mapping of the area.

• Carbonatite was modeled primarily from the grouped logging codes which represent carbonatite logging information generated over the various drilling campaigns. SRK notes that TREO grade was not utilized to generate the carbonatite shape, and that this was based purely on the geological logging or mapping conducted by MP or predecessors.

• Host or country rocks are effectively the remaining volume not broken out for CBT or QAL. The host rocks are mixed and generally understood to not vary significantly in terms of bulk density or other parameters relevant for the current operation.

• A fault damage zone was also constructed between the hangingwall and footwall surfaces of the Middle fault zone and is a separate lithology for the purposes of evaluating specific gravity, rock mechanics, hydrogeology, or other relevant disciplines.

A rotated view of the 3D geological model is shown below in Figure 11-4.

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Source: SRK, 2021

Note: Faults shown as shaded linear features.

Figure 11-4: Plan View of 3D Geological Model

11.3.3 Mineralogical / Alteration Model

No mineralogical or alteration model has been developed for the Project. In general, consistency in nomenclature of specific types of carbonatite or alteration in the carbonatites or host rocks has been poor. MP has previously noted carbonatite “types” that may exist internal to the CBT orebody, primarily based on ore type designations including “black” (high grade relatively friable CBT), “blue” (low grade CBT featuring chrysotile), and “breccia” (marginal or contact-altered CBT which is more friable and erratic in terms of REO distribution). The data is inconsistent in its approach to defining these zones in the drilling or mapping, and SRK elected to not model these features. Anecdotal discussions with MP personnel noted that these types of carbonatite which may be observed are generally dealt with satisfactorily through the current blending strategy, and generally have no impact on overall metallurgical recovery or other economic/operational factors.

SRK notes that ore typing within the CBT is currently done solely on the basis of TREO grade, and that mineralogy or alteration are not considered in mine scheduling, mill feed, or downstream economics. If this changes over time, significant effort will need to be applied to either re-logging

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historical drilling on a consistent basis for these details or utilizing other means to obtain and characterize this data.

11.4 Exploratory Data Analysis

11.4.1 Resource Domains

The modeled CBT volume has been domained into high-grade (HG) and Undifferentiated (UNDIFF) domains. Based on exploratory data analyses (EDA), SRK’s opinion is that, sub-domaining of the CBT is appropriate based on likely mineralization multiple phases or types of intrusion within the broader CBT volume. . Unfortunately, the inconsistency of the geological data does not provide a robust mineralogical or other categorical feature appropriate for producing a model of the phases internal to the CBT. SRK notes there are a number of published papers that have discussed the variable mineralogy and its relationship to REO grades, but reasonable spatial models of these features have not been generated to date.

A histogram of the REO grades internal to the CBT unit is shown in Figure 11-5.

Source: SRK, 2021

Figure 11-5: Histogram of TREO% within CBT

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The bimodal nature of this histogram distribution and a review of the spatial context of these populations shows a distinctly higher-grade interior portion of the CBT relative to a more erratic and undifferentiated lower grade outer zone of the CBT. This is consistent with in-pit observations of the CBT, as well as the local sectional interpretation of the CBT. SRK selected a nominal 5.0% REO cut-off for the purposes of generating an indicator model of the higher-grade portion of the CBT. In addition to the threshold of 5.0% REO, a probabilistic factor of 0.4 was used to assess intervals and areas for which the probability of exceeding the 5.0% REO cut-off was greater than 40%.

Other parameters defining this domain are as follows:

• The same structural trends utilized for creation of the CBT unit itself were applied to the indicator.

• The indicator was limited to samples only within the CBT, and each fault block defined from the structural model constrained its own indicator.

• Continuity was applied to the indicator for interpolation in Leapfrog. The range was set to 300 ft, with a total sill of 0.2 and a nugget of 0.02 (10%). No drift was applied.

• Discrete volumes less than 10,000,000 ft³ were discarded.

The results of the TREO grade-based domaining process provided a robust constraint on grade distribution within the CBT which define a relatively contiguous “core” of REO mineralization relative to the undifferentiated CBT. Performance statistics for the indicator also show robust dilution metrics of approximately 7.2% of samples within the domain being lower than the defined COG. It is SRK’s opinion that this domain is acceptable for use in mineral resource estimation, and a reasonable approximation of the geological features and related grade distribution of the deposit (Figure 11-6).

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Source: SRK, 2021

Note: Looking SE

Figure 11-6: Cross-Section Illustrating CBT Domains and TREO Grades

11.4.2 Outliers

SRK performed an outlier analysis aimed at identifying high-grade outlier values that may adversely impact grade estimation. It was determined that no capping was necessary for TREO but outlier influence restriction was utilized. Upper-end log probability plots for TREO within the two domains are provided in Figure 11-7 and Figure 11-8, respectively. Other capping scenarios were evaluated for each data population and demonstrated relatively low sensitivity to a capping strategy in terms of impact to average grade or coefficient of variation (CV).

SRK elected to utilize a reduction of influence or a “clamp” for reducing the impact of outliers on the grade estimation. For this, SRK assumed that the full composite grade would be utilized for a relative distance of 30 ft (one block) after which the grade would be reduced to a nominal upper limit level as defined below in Table 11-1. This outlier restriction is applied during the estimation, and successfully retains the local high grade as have been demonstrated to exist but reduces the scope of their impact

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on larger volumes and distances which are not likely as supported based on the probability plots. SRK generated probability plots for the two domains and visually reviewed the consistency of populations at varying grade ranges to understand both the spatial context of the outlier populations (i.e., what part of the orebody contain outliers) as well as the consistency of the populations to each other.

Table 11-1: TREO Influence Limitations

Domain	Outlier Threshold Level (%)	Distance (ft)	Percentile of Distribution
HG Core	18.0	30	98.88
Undifferentiated	10.5	30	99.50

Source: SRK, 2021

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Log probability plot REO4_2021 cap=18 capped=21 CV=0.43 Total Lost=0.3%

Source: SRK, 2021

Figure 11-7: Log Probability Plot for TREO – HG Core

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Log probability plot REO4_2021 cap=10.5 capped=14 CV=0.9 Total Lost=0.3%

Source: SRK, 2021

Figure 11-8: Log Probability Plot for TREO – Undifferentiated CBT

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11.4.3 Compositing

All exploration assay data were composited into 10 ft downhole lengths. Composites were broken by the CBT and internal resource domains for use in grade estimation.

Blastholes were composited to their nominal 30 ft bench height, or 15 ft in selected older holes which were not drilled to the full bench height.

11.5 Bulk Density

For the purposes of determining the bulk density at the Mountain Pass deposit, SRK reviewed historical tonnage factors and collected limited samples for specific gravity testing. For the purposes of calculating tonnages in the resource model, bulk density is considered the same as specific gravity.

For all historic resource and reserve estimates, a tonnage factor of 10.0 ft³/ton (specific gravity = 3.20) was applied to mineralized carbonatite, and a tonnage factor of 11.5 or 11.0 ft³/ton (SG = 2.79 to 2.91) was applied to the enclosing country rock (Cole, 1974; Couzens, 1997, Nason, 1991). Original documentation related to specific gravity cannot be located, although it was reported that IMC performed a truck weight study in the field on waste rock during prior operations.

In order to validate the historical specific gravity assumptions, SRK collected a total of 10 samples for specific gravity determination, and the results of this testwork are provided in Table 11-2. Based on these results, SRK assigned a tonnage factor of 10.25 ft³/ton (specific gravity = 3.13) for mineralized carbonatite, and 11.57 ft³/ton (specific gravity = 2.77) for the enclosing gneissic rocks, which is in reasonable agreement with historical assumptions.

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 Table 11-2: 2009 Specific Gravity Results - Carbonatite

Sample ID	Hole		Sample Depth (ft)		g/cm3			ft3/ton		Rock Type	Notes
SGMP833531		83-3		531		3.22			9.95	Carbonatite	With red and brown flow foliation
SG854224		85-4		224		3.14			10.20	Carbonatite breccia	Pink and white to pink and brown matrix with green amphibole clasts altered to chlorite and sericite
SG859233		85-9		233		2.82			11.36	Gneiss	Fine grained biotite-qtz gneiss “sparse red feldspar and crocidolite mostly along veins”
SG8520427		85-20		427		2.62			12.23	Carbonatite	Dark yellow brown strong limonite replacement of carbonatite bastnaesite rare
SG8521437		85-21		437		2.72			11.78	Carbonatite breccia	With abundant syenite/shonkinite clasts
SG882399		88-2		399		3.29			9.74	Carbonatite breccia	Blue to red brown matrix pink to brown barite, abundant crocidolite
SG9013464		90-13		464		3.37			9.51	Carbonatite	Pink barite and white to gray calcite
SG9016244		90-16		244		2.87			11.16	Carbonatite	Pink barite and white calcite, iron pseudomorphs black ore up to 60%, some violet barite
SG9111153		91-11		153		2.91			11.01	Carbonatite breccia	Matrix supported breccia, matrix is light gray to maroon with salt and pepper texture, abundant feox
SG9111258		91-11		258		3.65			8.78	Carbonatite	Pink to light gray mottled with clear to light pink barite phenocrysts

Source: SRK, 2012

11.6 Spatial Continuity Analysis

Variography was calculated to model the spatial continuity of TREO grades within the relevant domains (and data types) for the Mountain Pass deposit. Orientations of the variograms were selected based on the overall geological continuity and generally follow a dip of 38° to an azimuth of 250°, with a varying pitch depending on the domain. Orientations of the orebody are known to vary locally, and SRK used broad orientation for directional variogram models given the expected use of variable orientations in the estimation process. SRK modeled both semi-variograms and normal-score transformed semi-variograms to achieve improved models for ordinary kriging interpolation. Back transforms for the normal score variography were done prior to estimation. Continuity ranges are between 400 to 500 ft depending on the data set. Blastholes generally demonstrate relatively shorter

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ranges compared to the exploration composites which is a function of both the closer spacing of the blastholes and the inherent variability of the blastholes relative to the more broadly continuous exploration data. Blastholes demonstrate comparably better short-range continuity due to this close spacing. In general, both sets of variograms (Figure 11-9 and Figure 11-10) show relatively steep rises to the sill, reaching 60-70% within 100-150ft, with the remaining variability coming over an additional 200-300ft. Nugget effects were modeled independently using downhole variograms for each domain and data set, and generally range from about 5% to 20% of the sill.

Source: SRK, 2021

Figure 11-9: Example of Directional Variogram – Blastholes TREO

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Source: SRK, 2021

Figure 11-10: Example of Directional Variogram – Exploration TREO

11.7 Block Model Limits

A sub-blocked model was created in Leapfrog EDGE with the origin and extent presented in Table 11-3. The model features a total of 6,818,200 blocks and duplicates the geological volumes to within 0.2% of the wireframes in the model. Sub-blocking triggers in the 2021 block model include, topography, the 2013 topography bounding the geological model, the geological wireframes, and the resource domain boundaries. Blocks are coded with geological model codes, domain codes, densities, estimated TREO grades, and relevant supporting parameters derived from the estimation or classification process. All estimates were done at the parent block dimension, which is approximately 1/3 to 1/5 of the exploration drill spacing the majority of the deposit.

Table 11-3: Block Model Specifications

Axis	Minimum (ft)		Maximum (ft)		Number of Parent Blocks		Parent/Child Block Size (ft)
X		2,200		7,840		188		30/7.5
Y		7,800		13,200		180		30/7.5
Z		2,510		5,300		93		30/7.5

Source: SRK, 2021

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11.8 Grade Estimation

SRK estimated TREO from the composited assay values from both the exploration and blasthole data provided by MP Materials. Estimates were compiled into a single TREO variable for reporting with priority assigned to estimates using Ordinary Kriging (OK) from exploration data over inverse distance weighting squared (IDW2) estimation. A general description of the estimation process is below.

SRK first conducted boundary analysis of the high-grade core and undifferentiated CBT domains and noted that (particularly for blastholes) the domains appeared to be transitional over a relatively short distance (Figure 11-11). SRK elected to apply a soft boundary to the estimation process, by which each domain could use samples from within a 10ft buffer internal to the other, but not from outside of both.

Source: SRK, 2021

Figure 11-11: Domain Boundary Analysis – HG Core Domain within CBT

OK was used as the interpolation method. Orientations for search ellipsoids were varied as a function of the geology of the deposit as reflected from digitized surfaces representing the hangingwall and footwall of the carbonatite (Figure 11-12). This is commonly referred to as variable orientation modeling, and adjusts both the search orientation as a function of the relationship to the geological controls on mineralization. This was utilized for both the blasthole and exploration estimations.

The normal scores back-transformed variograms were used to inform the ordinary kriging estimate. Nested search neighborhood passes were used for exploration data estimates and were also utilized

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to assist in classification of mineral resources. Differences between the estimation relying on blastholes vs. exploration data is noted below.

Source: SRK, 2021

Figure 11-12: Variable Orientation Surfaces for Estimation Orientation

11.8.1 Blasthole Estimate Specifics

In general, SRK utilized a single 60 ft x 60 ft x 30 ft search pass from a minimum of three and maximum of 15 blasthole composites. Quadrant restrictions were applied to ensure that no estimates were unduly extrapolated beyond the tightly clustered blasthole data. This selection is not relevant to the blasthole variograms as the intent to only allow the blastholes to affect a maximum of two benches from the last data. This decision was made based on review of the inherent variability of the blasthole dataset relative to the exploration data and the naturally clustered data.

No outlier restrictions (limitations on influence) were placed on the blasthole data, as this data has been supported by production and affects a relatively small volume of blocks.

11.8.2 Exploration Estimate Specifics

SRK estimated grades from composite data using the 10 ft composites, within the relevant geological wireframes. Two nested search neighborhood passes were used, with the first pass was designed to estimate blocks within well-informed volumes. The first pass uses between 3 and 15 samples for estimation, with quadrant restrictions which must fill at least two quadrants, and only allow a maximum of two samples per hole to contribute to the estimate.

The second pass neighborhood was designed to populate unestimated blocks from the first pass by selecting relatively fewer data at larger distances. Second pass searches are 3X multipliers of the first pass (900 ft x 900 ft x 100 ft) and allow sample selection from as little as a single hole.

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Outlier limitations or clamping were used on interpolation in the exploration data. The first pass uses a nominal restriction of a value of 18% TREO or 10.5% TREO for the HG Core and Undifferentiated domains respectively, both to a distance of 10% of the search (30 ft = 1 bench) after which the original composite grade reverts to either of the values noted above. Similar restrictions were placed on the second pass in terms of grades, but reduces the distance applied to 3.33% of the total search (30 ft = 1 bench).

11.9 Model Validation

SRK performed model validation using several methods. These include a thorough visual review of the model grades in relation to the underlying drillhole composite grades in section and plan, comparisons with other estimation methods (inverse distance weighting and nearest neighbor), and statistical comparisons between block and composite grades and volumes. SRK has also reconciled the mineral resource model with production records as described in Section 11.10.

Visual comparison between the block grades and the underlying composite grades in plan and section views show close agreement, which would be expected considering the estimation methodology employed. An example cross section showing block grades, composite grades and resource pit outline are provided in Figure 11-13. Swath plots show excellent agreement between mean composites and block estimates over the various orientations, and generally demonstrate that estimates are respecting overall trends in grade with minimal smoothing as expected for a block estimate compared to composite drill data (Figure 11-14).

Source: SRK, 2021

Figure 11-13: NW-SE Cross-Section Showing Block Grades, Composite Grades, Resource Pit Outline

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Source: SRK, 2021

Note: Composite grades shown in red, ordinary kriged estimated grades shown in green, inverse distance estimated grades shown in blue, and nearest neighbor estimated grades shown in orange. Green bars illustrate relative volumes of blocks where the estimates are made.

Figure 11-14: Swath Plot (NS Orientation) Comparison Between TREO Block Grades and Composite Grades

11.10 Production Reconciliation

During 2020-2021, SRK has performed model reconciliation of the resource block model used for the mineral resource statement, which is based on exploration drilling only, against a grade control model, which is based on blasthole data collected by MP Minerals during routine mining operations. The follow section summarizes work completed for this reconciliation exercise as this work continue to support the confidence and classification of mineral resources at Mountain Pass.

The blasthole samples are 15 ft bench composite grades taken on a regular pattern with a spacing of approximately 12 ft. These grades were estimated into the same block model framework using a simple inverse distance weighting (IDW) method. SRK then analyzed the resultant grade distributions spatially and statistically. Figure 11-15 shows the grade distribution on two example benches.

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Source: SRK, 2012

Figure 11-15: Spatial Comparison of MRE Grade Distribution with Blasthole Grade Distribution

A regression plot showing resource model grade and blasthole model grade is shown in Figure 11-16. A best fit line through the cloud of points shows that on average, in higher grade parts of the deposit, blasthole model values are higher grade than resource model values. For example, where blasthole grades are around 14%, resource model grades are around 12%.

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Source: SRK, 2020

Figure 11-16: Comparison of Resource and Grade Control Models

In addition to the block model comparison exercise, a reconciliation was undertaken of material movements and tonnage and grade records based on production records from January 2020 to May 2020 (inclusive).

Based on the block model comparison described above, there is understood to be some 20% more TREO contained in the grade control model compared with the resource model when a 5% TREO COG is applied.

The production tonnage (mined ex pit) records are based on truck weightometer readings. Based on diglines in the pit which subdivided each bench into mining shapes depending on blasthole grades, each truck was known to be carrying material belonging to one of the following grade categories:

• >9% TREO

• 7% to 9% TREO

• 5% to 7% TREO

• 2% to 5%TREO

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The tonnages so recorded include planned and unplanned mining dilution.

The grades assigned to each category are those reported in the mine’s production records which come from the mine’s ore control (OC) model. Grades are based on blasthole data within practical mining dig lines representing each grade band, therefore incorporating planned dilution.

The trucked tonnage is locally 25% greater than that reported by the blasthole block model in the same January to May 2020 mining volume, largely as a result of planned and unplanned dilution. The trucked grade is some 20% lower due to the dilution, and the contained TREO is some 10% higher.

If these two steps are combined, the trucked tonnage is some 25% greater than the SRK model, and the grade is slightly higher (being 9.0% instead of 8.4%), resulting in some 35% more TREO being trucked than predicted by the SRK model. MP has noted that trucked tonnages include moisture content and that this may affect the accuracy of the reconciliation.

The direct crusher feed is blended with supplemental material sourced from stockpiles to achieve a planned mill feed grade. The planned mill feed tonnage and grade typically agrees well with the actuals according to weightometer records and mill samples. Therefore, the trucked tonnage and grade estimate combined with the estimated stockpile loadings and depletions can be considered robust. Despite the absence of routine QA/QC for the majority of resource drilling samples, SRK’s reconciliation study demonstrates that the MRE model is sufficiently reliable and demonstrably conservative for long-term mine planning and mineral resource and mineral reserve reporting.

11.10.1 Blasthole “Bias”

Subsequent to the reconciliation noted above, SRK compared the 2019-2021 production blasthole data against the exploration datasets by estimating both data into the same volume of blocks using similar methods and reviewing the spatial context of the discrepancies in reference to observations in the pit. Figure 11-17 shows the three general areas where this comparison could be made, i.e., where both data types exist at spacings within an approximate 60 ft x 60 ft grid. Table 11-4 shows a global comparison of each estimate within the same volume and supports the assertions from reconciliation to production that the blastholes are seen to predict higher grades than the exploration data. On review of this data spatially, SRK notes that much of this bias is observed in selected areas which are characterized by relatively little exploration drilling.

Because operational mining is informed by the blasthole data more so than the resource model, benches are taken relative to the blastholes over the exploration data by default. Since mining also tends to favor focus on higher grade material over waste, the bias trends positive in conventional reconciliation. A percent difference calculation of the two check estimates supporting this review is noted below in Figure 11-18, and shows these areas where the blastholes appear to have a high bias in red, vs. the opposite in blue. The blue areas, by comparison, are shown to be comparably lower in the blastholes relative to the exploration data, and the reconciliation process has simply been biased by the effects of mining higher grades over the relevant production period. Overall, SRK believes this indicates that the exploration data may not be able to predict the local variability of grade (implying the necessity of a local grade control/short term drilling program), but that this has not seemed to currently be an issue for the mine production. This is a contributing factor in Mountain Pass not being assigned a Measured level of confidence in the in situ mineral resource estimation and is discussed in classification.

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Source: SRK, 2021

Figure 11-17: Previous Production Areas for Reconciliation Validation

Table 11-4: Blasthole vs. Exploration Comparison

Resource Domains	Mass (thousand sh. Ton)		Average Value (%)				Material Content (Mlb)
			REO Blastholes		REO Exploration		REO BH		REO EXP
CBT - HG CORE		3,513		8.89		7.91		624		556
CBT – LOW GRADE		2,001		4.84		2.88		194		115
Total		5,514		7.42		6.08		818		671

Source: SRK, 2021

Note: Differences may occur in totals due to rounding.

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Source: SRK, 2021

Note: Warmer coloring indicates apparent high bias in blastholes vs. exploration, with cooler colors being the opposite.

Figure 11-18: Percent Difference BH/EXP Estimate

SRK considers there to be a few possible explanations for these outcomes:

• The most recent blastholes are processed using industry standard methodology in terms of material preparation or analytical bias. Moreover, MP Materials has noted in personal communication that blastholes generally agree with samples taken from the plant and stockpiles for production blending. Historically, the Mountain Pass Laboratory tended to underestimate higher grade sample assay values; there is no direct evidence of this, and no adjustment has been made to the historical assays.

• Exploration drill core used for the resource model may not recover high-grade friable ore as well as blastholes do; there is no direct evidence of this, and no adjustments have been made to account for this.

• The wider sample spacing in the exploration drilling is insufficient to characterize the inherent local variability of the orebody. SRK notes that this is likely the case based on observations in mining of the most recent production areas which feature local discrepancies between what is predicted by exploration drilling and what is in the pit.

o For the previous two years of production, this has been a positive swing with reconciled mine grade exceeding that predicted by the resource model. SRK notes that there is no guarantee that positive reconciliation will continue as a trend, and that the exploration drilling should be considered appropriate for long term resource estimation and not for short term production models. Additional tighter-spaced grade control drilling should support short and medium range planning for the operation to optimize local understanding of TREO distribution.

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11.11 Uncertainty and Resource Classification

All mineral resource estimates carry an inherent risk and uncertainty depending on a variety of factors, many of which influence or compound the effects of others. Mountain Pass is an operating mine, which implies that a certain amount of inherent risk in mineral resource estimation has been borne in the sunk cost of the operation and ongoing production to date. This being noted, uncertainty in the data collection and geological complexity of the deposit remain relevant to the estimation of mineral resources at Mountain pass. The primary mechanism utilized to minimize uncertainty for Mountain Pass has been to improve the geological modeling and utilize a more robust database and geological information repository than what has been used prior to recent modeling. This includes robust geological logging (previously not included in a database for modeling) and geological mapping from the pit. This has resulted in a complete structural and lithological model which SRK notes shows material differences from previous grade-based interpretations. Most importantly, SRK believes the current resource model to be satisfactory to support the resource classification performed and disclosure of mineral resources on the property.

SRK notes the following sources of uncertainty in the Mountain Pass resource model:

• The analytical QA/QC program at Mountain Pass is not considered consistent good industry practices. The limited historical QA/QC information that does exist shows relatively acceptable performance, but ongoing improvements are recommended by SRK.

• The exploration drilling has been sufficient to characterize a mineral resource at the classification applied and described in this report. SRK notes that the exploration drilling is considered at insufficient spacing to report a Measured reason based on the variability observed in the tighter spaced blasthole data.

o SRK notes that production reconciliation tends to show an underestimation of TREO grades. No studies have been conducted in terms of sample representativity or other potential biases between drilling methods. SRK notes that this apparent bias seems to be local and geological in nature, and simply is showing that higher grade areas of the deposit were “missed” by exploration drilling which have now been picked up by blastholes.

SRK has dealt with uncertainty and risk at Mountain Pass by classifying the contained resource by varying degrees of confidence in the estimate. The mineral resources at the Mountain Pass deposit have been classified in accordance with the S-K 1300 regulations. The classification parameters are defined by geological understanding of the deposit, confidence in drilling locations, quality of QA/QC, distance to composite data, the number of drillholes used to inform block grades and a geostatistical indicator of relative estimation quality (kriging efficiency). The classification parameters are intended to encompass zones of reasonably continuous mineralization. The distances utilized for resource classification are generally based on interpretation of the ranges based on the directional variography (Section 11.6).

Classification is assigned using an iterative process which followed a simple script to categorize blocks based on the parameters below and modified as necessary by the QP:

• Measured mineral resources: Tonnages of stockpiles at surface for mill feed. Stockpiles resources, as of September 2023, are based on detailed grade control, well-established bulk density and

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accurate survey data, and have been depleted according to a detailed short term mine plan and blending schedule.

o No Measured resources have been assigned to in situ resources at Mountain Pass at this time. This is based on relatively inconsistent QA/QC practices and the relatively poor reconciliations/observed blasthole vs. exploration comparison.

• Indicated mineral resources: Blocks in the model estimated using a minimum of three drillholes which are at maximum average distance of 300 ft, and for which the kriging efficiency of the estimate exceeds 0.

o Kriging efficiency (KE) is used as a relative indicator of estimation quality. Even where the drill spacing may meet a reasonable grid with the requisite number of holes, and the grade variance is relatively high, blocks may be assigned Inferred based on the uncertainty this presents using a relatively poor kriging efficiency. This was determined from review of histograms of the KE and the spatial impact of filtering portions of this population on the grade continuity of the blocks.

• Inferred mineral resources: Blocks in the model which have been estimated but do not meet the criteria for Indicated resources within the mineralized carbonatite model.

• Subsequent to this process, the results are manually contoured and smoothed to eliminate artifacts from the scripting process. The final classification results are coded into the block model for reporting.

11.12 Cut-Off Grade and Pit Optimization

A cut-off grade (COG) of 2.18% TREO has been calculated to ensure that material reported as a mineral resource can satisfy the definition of reasonable potential for economic extraction (RPEE). COG input assumptions are shown below in Table 11-5. The COG is based on an equivalent concentrate selling price of US$12,461/dry st of 60% TREO concentrate (a 15% increase to the mineral reserve selling price of US$10,836/dry st of 60% TREO concentrate). The equivalent concentrate price reflects the gross contained value realized from sales of the four individual REO products produced from the onsite separations facility. The equivalent concentrate price is calculated based on (i) the expected percentage distribution of the REO products in the bastnaesite concentrate, (ii) the expected metallurgical recoveries for the separations facility and (iii) the expected sales prices for the REO products.

Pricing is based on a preliminary marketing study as summarized in Section 16 of this report. Additional costs and recovery considerations have been applied to the cut-off grade assumption as a result of this change.

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Table 11-5: Cut-Off Grade Input Parameters

Production	Value	Units
Concentrator Recovery	Variable based on mined grade	%
Target Concentrate Grade	60.0%	% TREO
Pricing
Applied Price(1)	US$/dst conc.	12,461
Ore Rehandling(2)	US$/dst ore processed	1.32
Concentrator Cost	US$/dst ore processed	54.32
General and Administration	US$/dst ore processed	24.62
Separations Cost	US$/dst conc. processed onsite	Variable(3)
Freight and Marketing	US$/dst product sold	163.29

Source: SRK, 2023

⁽¹⁾ This is an equivalent concentrate price that reflects the gross contained value realized from sales of the four individual REO products produced from the onsite separations facility.

⁽²⁾ Pit mining costs were excluded from the COG calculation because all resource blocks are constrained by an optimized economic pit shell. The pit optimization considered all costs, including mining costs.

⁽³⁾ The separations cost per dst of concentrate is dependent on the quantity of processed concentrate per year (i.e., there is a fixed cost and a variable cost).

Mineral resources have been constrained within an economic pit shell based on reserve input parameters as defined in Table 12-1 of this report. Pit slope angles are variable based on geotechnical study inputs, and mining costs are variable based on haulage and pit depth. Pit optimizations were completed using Maptek Vulcan Lerch-Grossman (LG) optimization algorithms. Various scenarios were evaluated yielding a range of revenue factors. For mineral resources, a revenue factor of 1.0 is selected which corresponds to a break-even pit shell at the nominal pricing of US$12,461/dry st concentrate. SRK notes that the pit selected for mineral resources has been influenced by setbacks relative to critical infrastructure such as the tailing storage facility and the REO concentrator. These setbacks are approximately 280 ft, and “heavy” blocks or extreme densities were assigned to these areas in pit optimization to avoid the optimization mining these areas. Removal of these constraints would increase the overall volume of the pit and thereby the resource. SRK is of the opinion that these constraints are reasonable and in line with the overall determination of RPEE.

Figure 11-19 shows the extents of the optimized pit shape used for resources.

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Source: SRK, 2024

Figure 11-19: Extents of Optimized Pit Shape Relative to Surface Topography

11.13 Mineral Resource Statement

The Mineral Resources are reported in accordance with the S-K regulations (Title 17, Part 229, Items 601 and 1300 until 1305). Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resource will be converted into Mineral Reserves. The Mineral Resource modelling and reporting was completed by SRK and are summarized in Table 11-6. The reference point for the mineral resources is in situ material.

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Table 11-6: Mineral Resource Statement Exclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2023

Category	Resource Type	Cut-Off   TREO%		Mass (million  sh. ton)		Average Value (%)
							TREO(1)	La2O3(2)	CeO2	Pr6O11	Nd2O3	Sm2O3
Indicated	Within the Reserve Pit		2.18		0.94		2.31	0.75	1.15	0.10	0.28	0.02
	Within the Resource Pit		2.18		0.50		3.56	1.16	1.77	0.15	0.43	0.03
Total Indicated			2.18		1.45		2.75	0.89	1.37	0.12	0.33	0.02
Inferred	Within the Reserve Pit		2.18		6.70		5.52	1.80	2.76	0.23	0.67	0.05
	Within the Resource Pit		2.18		2.40		3.74	1.22	1.86	0.16	0.45	0.03
Total Inferred			2.18		9.10		5.05	1.64	2.52	0.21	0.61	0.05

Source: SRK 2023

⁽¹⁾: TREO% represents the total of individually assayed light rare earth oxides on a 99.7% basis of total contained TREO, based on the historical site analyses.

⁽²⁾: Percentage of individual light rare earth oxides are based on the average ratios; La₂O₃ is calculated at a ratio of 32.6% grade of TREO% equivalent estimated grade, CeO₂ is calculated at a ratio of 49.9% of TREO% equivalent estimated grade, Pr₆O₁₁ is calculated at a ratio of 4.3% of TREO% equivalent estimated grade, Nd₂O₃ is calculated at a ratio of 12.1% of TREO% equivalent estimated grade, and Sm₂O₃ is calculated at a ratio of 0.90% of TREO% equivalent estimated grade. The sum of light rare earths averages 99.7%; the additional 0.3% cannot be accounted for based on the analyses available to date and has been discounted from this resource statement.

General Notes:

• Mineral Resources are reported exclusive of Mineral Reserves.

• Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resources estimated will be converted into Mineral Reserves estimate.

• Mineral Resource tonnage and contained metal have been rounded to reflect the accuracy of the estimate, any apparent errors are insignificant.

• Mineral Resource tonnage and grade are reported as diluted.

• The Mineral Resource model has been depleted for historical and forecast mining based on the September 30, 2023, pit topography.

• Pit optimization is based on an average TREO% equivalent concentrate price of US$12,461 per dry st of 60% TREO concentrate, average mining cost at the pit exit of US$1.70 per dry st mined plus US$0.068 per dry st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$78.94 per dry st ore milled, separations facility costs of US$1,551 per dry st of 60% TREO concentrate treated, freight of US$163 per st of dry product shipped, sustaining capital costs of US$30.48 per dry st of ore mined, and overall pit slope angles of 39° to 45° including ramps.

• The mineral resource statement reported herein only includes the rare earth elements cerium, lanthanum, neodymium, praseodymium, and samarium (often referred to as light rare earths). While other rare earth elements, often referred to as heavy rare earths, are present in the deposit, they are not accounted for in this estimate due to historic data limitations (see Section 9.1.5).

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Resources inclusive of the reserves are stated in Table 11-7.

Table 11-7: Mineral Resources Inclusive of Mineral Reserves for the Mountain Pass Rare Earth Project, September 30, 2023

Material Type	Classification	Mass (million  sh. ton)	TREO(1)  (%)	La2O3(2)  (%)	CeO2  (%)	Pr6O11  (%)	Nd2O3  (%)	Sm2O3  (%)
Stockpile	Measured	0.61	4.33	1.41	2.13	0.19	0.52	0.04
In Situ	Indicated	30.25	6.16	2.01	3.07	0.26	0.75	0.055
	Inferred	9.1	5.05	1.65	2.52	0.22	0.61	0.045

Source: SRK, 2024

⁽¹⁾ TREO% represents the total of individually assayed light rare earth oxides on a 99.7% basis of total contained TREO, based on the historical site analyses.

⁽²⁾ Percentage of individual light rare earth oxides are based on the average ratios; La₂O₃ is calculated at a ratio of 32.6% grade of TREO% equivalent estimated grade, CeO₂ is calculated at a ratio of 49.9% of TREO% equivalent estimated grade, Pr₆O₁₁ is calculated at a ratio of 4.3% of TREO% equivalent estimated grade, Nd₂O₃ is calculated at a ratio of 12.1% of TREO% equivalent estimated grade, and Sm₂O₃ is calculated at a ratio of 0.90% of TREO% equivalent estimated grade. The sum of light rare earths averages 99.7%; the additional 0.3% cannot be accounted for based on the analyses available to date and has been discounted from this resource statement.

General Notes:

• Mineral Resources are not Mineral Reserves and do not have demonstrated economic viability. There is no certainty that all or any part of the Mineral Resources estimated will be converted into Mineral Reserves estimate.

• Resources stated as contained within a potentially economically minable open pit stated above a 2.18% TREO Equivalent cut-off.

• Mineral Resource tonnage and contained metal have been rounded to reflect the accuracy of the estimate, any apparent errors are insignificant.

• Mineral Resource tonnage and grade are reported as diluted.

• The Mineral Resource model has been depleted for historical and forecast mining based on the September 30, 2023, pit topography.

• Pit optimization is based on an average TREO% equivalent concentrate price of US$12,461 per dry st of 60% TREO concentrate, average mining cost at the pit exit of US$1.70 per dry st mined plus US$0.068 per dry st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$78.94 per dry st ore milled, separations facility costs of US$1,551 per dry st of 60% TREO concentrate treated, freight of US$163 per st of dry product shipped, sustaining capital costs of US$30.48 per dry st of ore mined, and overall pit slope angles of 39° to 45° including ramps.

• The mineral resource statement reported herein only includes the rare earth elements cerium, lanthanum, neodymium, praseodymium, and samarium (often referred to as light rare earths). While other rare earth elements, often referred to as heavy rare earths, are present in the deposit, they are not accounted for in this estimate due to historic data limitations (see Section 9.1.5).

11.14 Mineral Resource Sensitivity

In order to assess the impact of COG on contained metal, tonnage, and grade were summarized within the TREO resource pit above a series of TREO cut-offs (Table 11-8 and Table 11-9). As can be observed from these sensitivities, the resource is relatively sensitive to cut-off grade in the 3.0% to 5.0% TREO range, which is shown to be above the COG range of economic interest.

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Table 11-8: TREO Cut-off Sensitivity Analysis Within Resource Pit –Indicated Category

Cut-off Grade  (TREO%)	Short Tons ≥  Cut-off  (million short tons)	Average Grade ≥  Cut-off  (TREO%)	Material Content (%)
0.25	45.57	5.13	99.99
0.50	45.36	5.15	99.96
0.75	44.92	5.19	99.84
1.00	44.31	5.26	99.61
1.25	43.61	5.32	99.27
1.50	42.47	5.43	98.60
1.75	41.43	5.52	97.88
2.00	40.14	5.64	96.83
2.25	38.57	5.78	95.40
2.50	36.73	5.95	93.53
2.75	34.92	6.12	91.50
3.00	32.90	6.32	89.01
3.25	31.01	6.52	86.48
3.50	28.94	6.74	83.49
3.75	27.11	6.95	80.66
4.00	25.43	7.16	77.87
4.25	23.86	7.36	75.11
4.50	22.59	7.53	72.73
4.75	21.36	7.69	70.30
5.00	20.22	7.85	67.92

Source: SRK, 2024

Table 11-9: TREO COG Sensitivity Analysis Within Resource Pit – Inferred Category

Cut-off Grade  (TREO%)	Short Tons ≥  Cut-off  (million short tons)	Average Grade ≥  Cut-off  (TREO%)	Material Content  (%)
0.25	33.72	3.03	99.94
0.50	33.14	3.08	99.71
0.75	32.08	3.16	99.08
1.00	30.44	3.28	97.66
1.25	27.70	3.49	94.58
1.50	26.01	3.63	92.29
1.75	24.52	3.75	89.91
2.00	20.93	4.07	83.33
2.25	18.98	4.27	79.32
2.50	17.52	4.43	75.93
2.75	15.47	4.67	70.66
3.00	13.81	4.89	66.00
3.25	12.22	5.12	61.15
3.50	10.77	5.35	56.37
3.75	9.30	5.62	51.14
4.00	7.41	6.07	43.97
4.25	5.99	6.53	38.28
4.50	5.15	6.89	34.69
4.75	4.11	7.46	29.98
5.00	3.76	7.70	28.30

Source: SRK, 2024

In addition to the sensitivity noted above, SRK notes that pit optimization selection does demonstrate sensitivity to those parameters. At the current pricing, recovery assumptions, infrastructure setbacks, and other parameters, the resource pit excludes mineralized blocks above the COG, and typically located at depth. This volume does not meet the constraining criteria for a mineral resource but are estimated above the economic COG are termed “mineralized material”. The relationship to the pit

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shape and non-resource, above COG blocks are shown in Figure 11-20. A summary of mineralized material above COG and external to the constraining resource pit is summarized in Table 11-10.

Table 11-10: Mineralized Material External to Resource Pit

Resource Shell	Relative Confidence	Mass (million  sh. ton)	Average Value  TREO (%)
External	Indicated	8.8	4.30
	Inferred	8.0	3.57

Source: SRK, 2024

Note: Mineralized material does not meet the SEC definition for mineral resources.

The terms “indicated” and “inferred” are not a measure of relative confidence in block tons and grade and do not suggest the material meets the definition for a mineral resource.

Source: SRK, 2024

Figure 11-20: Mineralized Material >= 2.18% TREO and External to Resource Pit Shell

11.15 Assumptions, Parameters, and Methods

SRK uses a comprehensive set of assay analyses and ratio assumptions for individual light rare earth oxides to manually back-calculate rare earth grades and contained metal, as previously described in Section 9.1.4. Based on a statistical review of these analytical data, SRK is of the opinion that the low variances and numerical ranges of these ratios provide a reasonable assessment of individual metals within the TREO estimate, and that these calculations are suitable for resource reporting.

The mineral resource reported herein is subject to potential change based on changes to the forward-looking cost and pricing assumptions as disclosed in this report.

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Extraction of this resource is dependent on modification of current permitted boundaries for the open pit. It is MP Materials’ expectation that it will be successful in modifying these permit conditions. In SRK’s opinion, MP Material’s expectation in this regard is reasonable.

A portion of the resource pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit would only include waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume MP Materials will be able to negotiate a similar agreement.

SRK is of the opinion that the reported mineral resources would not be materially affected by current environmental, permitting, legal, title, taxation, socio-economic, marketing, political, or any other relevant factors. Should any of these factors change in the future, it is SRK’s expectation that the mineral resources may be impacted.

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12 Mineral Reserve Estimate

SRK developed a life-of-mine (LoM) plan for the Mountain Pass operation in support of mineral reserves. MP Materials will operate an on-site separations facility at the Mountain Pass site that will allow the Company to separate bastnaesite concentrate into four individual REO products for sale (PrNd oxide, SEG oxalate, La carbonate/La oxide, and Ce chloride). For economic modeling purposes, a combination of concentrate sales and separated product sales was assumed for Q4 2023 through Q4 2024 while the separations facility ramps up to full capacity. From 2025 onward, it was assumed that all concentrate will be fed to the separations facility. Forecast economic parameters are based on current cost performance for process, transportation, and administrative costs, as well as a first principles estimation of future mining costs. Forecast revenue from concentrate sales and individual separated product sales is based on a preliminary market study commissioned by MP Materials, as discussed in Section 16 of this report.

From this evaluation, pit optimization was performed based on an equivalent concentrate price of US$10,836 per dry st of 60% TREO concentrate. The equivalent concentrate price reflects the gross contained value realized from sales of the four individual REO products produced from the onsite separations facility. The equivalent concentrate price is calculated based on (i) the expected percentage distribution of the REO products in the bastnaesite concentrate, (ii) the expected metallurgical recoveries for the separations facility and (iii) the expected sales prices for the REO products. The results of pit optimization guided the design and scheduling of the ultimate pit. SRK generated a cash flow model which indicated positive economics for the LoM plan, which provides the basis for the reserves. Reserves within the ultimate pit are sequenced for the full 34-year LoM (Q4 2023 through 2056).

The costs used for pit optimization include estimated mining, processing, sustaining capital, transportation, and administrative costs, including an allocation of corporate costs.

Processing recovery for concentrate is variable based on a mathematical relationship to estimate overall TREO recovery versus ore grade. The calculated COG for the reserves is 2.43% TREO, which was applied to indicated blocks contained within an ultimate pit, the design of which was guided by economic pit optimization.

12.1 Conversion Assumptions, Parameters, and Methods

All conversion assumptions, such as mining dilution, mining recovery, COG calculation, pit optimization, and costs were taken into consideration to calculate the reserve estimate.

The following steps were used to calculate the reserves:

• Apply mining dilution to resource block model (using 3D techniques).

• Compile and confirm costs and process recoveries.

• Input optimization parameters into pit optimizer to calculate nested pits using different rare earth concentrate selling prices (only indicated resources were included in the evaluation).

• Choose a pit optimization shell based on strip ratio, revenue, grade distribution, discounted cash flow, cash costs, equipment sizes, pit footprint, depth of pit, minimum mining widths, COG, processing plant size, and other factors.

• Detailed phase design with ramp access to all benches

• Multiple trade-off mine plans based on different mining rates

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• Detailed truck haulage estimates

• Detailed mine cost estimates based on detailed mine plan

• Discounted cash flow based on all capital and operating cost inputs

• Choose final mine plan and cash flow followed by reported reserves.

The following sections provide a description of how mining dilution was applied and how the in-pit COG was calculated.

12.1.1 Model Grade Dilution and Mining Recovery

The SRK resource block model is based on a sublocked 7.5 ft x 7.5 ft x 7.5 ft block size. The sublocked block model has approximately 3.5% estimated dilution. SRK’s selected SMU is 15 x 15 x 30 ft. SRK ran a comparison between the original block model and the final reserves and determined that dilution is approximately 7.1% and the mining recovery from the reblocking is approximately 95%. Based on site reconciliation, SRK has noted that the grades have been higher than predicted. In SRK’s opinion, there is a potential opportunity to reduce dilution by modeling consistently with the 15 ft x 15 ft x 15 ft SMU however the current mining methodology is based on 30 ft bench height. Figure 12-1 shows side by side comparison of the original sublocked model (pre-diluted) and the final 15x15x30 ft SMU selected diluted block model.

Source: SRK, 2021

Figure 12-1: Side by Side Comparison Non-Diluted (Left) Block Model and Diluted (Right) Block Model

It is SRK’s opinion that the reblocking exercise added sufficient dilution to support the Probable category that has been used for the reserves statement. There is a risk that unmodeled internal dykes could increase dilution locally in some areas; however, the current resource drilling information does not have enough resolution to identify these dykes. MP Materials takes care in the mining operations to exclude dyke material from the ore to the extent possible. Dyke material is identifiable in the blasthole cuttings that are used for grade control, and it is visually identifiable by the loader operators.

12.1.2 Cut-Off Grade Calculation

Table 12-1 shows the parameters used for pit optimization. A selling price of US$10,836 per dry st of equivalent concentrate at 60% TREO was used for estimating reserves. The equivalent concentrate price reflects the gross contained value realized from sales of the four individual REO products produced from the onsite separations facility. The equivalent concentrate price is calculated based on

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(i) the expected percentage distribution of the REO products in the bastnaesite concentrate, (ii) the expected metallurgical recoveries for the separations facility and (iii) the expected sales prices for the REO products. The design of the ultimate reserves pit was guided by economic pit optimization. Indicated blocks mined from within the reserves pit were included in the reserves tabulation if they have sufficient value to pay for ore rehandling, processing (including separations), G&A, and product shipping costs. The COG that meets this value threshold is 2.43% TREO. SRK notes that pit mining costs were excluded from the COG calculation because all reserve blocks are constrained by a designed ultimate pit. The designed ultimate pit was based on economic pit optimization that considered all costs, including mining costs.

Table 12-1: Pit Optimization Inputs

Parameter	Unit	Value
Mining Parameters
Ex-Pit Mining Rate (ore + waste)	Mdst/y	Variable (11 Mdst/y maximum)
Mining Dilution(1)	%	0
Mining Dilution Grade	% TREO	0
Mining Recovery	%	100
Interramp Slope Angles(2)
Azimuth 0° to 110°	degrees	46.0
Azimuth 110° to 270°	degrees	47.0
Azimuth 270° to 300°	degrees	45.0
Azimuth 300° to 0°	degrees	44.0
Processing Parameters
Processing Rate	Dry st/y	863,590
Target Concentrate Grade	% TREO	60.0
Concentrate Moisture	%	9.0
Processing Recovery
>1.5% TREO	%	0.0
1.5% to 2.1% TREO	%	22.0
2.1% to 8.3% TREO	%	Variable Based on Grade
>8.3% TREO	%	70.0
Price
Equivalent Concentrate Price(3)	US$/dry st conc.	10,836
Costs
Mining Cost Base Cost	US$/dst mined (ore and waste)	1.700
Mining Cost 15 ft Adjustment	US$/dst mined (ore and waste)	0.068
Sustaining Capital Costs	US$/dst ore mined	30.48
Concentrator Costs	US$/dst ore processed	54.32
General and Administration	US$/dst ore processed	24.62
Separations Cost	US$/dst conc. processed onsite	1,551
Freight and Marketing	US$/dst product sold	163.29
Royalty	% of gross revenue	-

Source: SRK, 2023

(1): Mining dilution is already built into the resource model and no further dilution was applied.

(2): An azimuth of zero degrees corresponds to north.

(3): The equivalent concentrate price reflects the gross contained value realized from sales of the four individual REO products produced from the onsite separations facility.

12.2 Reserve Estimate

The pit optimization considered only the indicated mineral resource category. The revenue factor 1.0 pit shell is the optimized pit shell that corresponds to 100% of the US$10,836 per dry st selling price selected for reserves estimation. The optimized pit shell selected to guide final pit design was based on a combination of the revenue factor (RF) 0.70 pit (used on the north half of the deposit) and the RF

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1.00 pit shell (used on the south half of the deposit). The inter-ramp angles (IRA) used for the mine design are based on operational-level geotechnical studies and range from 44° to 47°.

Measured resources in stockpiles were converted to proven reserves. Indicated pit resources were converted to probable reserves by applying the appropriate modifying factors, as described herein, to potential mining pit shapes created during the mine design process. Inferred resources present within the reserves pit are treated as waste.

The mine design process results in in situ open pit probable mining reserves of 28.1 million st with an average grade of 6.26% TREO. Additionally, there are 0.6 million st of proven mineral reserves in stockpiles with an average grade of 4.33% TREO. The mineral reserve statement, as of September 30, 2023, for Mountain Pass is presented in Table 12-2. The reference point for the mineral reserves is ore delivered to the Mountain Pass concentrator.

Table 12-2: Mineral Reserves at Mountain Pass as of September 30, 2023, SRK Consulting

Category	Description	Run-of-Mine (RoM)  Million Short Tons (dry)	TREO%	MY%	Concentrate Million  Short Tons (dry)
Proven	Current Stockpiles	0.61	4.33	3.67	0.02
	In situ	-	-	-	-
	Proven Totals	0.61	4.33	3.67	0.02
Probable	Current Stockpiles	-	-	-	-
	In situ	28.08	6.26	6.62	1.86
	Probable Totals	28.08	6.26	6.62	1.86
Proven + Probable	Current Stockpiles	0.61	4.33	3.67	0.02
	In situ	28.08	6.26	6.62	1.86
	Proven + Probable Totals	28.69	6.22	6.56	1.88

Source: SRK, 2023

• Reserves stated as contained within an economically minable open pit design stated above a 2.43% TREO COG.

• Mineral reserves tonnage and contained metal have been rounded to reflect the accuracy of the estimate, and numbers may not add due to rounding.

• MY% calculation is based on 60% concentrate grade of the product and the ore grade dependent metallurgical recovery. MY% = (TREO% * Met recovery)/60% concentrate TREO grade.

• Indicated mineral resources have been converted to Probable reserves. Measured mineral resources have been converted to Proven reserves.

• Reserves are diluted at the contact of the 2% TREO geological model triangulation (further to dilution inherent to the resource model and assume selective mining unit of 15 ft x 15 ft x 30 ft).Mineral reserves tonnage and grade are reported as diluted.

• Pit optimization is based on an average TREO% equivalent concentrate price of US$10,836 per dry st of 60% TREO concentrate, average mining cost at the pit exit of US$1.70 per dry st mined plus US$0.068 per dry st mined for each 15 ft bench above or below the pit exit, combined milling and G&A costs of US$78.94 per dry st ore milled, separations facility costs of US$1,551 per dry st of 60% TREO concentrate treated, freight of US$163 per st of dry product shipped, sustaining capital costs of US$30.48 per dry st of ore mined, and overall pit slope angles of 39° to 45° including ramps.

• The topography used was from September 30, 2023.

• Reserves contain material inside and outside permitted mining but within mineral lease.

• Reserves assume 100% mining recovery.

• The strip ratio was 6.3 to 1 (waste to ore ratio).

• The mineral reserves were estimated by SRK Consulting (U.S.) Inc.

In the opinion of SRK as the QP, the conversion of mineral resources to mineral reserves has been completed in accordance with CFR 17, Part 229 (S-K 1300).

12.3 Relevant Factors

The reserve estimate herein is subject to potential change based on changes to the forward-looking cost and revenue assumptions utilized in this study. It is assumed that MP Materials will ramp up its on-site separations facilities to full capacity by the end of 2024. For economic modeling purposes, a combination of concentrate sales and separated product sales was assumed for Q4 2023 through Q4 2024. From 2025 onward, it was assumed that all concentrate will be fed to the separations facility.

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Full extraction of this reserve is dependent upon modification of current permitted boundaries for the open pit. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the resource pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit would only include waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume MP Materials will be able to negotiate a similar agreement.

SRK is not aware of other existing environmental, permitting, legal, socio-economic, marketing, political, or other factors that might materially affect the open pit mineral reserve estimate.

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13 Mining Methods

The Mountain Pass deposit is mined by open pit mining methods. Surface mining operations include:

• Drilling and blasting to remove overburden material

• Loading and haulage

• General maintenance and services

The mine requires blending of mill ore to ensure that the mill receives a head grade within the operating range of the mill. The MP Materials mining equipment fleet includes wheel loaders, trucks, dozers, and graders. Maintenance shops are available at the mine site to service mine equipment.

The open pit is located in gently undulating topography intersecting natural drainages that require small diversions to withstand some rainfall events during the summer months. Waste dumps are managed according to the Action Plan (AP), are located on high ground, and are designed for control of drainage (contact water) if required. Some small diversions are already in place; however, additional diversions will need to be established.

The open pit that forms the basis of the mineral reserves and the LoM production schedule is approximately 3,100 ft from east to west and 3,800 ft from north to south with a maximum depth of 1,400 ft. Total LoM pit mining is estimated at 203.9 million st comprised of 28.1 million st of ore and 175.8 million st of waste, resulting in a strip ratio of 6.3 (waste to ore). Additional mill feed is sourced from existing stockpiles (0.6 million st). LoM mill feed grade averages 6.22% TREO yielding over 1.88 million dry st of recoverable 60% TREO concentrate.

SRK designed four pit pushbacks that adhere to proper minimum mining widths. Bench sinking rates are approximated to no more than six benches per year per pushback.

Figure 13-1 illustrates the site layout and final pit design.

SRK’s evaluation included:

• Open pit block model incorporating dilution and other required mining variables

• Pit optimization analysis and sensitivities

• Pit and phase designs

• Bench-based LoM production schedule integrated with the processing schedule

• Low-grade stockpile design

• Waste dump design

• Quarterly progression of pit and waste dumps for developing annual haulage cycle time estimation

• Fleet estimation of open pit equipment based on the mining production schedule

Results developed included estimated equipment fleet requirements, sustaining capital costs, and operating costs.

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Source: SRK, 2023

Figure 13-1: Final Pit Design and Site Layout

13.1 Parameters Relevant to Mine or Pit Designs and Plans

13.1.1 Geotechnical

For pit optimization and phase design, SRK used recommendations for pit slope inter-ramp angles (IRA) between 44° and 47° for all phases. These angles are based on results of a geotechnical study that was prepared by Call & Nicholas, Inc. in 2022 (CNI, 2022). Figure 13-2 shows the final IRA recommended by CNI, 2022 for the phase and final pit designs. SRK’s mine design work was based on these IRA’s, as presented in Table 13-1.

The recommended slope angles are controlled by the bench and inter-ramp stability, for all design sectors with the exception of the northwest (azimuth 300-0). An 80% catch bench reliability for the 60 ft high double bench configuration was used to determine the bench and inter-ramp slope angles. Overall slope wall factor of safety (FoS) exceeds 2.0 for the stability analysis sections analyzed by CNI. CNI has recommended that no critical infrastructure be placed within 200 ft of the final pit crest. SRK has reviewed and concurs with this recommendations. Locally, a minimum FoS was calculated for critical surfaces in the upper 2 to 3 benches of alluvium. All FoS calculated meet or exceed the guidelines for open pit slope stability guidance for wall stability (Read & Stacey, 2009).

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NO Critical Infrastructure within 200 ft. of pit crest. ISA=44 ISA=45 ISA=46 ISA=147 200ft.

Source: CNI, 2022

Note: ISA is equivalent to IRA

Figure 13-2: Recommended Double Bench IRA from CNI

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Rock Mass Characterization

The rock mass consists of several different engineering geologic properties, including Carbonatite, Breccia, and Gneiss/Schist. The carbonatites are strong, dense, coarsely crystalline rocks and carbonatites which comprise most of the north, east, and south walls. The rock mass is strongly foliated with a dip to the west-southwest at approximately 50° to 70°. Distinct sets of cross joints are observed orthogonal to the main foliation; however, the orientation of these joints varies over short distances.

Intact strengths have been estimated by both point load testing (Vector, 1995) and by uniaxial compressive strength (UCS) testing of surface samples conducted by CNI in 2011. Intact UCS values range from 10,000 to 20,000 pounds per square inch (psi).

Rock Quality Designation/Rock Mass Rating

The Rock Quality Designation (RQD) ranges from 20 to 80 as observed by both CNI and Golder in the pit slope walls. An average RQD value of 50 is appropriate for characterizing the rock mass. A full Rock Mass Rating (RMR), including analysis of drill core at depth in the final walls, has not been completed but is estimated by SRK to be in the range of RMR 50 to 60. Four geotechnical studies with a defined rock mass for stability analyses have been completed to date on the Project. These studies include studies by Call & Nicholas, in 2011, 2020, and 2022. Prior work was done by Golder Associates in 2002 and Vector Engineering in 1995.

SRK has reviewed CNI slope angle recommendations (CNI, 2022) and consider them valid and appropriate for slope design. Pit slope angles have been determined using the recommendations from the CNI report assuming an 80% catch bench reliability.

SRK conducted a site visit on September 25, 2019, to observe the conditions of the Mountain Pass open pit. Key observations included successful double benching on the west wall with greater than 80% catch reliability in slopes excavated by MP Materials.

Open Pit Mine Design Parameters

The recommended slope angles for the Mountain Pass open pit were developed from the review of the 2022 CNI slope stability report and a review of the slope conditions of the west wall excavated by MP Materials. The recommended slope design parameters are listed in Table 13-1, and the slope design sectors are graphically illustrated on Figure 13-2.

Table 13-1: Recommended Slope Design Parameters

Open Pit Parameters
Bench increment	15 ft
Bench height	30 or 60 ft
Bench face/batter angle (BFA)	66° to 68°
Design bench/berm width (60 ft high bench)	30 to 36 ft
Minimum bench width (modified Ritchie Criteria, 30 and 60 ft high)	15 to 24 ft
Maximum IRA by design sector	44° to 47°
Maximum overall slope angle (OSA)	45°
Design Criteria
Minimum factor of safety (FoS)	2.0

Source: SRK, 2023

Slope design constraints assume a 15 ft model block height. Mining production will be conducted primarily on 30 ft bench heights. Most areas of the mine are in competent rock mass, and it is envisioned that in these areas the mining in the final wall will be finished to a 30 ft face or a 60 ft face

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height. Using a multiple-bench final wall configuration permits a steeper IRA in competent ground. The maximum inter-ramp slope height (bench stack height) is 500 ft. A geotechnical berm, or haul ramp, with a minimum width of 65 ft is required between bench stacks.

The minimum catch bench width is developed using the modified Ritchie Criteria (Ryan and Pryor, 2000). The minimum catch bench width for a 60 ft high bench face is 24 ft using the Ritchie Criteria. For a 30 ft high bench, the minimum width is 15 ft.

Bench face angles vary by sector and are based on average obtained values by mapping. The measured bench face angle using highwall controlled blasting procedures results in average bench face angles ranging from 66° to 68°. For the given slope design parameters and limited subsurface data, dual ramp access is required to ensure access to ore material for each mining phase. With the ramps and the recommended IRAs, the final wall overall slope angle maximum is 45°. Stability of the pit slope, including hydrogeological inputs, is documented in the CNI, 2022 report. SRK has reviewed the results, and stability of the pit slope using these design parameters meets a slope acceptance criterion with a minimum FoS of greater than 2.0. These FoS results are within the guidelines of the current reclamation plan, and also meet the criteria outlined in Guidelines for Open Pit Slope Design (Read & Stacey, 2009).

Table 13-2 lists the CNI recommended slope design parameters by wall sector, as illustrated on Figure 13-2.

Table 13-2: CNI Final Recommended Slope Design Parameters by Design Sector

Mine Planning Azimuth				Wall DDR (Clockwise)				Bench Height (ft)		Design IRA (°)		BFA (°)		Design Layout Bench Width (ft)
Start		End		Start		End
	110		270		290		90		60		47		70		34.1
	270		300		90		120		60		45		71		39.3
	300		0		120		180		60		44		68		37.9
	0		110		180		290		60		46		68		33.7

Source: CNI, 2022

MP Materials has been using controlled wall blasting in order to achieve the recommended bench configurations. Trim shots are used against final walls. In SRK’s opinion, the blasting procedures in place are sufficient to achieve the recommended slope design parameters.

CNI recommended a slope offset for mine facilities, including the concentrator, paste tailings plant, process plant, and water storage tanks, of 200 ft. CNI recommends if the pit crest is within 200 ft of critical infrastructure, the recommended IRA is 44° for at least four benches (120 ft). Below these benches, the IRA may be increased to 46°. SRK concurs with this recommendation.

As a part of the CNI Geotechnical study (CNI, 2022), Three multi-level piezometers with a total of nine transducers were reviewed to characterize the current phreatic surface elevation. An Environmental Impact Report written in 1996 (ENSR, 1996) shows that groundwater flows Northwest to Southeast in the pit area. The stability analysis incorporates modeled pore pressures based on the piezometric data.

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Geotechnical Recommendations

Routine geotechnical slope monitoring, data collection, and analysis should continue. MP Materials should review geotechnical parameters and optimize the mine plan prior to starting new phases based on this review.

13.1.2 Hydrogeological

Groundwater in the vicinity of the mine occurs within coarse unconsolidated alluvial sediments and within underlying fractured Precambrian bedrock. In general, most of the groundwater flows eastward through the alluvium toward the Ivanpah Valley and westward toward the Shadow Valley as shown schematically in Figure 13-3.

Source: Draft EIR (1996)

Figure 13-3: Idealized Cross-Section Through Mine Area and Adjacent Valleys

The surface geology of the site is characterized by partially lithified, cemented Tertiary to Quaternary age alluvial deposits and debris flows in the southwest and central areas, Precambrian gneissic bedrock outcropping in the north, east, and southeast, and by Precambrian gneiss, terrace gravels, and recent alluvial deposits in the wash areas in the northwest, east and southeast. Bedrock at the site consists of Precambrian metamorphic and younger intrusive rocks. The older metamorphic rocks consist primarily of granitic and mafic gneiss. The main igneous bodies at the site, which have intruded the older metamorphic complex, consist of shonkinite and syenite stocks and associated carbonatites. The dominant structural fabric as represented by faulting, foliation, jointing, and fracture-controlled dikes, trends northwest and dips steeply to the northeast or southwest.

Extensive faulting in the mountain ranges is also hydrologically significant. Several lateral transverse faults have been mapped in the area. This can lead to sharp contrasts in bedrock permeability-fracturing can be extensive along fault zones and affect permeability. Often faults act as barriers normal to flow and as groundwater conduits parallel to flow.

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Major faults were identified and incorporated into the numerical groundwater model developed by Geomega in 2000 (Geomega, 2000) for the early stage of open pit excavation. The model simulated several faults as flow barriers, including two in the pit area:

• Clark Mountain fault, a normal/reverse fault

• South fault, a left lateral fault

• North fault, a left lateral fault

• Middle fault, a left lateral fault

• East Ore Body fault, a normal fault

• P-16 Fault, a normal fault

Additionally, the Geomega model simulated the Celebration fault, a left lateral fault with some normal movement, as a conduit to flow.

The location of these faults is shown in a simplified surface geological map and conceptual hydrogeologic cross-section made by Geomega (2000) in Figure 13-4 and Figure 13-5, respectively.

Source: Geomega (2000)

Figure 13-4: Simplified Surface Geology

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Source: Geomega (2000)

Figure 13-5: Conceptual Hydrologic Cross-Section

Hydraulic conductivity values of sediments and bedrock units exhibit considerable variability depending both on the lithology and the degree of cementation, fracturing, or other secondary permeability development. Groundwater permeability within the bedrock is fracture-controlled. Hydraulic conductivity values in fractured zones range up to 17 feet per day (ft/d), while those in less fractured zones range up to 0.04 ft/d (GSi/water, 1991). Within the older alluvium, variation may result from differing degrees of cementation and clay content associated with alternating sequences of alluviation and debris flows. The older alluvium deposits have been found to be significantly less permeable than the recent alluvium, exhibiting hydraulic conductivity values on the order of 0.03 to 0.003 ft/d (GSi/water, 1991). The recent wash deposits are the most permeable at the site, exhibiting hydraulic conductivity values in order of tens ft/d (SRK, December 1985).

The hydraulic parameters of the hydrogeological units were tested by pumping tests, slug tests, and packer testing. Table 13-3 summarizes statistics of the measured hydraulic conductivity values.

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Table 13-3: Summary of Measured Hydraulic Conductivity Values

Hydrogeological Unit	Number of Tests		Hydraulic Conductivity (ft/d)
			Min		Max		Average		Geomean
Shallow Alluvium		2		15.6		85.0		50.3		36.4
Old Alluvium		27		0.003		6.8		1.1		0.16
Bedrock		45		0.002		56.7		3.5		0.41

Source: Compiled by SRK using data in Geo-Logic (March 2023)

Figure 13-6 shows the distribution of measured hydraulic conductivity values per depth:

Source: Compiled by SRK using data in Geo-Logic (March 2023)

Note: Error bars show tested intervals.

Figure 13-6: Measured Hydraulic Conductivity Values per Depth

Table 13-3 and Figure 13-6 indicate:

• Large variability in hydraulic parameters (up to 4 orders of magnitude)

• Relatively large hydraulic conductivity for bedrock where the open pit is being excavated (geometric mean is 0.4 ft/d)

• General trend of decreasing bedrock hydraulic conductivity with depth

• Testing of the shallow bedrock with limited tests completed below the depth of 250 ft

The groundwater levels around open pit and other mine facilities have been observed by monitoring wells. Their location, currently measured water table elevation and direction of groundwater flow is shown in Figure 13-7.

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Source: Geo-Logic (July 2023)

Figure 13-7: Location of Monitoring Wells, Measured Water Table Elevation, and Direction of Groundwater Flow (as Q2 2023)

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Figure 13-7 and Geo-Logic (July 2023) indicate:

• Groundwater generated by recharge from precipitation at the Clark Mountains north of the mine flows to the southeast and discharges in alluvial fan deposits of the Ivanpah Valley and Shadow Valley to the east and west, respectively.

• The open pit creates a local cone of drawdown due to pumping from two pit dewatering wells. The estimated lowest water table elevation within the pit is about 4,400 ft amsl.

• Measured groundwater levels at the site during the first 2023 monitoring period reflect a continued long-term decreasing trend, and several have become dry. The steady decline in water levels extends back to a particularly wet year in 2005 when there was a marked increase in water levels at the site.

Water level elevations in the walls of the proposed ultimate pit were measured in the piezometers recently installed in geotechnical core holes. Their location and measured water levels are shown in Figure 13-8.

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Source: CNI (January 2022)

Note: The existing pit is shown in the right figure in green, with the phase 10 pit evaluated by CNI– in grey. Ultimate pit shells proposed by SRK are not shown – they consider deepening of the pit to 3,740 ft amsl.

Figure 13-8: Location of Piezometers and Measured Water Levels in Pit Walls

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Figure 13-8 indicates:

• The lower part of the water table in the pit area is slightly below 4,400 ft amsl

• Presence of a downward hydraulic gradient in the eastern wall (recharge area) and an upward gradient in the western wall (toward the discharge area).

The location of industrial and domestic water supply wells (both historic and existing) with the mine facilities is shown in Figure 13-9.

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Source: Geo-Logic (July 2023)

Figure 13-9: Location of Industrial and Domestic Water Supply Wells and Mine Facilities

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Mine Dewatering

• Mine pit dewatering is accomplished using one or two dewatering wells at the bottom of the mine pit.

• Historically, dewatering of the open pit was done by one dewatering well. The pumping rate was about 36 gpm during 1987 through 1991. From June to November 1993 the pit well pumped an average 127 gpm to depress the water table below the 4,510 ft mining level.

• Two extraction dewatering wells (PEW-1 and PEW-2) were installed at the bottom of the pit within fractured bedrock in 2018 and drilled to the depths of 215 m and 162 m, respectively. The screen depth intervals in PEW-1 are from 115 to 214 m, and in PEW-2 are from 60 to 160 m. The location of these wells is shown in Figure 13-5.

• A summary of pit water production during the first half of 2023 is provided in Table 13-4. Pit dewatering yielded approximately 19.1 million gallons during the last two quarters of 2023. The pumping rate varied from 28 to 112 gpm with an average rate of 74 gpm. The pit water was used exclusively for dust control on the mine’s roads. Pumping from wells PEW-1 and PEW-2 allows the mine to maintain local containment of groundwater (shown in Figure 13-5).

Table 13-4: Summary of Pit Water Production in the First Half of 2023

Month of 2023	The Volume of Pumped Water (gal)	Average Pumping Rate (gpm)
January	1,255,700	28.1
February	2,413,900	59.9
March	2,494,000	55.9
April	4,857,300	112.4
May	4,016,500	90.0
July	4,080,300	94.5
Average	3,186,283	73.5

Source: Geo-Logic (July 2023)

CNI proposed to drill a new pumping well to the northwest from the current pit to the bottom elevation of 3,440 ft amsl and a monitoring well in the center of the pit with 3 nested grouted-in transducers for conducting long-term pumping test (CNI, November 2022). The locations of the pumping and monitoring wells are shown in Figure 13-10 and Figure 13-11.

In SRK’s opinion, this pumping test can be successful if bedrock to the elevation of 3,440 ft amsl is permeable and sufficient drawdown will propagate toward the proposed well. The total transmissivity of bedrock would be measured without the possibility of differentiating it per depth. If MP Minerals proceeds with the suggested CNI plan to drill pumping and monitoring wells, SRK strongly recommends adding spinner logging testing of the pumping well to allow at least preliminary re-distribute measured total transmissivity per depth.

Available data shown in Figure 13-4 suggest that hydraulic conductivity values decrease with depth and only isolated interval testing can verify this trend, considering that ultimate pit bottom elevation evaluated by SRK will reach an elevation of about 3,740 ft amsl.

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Source: CNI (November 2022)

Figure 13-10: Location of Proposed Pumping and Monitoring Wells by CNI Shown in Plan-View

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Source: CNI (November 2022) with modification by SRK

Figure 13-11: Location of Proposed Pumping and Monitoring Wells by CNI Shown on Cross-Section

The proposed deepening of the bottom of the pit to the ultimate elevation of 3,740 ft amsl will increase dewatering rates compared to currently observed. The major sources of groundwater inflow into the proposed pit would be:

• Fractured zones of the bedrock (location of these zones at the depth is currently unknown).

• Old alluvium sediments to the southeast (as shown in Figure 13-11); these sediments need to be dewatered by pumping well(s) to avoid groundwater spillover into the pit.

Most likely, pit dewatering can be handled by a system of bedrock pumping wells (in-pit, similar to existing wells PEW-1 and PEW-2, or perimeter wells drilled to the greater depths) and residual passive inflow captured by in-pit sumps).

It should be noted that:

• Hydrogeological conditions of the bedrock have not been tested at the proposed depth of the future pit. Packer testing was not completed in geotechnical and exploration core holes.

• Future effectiveness of in-pit pumping wells is unclear considering the deepening of the existing pit bottom by an additional 585 ft.

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• The numerical groundwater model of the mine area developed by Geomega in 2000 has not been updated to allow the prediction of:

o Dewatering requirements during future mining conditions

o Pit lake infilling during post-mining conditions

SRK recommends that MP Minerals:

• Conduct additional hydrogeological studies of the deep part of the bedrock to the elevation of the proposed bottom of the pit (3,000 ft amsl) by conducting packer-isolated tests in three or four core holes defining bedrock permeability and dewatering targets (where and to what depth dewatering wells can be installed). The strings of vibrated wire piezometers (similar to those installed by CNI) are also recommended in these core holes to better define vertical hydraulic conductivity and the hydrogeological role of encountered faults.

• If zones of significant permeability are found by packer testing, pumping wells with long screens should be drilled targeting these zones with the drilling of pilot holes prior to their construction. Spinner logging needs to be done within the screen intervals of these pumping wells.

• Update or develop new numerical groundwater flow to predict inflow to the proposed pit and better define:

o Dewatering requirements

o Pore pressures in pit walls and the potential necessity to reduce them by installation of horizontal drain holes from pit benches (if required by geotechnical conditions of the slopes)

o Propagation of the drawdown cone during both mining and post-mining conditions (including pit lake infilling) to evaluate the potential impact on the groundwater system because of the continued deepening of the open pit

Water Supply

MP Minerals maintains and operates two water supply wellfields for portable and process water. The Ivanpah well field, established in 1952, is located on private land eight miles east of the mine site and consists of six freshwater-producing wells, three booster stations, and associated pipelines. The Shadow Valley well field, established in 1980, is located 12 miles west of the mine site and consists of four wells of which three are on public land and one on private land, a single booster station, and associated pipelines. The water supply wells are completed within coarse alluvial sediments.

The amount of freshwater consumed by the facility in 1996 was approximately 850 gpm from both wellfields. The five-year annual average between 1993 and 1997 was 795 gpm. As part of the comprehensive plan for continued operations, MP Materials placed emphasis on on-site management and treatment of process water and maximizing reuse (SRK, 2010).

As the water supply systems have consistently produced much larger amounts of fresh water for the facility in the past, the water supply is not anticipated to be problematic.

13.2 Pit Optimization

SRK completed a pit optimization exercise to provide the basis for the final LoM reserve pit design. This process utilizes initial approximated assumptions for the LoM production such as an average overall slope angle, typical production costs and typical process recoveries, as discussed below. It is important to note that these parameters do not exactly reflect the final reserve assumptions as this process is an interim step that precedes these final reserve calculations. Therefore, there are typically

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small differences between initial pit optimization assumptions and final reserve assumptions on items such slope design and costs, which are calculated as part of the final mine design process.

For the purposes of this analysis, SRK utilized Whittle^™ software which uses a Lerchs-Grossmann algorithm to produce a series of nested pit shells which are derived by incrementally changing revenue assumptions. These incremental changes are referred to as Revenue Factors (RF) with, for example, a RF 1.0 reflecting a pit requiring 100% of the assumed base case revenue to be economic. In comparison, a RF 0.9 pit only requires 90% of the base case revenue to be economic, and this pit is inherently smaller than the RF 1.0 pit and hence is nested within it.

13.2.1 Mineral Resource Models

The current block model block sizes are 15 ft by 15 ft by 30 ft (Table 13-5). SRK applied dilution to the edge blocks based on the percentage of waste material within this block. This was done by performing a reblocking calculation on all the blocks. SRK is of the opinion that the grades will vary considerably at the local scale when mining.

Table 13-5: Block Model Block Sizes

Item	Main Pit Area
X (ft)	15
Y (ft)	15
Z (ft)	30

Source: SRK, 2023

The resource block model was imported into Whittle^™ and Maptek Vulcan LG and verified against the original mineral resource block model (block model), created in Vulcan^™. The Vulcan^™ block model subsequently was coded in preparation for optimization. This included diluting the block model to account for mining practices. The verification process indicated no material changes to the block model tonnages and grade during the process of importing into Whittle^™.

13.2.2 Topographic Data

SRK was provided a September 30, 2023, surface to be used in the reserve calculation. The site uses a DJI Phantom 4 RTK Drone, Pix4D, and Maptek’s I-Site software to provide detailed surveys.

13.2.3 Pit Optimization Constraints

The Mountain Pass pit design combines current site access, mining width requirements, and generalized geotechnical parameters to evaluate the possibility for full extraction of resources through open pit techniques. Restrictions were placed on the pit optimization to prevent the optimized pit shell from encroaching on the concentrator and tailings storage facility.

The optimization process was restricted to indicated resources. There are no pit resources classified as measured. For the purpose of the optimization, there were no production or processing limits used within Whittle^™, and all material not classified as indicated was treated for calculation purposes as waste.

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13.2.4 Pit Optimization Parameters

Mining Dilution

The block model is based on 15 ft by 15 ft by 30 ft blocks. Where the interpretation of the mineralized rock intersects a block model block centroid, the block within the mineralized shape is recorded. The flagging of ore type is based on block centroid and accounts for the location and placement of the ore contact. Because the contact of waste and ore is not always clearly visible, dilution is expected and has been accounted for. Average dilution across the deposit results in a 3.5% reduction in ore grades.

The Whittle^™ optimization software used settings of 0% mining dilution and 100% ore recovery (as this was pre-coded into the block model). These parameters were supplied by the client but are considered by SRK to be reasonable because the imported block model was already diluted.

Discount Rate

The pit optimization process used a 6% discounting factor. Inflation was not factored into the costs or the selling price used in the analysis.

Geotechnical Parameters

For the pit optimization, SRK used a variable overall slope angle between 39° and 45°, which approximates the inclusion of ramps (the pit optimization process cannot include actual ramp design so this must be approximated). The final pit design, including the location of the ramps will differ slightly from the pit optimization initial assumptions.

Revenue

SRK utilized a base case selling price of US$10,836/dry st for a 60% TREO equivalent concentrate. The equivalent concentrate price reflects the gross contained value realized from sales of the four individual REO products produced from the onsite separations facility. The equivalent concentrate price is calculated based on (i) the expected percentage distribution of the REO products in the bastnaesite concentrate, (ii) the expected metallurgical recoveries for the separations facility and (iii) the expected sales prices for the REO products.

Royalties

No royalties have been applied to the optimization.

Mining Costs

SRK reviewed MP Materials’ recent actual costs and modified the pit optimization costs based on prior experience with similar projects. A base mining cost per short ton at the pit exit elevation has been applied for all material. The base mining cost is US$1.700/st. For each 15 ft bench that is mined above or below the pit exit elevation, an incremental cost of US$0.068/st was added. Subsequent to pit optimization, SRK prepared a first principles mining cost model, the results of which were used for economic modeling.

Recoveries

The current forecast mill recoveries are variable based on ore grade, and the concentrate grade target is 60% TREO. SRK is using the following equation for the mass yield calculation: MY% = (TREO% * Met Recovery)/60%.

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Other Input Parameters

Table 12-1 presents the full list of pit optimization parameters.

13.2.5 Optimization Process

As a result of the pit optimization, the relationship of potential pit shells is based on stripping ratio variability and subject to the base case selling price of US$10,836/dry st (60% TREO equivalent concentrate). By looking at the relationship of ore to waste and the associated best-case and worst-case cash flows generated at each incremental pit, the risk profile and revenue generating potential of the deposit can be estimated.

To estimate the LoM pit utilized as the basis for the final reserve pit design, a series of nested pit shells were calculated over a range of Revenue Factors (RF). Each of the nested pit shells were generated based on the maximum pit value calculated for the applicable RF. The generated nested pit shells increase in size as the RF and maximum pit value also increase.

The final pit design will not exactly match this optimization output and will often include a small amount of material outside of this estimated LoM pit.

13.2.6 Optimization Results

Pit optimization results are presented in Table 13-6. The optimized pit shell selected to guide final pit design was based on a combination of the RF 0.70 pit (pit shell 11, used on the north half of the deposit) and the RF 1.00 pit shell (pit shell 17, used on the south half of the deposit).

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Table 13-6: Mountain Pass Pit Optimization Result Using Indicated Classification Only

Pit	Revenue Factor		Concentrate (60% TREO) Equivalent Price (US$/dry st)		Strip Ratio		Total Mined (million st)		Ore (million st)		Waste (million st)		Concentrate Produced (thousand st)		MY%			TREO Dil%
1		0.2	$	2,167		0.09		0.0		0.0		0.0		1.2		20.76	%		17.81
2		0.25	$	2,709		0.49		6.5		4.4		2.2		459.9		10.50	%		9.18
3		0.3	$	3,251		2.51		58.9		16.8		42.2		1,360.2		8.11	%		7.35
4		0.35	$	3,793		3.32		104.2		24.1		80.1		1,776.1		7.37	%		6.80
5		0.4	$	4,334		3.70		126.5		26.9		99.5		1,911.2		7.10	%		6.60
6		0.45	$	4,876		3.99		140.1		28.1		112.0		1,965.2		7.00	%		6.53
7		0.5	$	5,418		4.22		150.3		28.8		121.5		1,995.2		6.92	%		6.48
8		0.55	$	5,960		4.23		151.4		28.9		122.4		1,998.7		6.91	%		6.47
9		0.6	$	6,502		4.34		156.0		29.2		126.8		2,008.2		6.88	%		6.45
10		0.65	$	7,043		4.37		157.3		29.3		128.0		2,011.1		6.86	%		6.44
11		0.7	$	7,585		4.49		162.4		29.6		132.9		2,018.9		6.83	%		6.41
12		0.75	$	8,127		4.53		164.1		29.7		134.4		2,021.6		6.81	%		6.40
13		0.8	$	8,669		4.55		165.1		29.7		135.4		2,023.1		6.80	%		6.40
14		0.85	$	9,211		4.62		167.5		29.8		137.6		2,025.2		6.79	%		6.39
15		0.9	$	9,752		4.65		168.9		29.9		138.9		2,027.9		6.78	%		6.38
16		0.95	$	10,294		4.64		169.0		30.0		139.1		2,028.5		6.77	%		6.38
17		1	$	10,836		4.70		171.1		30.0		141.0		2,030.2		6.76	%		6.37
18		1.05	$	11,378		4.71		171.7		30.1		141.6		2,030.8		6.76	%		6.36

Source SRK, 2023

The optimized pit shell selected to guide final pit design was based on a combination of the RF 0.70 pit (pit shell 11 (blue line), used on the north half of the deposit) and the RF 1.00 pit shell (pit shell 17 (yellow line), used on the south half of the deposit)

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Figure 13-12 shows the results of the pit optimization in a pit-by-pit graph.

Source: SRK, 2023

Note: Pit value is pre-capex, pre-tax and assumes a 6% discount rate.

Figure 13-12: Mountain Pass Pit by Pit Optimization Result

Figure 13-13 shows the mineral reserves (red line) versus the mineral resources (magenta line) pit optimization shells.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 167

Source: SRK, 2023

Figure 13-13: Mountain Pass Mineral Reserves Pit (Red Line) and Mineral Resources Shell

      (Magenta Line) Surface Intersection

13.3 Design Criteria

13.3.1 Pit and Phase Designs

Phase designs for the deposit are largely driven by the effective mining width and its influence on access to the resource. The same design parameters used in the final pit design have been incorporated into the phase designs. A total of four phase designs were created for the Mountain Pass pit, all of which fall within the selected optimized pit shell. Figure 13-14 shows the location of each phase.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 168

Source SRK, 2023

Note: Phases 1 through 4 were previously mined.

Figure 13-14: Phase Design Locations

To ensure proper ore exposure and access to different TREO grades, SRK created multiple mining phases. To improve the economics of the Project, phases were divided by following pit optimization shells to ensure that the higher profit pit shells were being mined first.

Figure 13-15 shows the September 30, 2023, starting reserve topography. Figure 13-16 below shows the final pit design.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 169

Source: SRK, 2023

Figure 13-15: Reserve Starting Topography, September 30, 2023

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 170

Source: SRK, 2023

Figure 13-16: Final Pit Design

13.4 Mine Production Schedule

The current LoM plan has pit mining for approximately 26 years (Q4 2023 through 2048), followed by approximately 8 years of processing long-term ore stockpiles (2049 through 2056). The entire reserve is mined by the LoM plan. The average strip ratio is 6.3. A tabulation of annual mining and processing physicals is presented in Section 19 (specifically, Figure 19-9).

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 171

13.4.1 Mine Production

Figure 13-17 to Figure 13-25 present the LoM production schedule and haulage profiles for the Mountain Pass mine. The production schedule is used as the basis of the technical economic model (TEM) and comprises mill feed ore and waste. To ensure proper ore exposure, SRK generated the mine plan using quarterly periods for the duration of the mine life.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 172

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-17: Total Mined Material from the Open Pit (Ore and Waste)

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-18: Ore Mined from the Open Pit

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 173

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-19: Mined Ore Grade

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-20: Rehandled Material

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 174

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-21: Mill Concentrate Production

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-22: Mill Feed Grade

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 175

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-23: Number of Benches Mined

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-24: Haul Truck Cycle Time

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 176

Source: SRK, 2023

Note: 2023 includes only October - December

Figure 13-25: Long-Term Ore Stockpile End of Period Balance

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 177

Grade Control

Grade control provides critical control to ensure that ore and waste are identified at a high resolution prior to mining and then hauled to the appropriate destination (i.e., primary crusher, stockpile, or waste dump). The grade control process is as follows:

• All blastholes will be sampled near the mineralized zones.

• For the 30 ft mining bench height, the following sampling technique will be utilized.

o Drillers/samplers will gather cuttings and define them by their drill hole number and pattern number.

o Samples will be analyzed in a laboratory set up on-site.

• The geologist / mine engineer will build outlines based on the analyzed grade range.

• The geologist and surveyors will place flags in the pattern based on the grade control outlines.

13.5 Waste and Stockpile Design

13.5.1 Waste Rock Storage Facility

The waste rock storage for the Mountain Pass operation has been designed to limit the vertical expansion of the waste dumps and have dump toes located for control of surface run-off. The dumps have also been located in areas that will not be impacted by potential future mining operations.

The mine plan includes full development of the west overburden stockpile, located to the west of the existing open pit. As of September 30, 2023, the remaining, permitted storage capacity of the west overburden stockpile is 3.8 million st.

The total estimated waste rock storage requirement associated with the mine plan is 175.8 million st. Mountain Pass will fill the west overburden stockpile and place the balance of overburden material in the north overburden stockpile and/or the east overburden stockpile. Total estimated waste rock capacities for each dump are provided in Table 13-7.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 178

Table 13-7: Estimated Remaining Storage Capacity for Waste Rock

Dump	Toe Elevation		Volume (million ft3)		Million Short Tons		Years Active
North		4,850		0.8		0.0		2023
		4,900		22.5		1.4		2024
		4,950		62.3		3.8		2024
		5,000		101.8		6.3		2025
		5,050		133.0		8.2		2026
		5,100		139.2		8.6		2028
		5,150		105.6		6.5		2029
		5,200		28.6		1.8		2029
		North Total		593.8		36.6
West		5,000		0.1		0.0		2029
		5,050		25.4		1.6		2029
		5,100		36.1		2.2		2030
		West Total		61.6		3.8
East		4,450		6.0		0.4		2030
		4,500		58.0		3.6		2030
		4,550		139.1		8.6		2031
		4,600		216.6		13.3		2033
		4,650		318.7		19.6		2036
		4,700		405.4		25.0		2039
		4,750		390.8		24.1		2041
		4,800		330.7		20.4		2043
		4,850		262.5		16.2		2046
		4,900		184.6		11.4		2048
		East Total		2,312.4		142.4
All		Total		2,967.8		182.7

Source: SRK, 2023

Figure 13-26 shows the locations of the waste dumps and long-term ore stockpile.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 179

Source SRK, 2023

Figure 13-26: Final Pit Design and Waste Dump Locations

13.5.2 Stockpiles

The long-term ore stockpile will hold a maximum of about 7.5 million st of ore, all of which will eventually be sent to the primary crusher. The long-term ore stockpile is located to the northwest of the pit.

The current operation uses four low-capacity RoM blending stockpiles in front of the primary crusher. These stockpiles are small, and the total capacity for all of them is less than 50,000 st. The operation plans to continue this practice in the future.

13.6 Mining Fleet and Requirements

13.6.1 General Requirements and Fleet Selection

Mountain Pass is an open pit mine using front-end wheel loaders loading haul trucks for waste and ore haulage. The operations are described further in the following sections.

Mining activities include drilling, blasting, loading, hauling and support activities. Ore will be sent to the primary crusher RoM stockpiles for near-term blending or to long-term stockpiles for processing later in the mine life. Waste dumps will be used for material below the cut-off grade.

The loading, hauling, and support equipment operations are performed with a fleet that is owned and operated by MP Materials. Drill and blast operations are performed by a contractor, and this will continue for the foreseeable future. The primary loading equipment is front-end loaders (15 yd³), which were selected for operational flexibility. Rigid frame haul trucks (102 wet st) were selected to match with the loading units.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 180

The mine equipment fleet requirements are based on the annual mine production schedule, the mine work schedule, and shift production estimates. The equipment fleet requirements are further discussed in the individual sections that follow in this report.

All mine mobile equipment is diesel-powered to avoid the requirement to provide electrical power into the pit working areas.

The mine operations schedule includes one 12-hour day shift, seven days per week for 365 days per year. Mine productivity and costing included estimating the productive shift operating time. Non-productive time includes shift change (travel time), equipment inspections, fueling, and operator breaks. SRK estimated that the total time per shift for these items will be 2.25 hours. The scheduled production time (scheduled operating hours) was therefore estimated at 9.75 hours per shift, representing a (shift) utilization of 81.3% of the 12-hour shift period (and excludes mechanical availability and work efficiency factors).

In addition, allowances were made for work efficiencies including equipment moves (production delays while moving to other mining areas within the pit), and certain dynamic operational inefficiencies. These work efficiencies are further discussed in the respective sections for loading and hauling.

Equipment fleet mechanical availability was estimated for the various major mine equipment fleets. Replacement equipment units for units that have reached their useful life are assumed to be new.

Table 13-8 shows the mining equipment fleet requirements for the mine plan.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 181

Table 13-8: Mining Equipment Requirements

Equipment Units	Model	Size		2023		2024		2025		2026		2027		2028		2029		2030		2031		2032		2033		2034		2035		2036		2037		2038		2039		2040		2041		2042		2043		2044		2045		2046		2047		2048		2049		2050		2051		2052		2053		2054		2055		2056
Loading
Wheel loader	WA600		8.4 yd3		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		1
Wheel loader	WA900		15.0 yd3		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		1		1		1		1		1		1		1		1		1		1		1
Hauling
Haul truck	775G		75 wst		1		1		2		2		2		2		1		2		2		2		1		2		2		2		2		2		2		2		2		3		2		2		2		1		1		1		1		1		1		1		1		1		1		1
Haul truck	HD785		102 wst		6		7		9		10		11		11		7		9		9		8		7		9		9		8		11		11		12		11		12		15		14		14		11		8		8		5		2		2		2		2		2		2		2		2
Other Mine Equip
Track dozer	D9		405 hp		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Motor grader	GD655		218 hp		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Motor grader	14M3		238 hp				1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Excavator	PC400		306 hp		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Water truck	775G		15,000 gal		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Water truck	HM400		8,000 gal		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Support Equip
Track dozer	D6		150 hp		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Wheel loader	WA600		8.4 yd3		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Haul truck	HM400		44 wst		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2
Fuel/Lube truck					1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
HD mech					1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Welding truck					1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Flatbed truck					1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1		1
Pumps / generators					1		2		2		2		2		2		3		3		3		3		3		4		4		4		4		4		4		4		4		4		4		4		4		4		4		4
Personnel bus					2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		1		1		1		1		1		1		1		1
Pickup trucks					7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		7		4		4		4		4		4		4		4		4
Light plant					6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		3		3		3		3		3		3		3		3

Source: SRK, 2023

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 182

13.6.2 Drilling and Blasting

MP Materials has contracted for drilling and blasting services. The contractor will provide all equipment, supplies, and labor to complete the services. It is MP Materials’ intention to continue with contractor drilling and blasting services for the foreseeable future. Accordingly, SRK has included a provision in the mining cost estimate for drilling and blasting services for the LoM timeframe.

Drilling is based on a 15 ft blasthole spacing and a 15 ft burden. The designed hole depth is 30 ft with a 4 ft subdrill. Dry blastholes will be loaded with ammonium nitrate fuel oil (ANFO). It is assumed that there will be 20% additional holes for pre-splitting, and 10% of blastholes will be loaded with emulsion (wet conditions).

The blasting contractor transports blasting accessories to site and stores these separately in a suitable explosives magazine. The blasting contractor has an explosives truck (ANFO/emulsion), which delivers bulk explosives to the open pit blast sites during daylight hours. Stemming material is ³⁄₄ inch rock. The blasting contractor manages and conducts the blasting operations.

13.6.3 Loading

The main loading equipment fleet for the mining operations is two Komatsu WA900 front-end loaders (15.0 yd³ bucket capacity). This equipment loads a fleet of six Komatsu HD785 haul trucks (102 wet st capacity).

The main loading equipment fleet for the mining operations will be assisted by two smaller front-end loaders (8.4 yd³ Komatsu WA600 units) and two Caterpillar 775 haul trucks (75 wet st capacity).

The dry density for waste was estimated to be 0.0864 st/ft³ (2.77 metric tonne/m³). The dry density for ore was estimated to be 0.0976 st/ft³ (3.13 metric tonne/m³). Rock moisture content was estimated to be 2% on average and swell in loading blasted rock to be 40%.

Table 13-9 shows selected loading statistics for the loading units when operating in waste.

Table 13-9: Loading Statistics by Unit Type in Waste

Equipment Type	Unit	Loader (Komatsu WA900)		Loader (Komatsu WA600)
Bucket Size	yd3		15.0		8.4
Matched Truck Rated Size	wet st		102		75
Number of Passes(1)	passes		4		6
Total Truck Loading Time	min		2.5		3.5
Moving and Delay Time	min/op hr		10		10
Waste Prod. Per Unit (100% Available)	dry short ton/op hr		1,986		1,052

Source: SRK, 2023

⁽¹⁾ Average 2% moisture assumed.

The total truck loading times included a truck spotting (initial positioning of the trucks for loading) time of 50 seconds.

Table 13-10 shows selected loading productivity information in waste for the planned loading equipment.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 183

Table 13-10: Loading Productivities by Unit Type in Waste

Equipment Type	Unit	Loader (Komatsu WA900)		Loader (Komatsu WA600)
Waste Prod. per Unit (100% Available)	dry t/op hr		1,986		1,052
Planned Operating Hours per Shift	scheduled op hrs		9.75		9.75
Planned Operating Hours per Year	scheduled op hrs		3,559		3,559
Estimated Mechanical Availability	op hrs %		85%		85%
Actual Operating Hours per Year	op hrs		3,025		3,025
Annual Waste Production Capacity per Unit	dry million st/yr		6.6		3.5

Source: SRK, 2023

As part of the mining operations, an allowance was made for re-handling crushed ore between the crusher and the mill with Komatsu WA900 loaders and HD785 haul trucks.

13.6.4 Hauling

Waste is hauled to the waste dumps. Ore is hauled to RoM stockpiles close to the primary crusher or, alternatively, to long-term stockpiles.

The main hauling equipment fleet for the pit mining operations is composed of 102 wet short ton capacity haul trucks (Komatsu HD785). The main fleet is supplemented with two Caterpillar 775G haul trucks (75 wet short ton capacity).

The Maptek Vulcan^™ haulage module was used to calculate the cycle times and distances. Routes were drawn from every bench for each pit phase to the destinations, and one-way distances reported.

Various haul profiles were developed for different time periods, and haulage cycle times from the pits were estimated for waste and ore. Base haul cycle times were estimated using the software, and these were factored for practical operational hauling aspects to reflect realistic cycle times.

Truck spot, load, and dump times were then added to the factored haul cycle times to make up total haul cycle times. Spot and loading times used were taken the loading unit time estimates.

Table 13-11 shows selected hauling productivity information for waste haulage.

Table 13-11: Hauling Statistics by Unit Type in Waste

Hauling Equipment Type	Unit	Komatsu HD785		Caterpillar 775
Rated Truck Size	wet st		102		75
Truck Fill Factor by Weight	Wet Tonnage Basis %		100%		100%
Typical Total Truck Loading Time (1)	min		2.50		3.50
Total Truck Dumping Time	min		1.20		1.20
Production per Unit (100% Available)	st/op hr		Variable based on haul profile		Variable based on haul profile

Source: SRK, 2023

⁽¹⁾ Includes truck spotting time; Komatsu HD785 loading with Komatsu WA900 and Cat 785G loading with Komatsu WA 600.

Table 13-12 summarizes the factored truck haulage cycle times from the pit for each year. These cycle times are the total truck cycle times and include truck spotting, loading and dumping times.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 184

Table 13-12: Pit Haulage Cycle Times (minutes)

Year	Waste		Ore
2023		15.1		22.9
2024		16.4		23.8
2025		20.0		23.9
2026		22.1		23.7
2027		23.7		24.2
2028		24.4		21.8
2029		12.4		21.3
2030		17.0		30.2
2031		17.8		27.6
2032		16.0		25.2
2033		13.4		23.0
2034		19.2		21.1
2035		17.4		24.0
2036		12.4		23.0
2037		17.9		28.2
2038		18.8		23.0
2039		18.8		24.6
2040		17.9		20.6
2041		19.4		28.8
2042		24.5		29.5
2043		22.9		21.8
2044		26.0		24.8
2045		29.3		28.6
2046		31.9		30.5
2047		34.2		32.4
2048		36.8		34.2

Source: SRK, 2023

Note: Total factored haul truck cycle times including loading, spotting and dumping.

Truck hauling productivities were calculated for each year of the mining operations and were used to estimate respective fleet hauling operating hours required, which were then used as the basis for determining the truck fleet requirements.

13.6.5 Auxiliary Equipment

Other major mining operations support equipment was previously shown in Table 13-8. The Caterpillar D9 track dozer is used for drill site preparation, road and ramp development, and maintenance of loading areas and waste dumps. The graders and water trucks maintain ramps, haul roads, and operating surfaces. The excavator performs site development work including pioneering and drainage diversion ditch development. The major mining equipment fleet size for roads and dumps is based on the general production level and allowance for general site conditions (including annual precipitation).

Annual operating hours were estimated for all of the major mining support equipment units, in general, between 1,512 and 3,025 operating hours per unit per year were scheduled for the mining operations.

The Caterpillar D6 track dozer is used for handling paste tailings. Other mining equipment involved in the handling of the paste tailings includes a Komatsu WA600 loader and two Komatsu HM400 articulated dump trucks (ADT) which will haul the paste to the tailings area for the dozer to then place.

Mining support equipment includes equipment maintenance units such as a fuel/lube truck, which delivers to equipment in the field from the fuel station, heavy duty mechanics’ truck, and welders’ truck.

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Page 185

Mine site operations and development utilize a flatbed truck, various moveable generators/pumps, light plants, transport van, and various service pickup trucks.

Dewatering is required for the pit. A combination of precipitation falling within the outer perimeter of the pit (normally only a few inches of rain per year) and groundwater inflows into the pit account for the total volume of water that is handled by the dewatering equipment.

13.6.6 Mining Operations and Maintenance Labor

The mine has salaried staff for mine administration, supervision of mine operations, supervision of mine equipment maintenance, and for technical services (geology and mining departments). These positions are on a permanent day shift. Operations employees fill mining production, mining support functions, and mining equipment maintenance positions.

The mine administration and operations supervision staff totals nine positions, and the technical services staff totals five positions. The total staff includes 14 positions. The operations, mine equipment maintenance, and technical services positions include:

• Mine administration includes a Senior Vice President Mining.

• Mine operations includes three shift foremen and two trainers/safety supervisors.

• Mobile maintenance includes a maintenance superintendent, a maintenance foreman and a maintenance planner.

• Mine geology includes a geologist and a senior geologist.

• Mine engineering includes a senior mine engineer, a mine planner and a surveyor.

Equipment operator labor positions are based on the number of mining equipment units required, and on the assumption that most of the operators are cross-trained (i.e., when operators are not required to be on one type of heavy equipment, they will be able to operate another type of equipment).

Operator positions are estimated for each year of operation. Required pit loading, hauling, and other support fleet equipment operators are based on the annual operating hours required. The operations assigned to the mining department also include the paste tailings loading and hauling, crusher feed loader, and loading and hauling crushed ore to the mill. Estimated annual labor costs include overtime allowances and burdens (33%).

A maintenance group is staffed with mobile equipment mechanics, electricians, welders, and other maintenance personnel.

The mining operations and maintenance labor requirements are shown in Table 13-13. The peak number of operations and maintenance personnel is 85, which occurs in 2042. The mine department staffing levels are reduced significantly during the later years of the mine life because pit mining concludes in 2048 and only stockpile rehandling occurs from 2049 through 2056.

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Table 13-13: Mining Operations and Maintenance Labor Requirements

Category	2023		2024		2025		2026		2027		2028		2029		2030		2031		2032		2033		2034		2035		2036		2037		2038		2039		2040		2041		2042		2043		2044		2045		2046		2047		2048		2049		2050		2051		2052		2053		2054		2055		2056
Loading Operators		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		6		4		4		4		4		4		4		4		4		4		4		4
Truck Drivers		14		16		22		24		26		26		16		22		22		20		16		22		22		20		26		26		28		26		28		36		32		32		26		18		18		12		6		6		6		6		6		6		6		6
Other Mine Equipment		9		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		10		9		9		9		9		9		9		9		9
Support Activities		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15		15
Total Mining Ops		44		47		53		55		57		57		47		53		53		51		47		53		53		51		57		57		59		57		59		67		63		63		57		47		47		41		34		34		34		34		34		34		34		34
Senior Mech/Elec		3		4		4		5		5		5		4		4		4		4		4		4		4		4		5		5		5		5		6		6		6		6		5		4		4		3		1		1		1		1		1		1		1		1
Mech/Elec		5		5		6		7		7		7		5		6		6		6		5		6		6		6		7		7		8		7		8		9		9		8		7		5		6		4		2		2		2		2		2		2		2		2
Assistant Mech		1		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		2		3		3		3		2		2		2		1		1		1		1		1		1		1		1		1
Total Maintenance		9		11		12		14		14		14		11		12		12		12		11		12		12		12		14		14		15		14		16		18		18		17		14		11		12		8		4		4		4		4		4		4		4		4
Total		53		58		65		69		71		71		58		65		65		63		58		65		65		63		71		71		74		71		75		85		81		80		71		58		59		49		38		38		38		38		38		38		38		38

Source: SRK, 2023

Note: Support activities include paste tailings loading and hauling, crusher feed loader, and loading and hauling crushed ore to the mill

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14 Processing and Recovery Methods

14.1 Historic Production

Over a 50-year operating history MP Material’s predecessor companies successfully produced bastnaesite flotation concentrates on a continuous basis for sale and/or further on-site processing. Table 14-1 presents the historic mill production from 1980 to 2002. During this period REO recovery ranged from about 52 to 69% from ore that that ranged from 7.18 to 9.47% TREO.

Table 14-1: Historic Mill Production, 1980 to 2002

Year	Milled (st)		Mill Feed Grade (TREO %)		REO Recovery (%)		Flotation Concentrate (lb TREO)
2002		183,487		7.91		67.0		2,616,000
2001		175,010		8.09		62.8		17,845,000
2000		No operation
1999		No operation
1998		321,000
1997		424,000		8.43		57.5		41,117,711
1996		544,000		--		--		42,513,000
1995		537,000		9.01		52.0		49,029,000
1994		508,000		8.68		56.4		49,726,403
1993		433,000		8.31		55.3		39,722,150
1992		409,000		8.80		60.4		42,800,327
1991		336,344		8.74		59.8		35,143,870
1990		480,161		8.81		60.2		50,943,008
1989		418,446		8.96		62.2		46,613,913
1988		221,764		9.74		60.5		26,135,080
1987		358,000		9.31		58.4		38,962,866
1986		225,000		9.47		57.3		24,414,453
1985		253,000		8.15		75.6		31,193,018
1984		543,354		7.82		68.9		58,176,586
1983		371,252		7.85		67.3		39,224,489
1982		391,417		7.30		69.0		38,581,897
1981		370,207		7.43		68.4		37,659,763
1980		360,068		7.18		68.2		35,243,503

Source: Mountain Pass Monthly Operational Reports, 1980 through 2002

14.2 Current Operations

MP Materials initiated the operation of a 2,000 t/d flotation concentrator during December 2017. The concentrator flowsheet includes crushing, grinding, rougher/scavenger flotation, cleaner flotation, concentrate thickening and filtration, and tailings thickening and filtration followed by dry stack tailings disposal. The generalized process flowsheet is shown in Figure 14-1, and each unit operation is briefly discussed in this section. Site infrastructure that supports the processing operations (e.g., power and water supply) is discussed in Section 15.

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Source: MP Materials, 2021

Figure 14-1: MP Materials Concentrator Flowsheet

14.2.1 Crushing

RoM ore is truck-hauled and stockpiled at the crusher in three separate stockpiles dependent upon grade. A front-end loader pulls from each stockpile as needed to achieve a target ore blend grade of approximately 8% to 9% TREO. The blended ore is crushed through a three-stage crushing circuit that includes a Svedala jaw crusher and two Terex cone crushers (MVP-380). Ore is crushed at the rate of 180 st per hour to produce a final -³/₈ inch crushed product that is stockpiled in multiple 20,000 st stockpiles.

14.2.2 Grinding

Crushed ore is truck-hauled to stockpiles beside the concentrator and then trammed with a front-end loader to the ore feed hopper from which it is conveyed to the grinding circuit. The grinding circuit consists of a 3.8 m diameter by 7.1 m EGL ball mill (2,500 horsepower (hp)), which is operated in a closed circuit with a cluster of Cavex-Weir cyclones to produce a final grind size of 80% passing (P₈₀) 45 microns (µm).

14.2.3 Reagent Conditioning and Flotation

The cyclone overflow from the grinding circuit is advanced to a four-stage conditioning circuit in which the required flotation reagents are sequentially conditioned at 135°F. The mineral collectors are added in the second and third conditioner. Froth modifiers are stage-added to the fourth conditioner. The conditioned slurry is then advanced to the rougher/ scavenger flotation circuit, which consists of two banks of tank cells. The resulting rougher/scavenger flotation concentrate is then advanced to multiple stages of cleaner/cleaner scavenger flotation. The final cleaner flotation concentrate is thickened to over 70% solids in a 35 ft diameter thickener and then filtered to about 8% moisture in a 1,500 mm x 1,500 mm 20/16 Siemens filter press. The filtered concentrate is hauled to a storage area pending

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sampling and bagging for shipment. The rougher and cleaner scavenger flotation tailings are combined as the final concentrator tailing, which is pumped to the paste tailings plant where it is filtered to about 15% moisture and then truck-hauled to the northwest tailing disposal facility (NWTDF).

14.2.4 Sampling and Bagging

The bastnaesite flotation concentrate is manually loaded into 1.5-tonne Super Sacks with a small front-end loader. Each loader bucket of concentrate is sampled multiple times with a pole sampler prior to being added to the Super Sack, and a sample representing the contents of each Super Sack is sent to the analytical laboratory for analyses and moisture content determination. Each Super Sack is weighed with a scale as it is being loaded, and the final weight of each Super Sack is recorded. Concentrate is shipped from site in containers, and each container contains 13 Super Sacks.

14.2.5 Paste Tailings Plant

Concentrator tailings are pumped to the paste plant, which is remotely located near the dry stack NWTDF. At the paste tailings plant, the concentrator tailings are thickened to about 65% solids and then filtered in three fully automatic filter presses (Siemens 1,500 mm x 2,000 mm 60/50) to about 15% moisture. In order to achieve a clear thickener overflow, a coagulant is added, followed by the addition of a slightly anionic flocculant at the thickener mix box. Tailings are conveyed to a stockpile outside the paste tailings plant and then hauled to the NWTDF, which is discussed in Section 15.

14.2.6 Metallurgical Control and Accounting

Ore feed tonnage to the concentrator is obtained from a belt scale on the ball mill feed conveyor, and operational performance of the concentrator is monitored by manually sampling the feed, final flotation concentrate, and final tailings every two hours, which are then prepared and analyzed by x-ray fluorescence (XRF) for %TREO. This information is used to monitor the concentrator performance and to make any required adjustments to the process. This information is also used to calculate a metallurgical TREO recovery and metric tonnes of bastnaesite flotation concentrate produced.

Final flotation concentrate production is weighed and sampled as it is being loaded into 1.5 tonne Super Sacks for shipment, and a concentrate sample representing each shipment lot is assayed at the on-site laboratory using a total digestion/titration technique to determine %CeO₂ content. Based on experience, MP Materials has determined that bastnaesite at Mountain Pass contains approximately 50% CeO₂, and from this they are able to calculate the total %TREO content of the concentrate. There is reasonable agreement between the metallurgical TREO recovery reported by the concentrator (which is determined by XRF analyses of concentrator samples) and packaged recovery (which is determined by actual shipments of TREO concentrate).

14.2.7 Concentrator Performance

Concentrator performance for 2022 is summarized in Table 14-2, and concentrator performance for 2023 (January – September) is summarized in Table 14-3. During 2022, the concentrator processed 782,985 metric tonnes (mt) of ore at an average grade of 8.5% TREO and produced 74,859 mt of bastnaesite concentrate at an average grade of 61.3% TREO. Overall TREO recovery averaged 65.3%. During Q4 2022, 276 t of TREO was roasted to provide feed to the new separations plant as part of initial plant commissioning activities. During 2023 (January to September), the concentrator processed 601,107 mt of ore at an average grade of 8.6% TREO and produced 56,552 mt of bastnaesite

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concentrate at an average grade of 61.9% TREO. Overall TREO recovery during 2023 (January to September) has averaged 64.0%. During 2023 (January – September) 10,859 mt of TREO was roasted to support commissioning activities at the new separations plant. Roasted TREO was either bagged and shipped directly along with unroasted concentrate or advanced to the separation plant leach circuit.

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Table 14-2: Concentrator Production Summary - 2022

Period	Feed						Concentrate						TREO to Concentrate				TREO Tonnes
	Tonnes		TREO (%)		TREO Tonnes		Tonnes		Moisture (%)		TREO (%)		Tonnes		Recovery (%)		Unroasted		Roasted
Q1		187,533		8.67		15,934		19,149		8.0		61.5		10,829		68.0		10,829
Q2		192,673		8.42		15,851		18,192		7.6		61.3		10,295		64.9		10,295
Q3		206,577		8.34		16,851		19,305		8.1		61.3		10,877		64.5		10,877
Q4 (1)		196,202		8.54		16,393		18,213		8.4		61.2		10,486		64.0		10,210		276
Total		782,985		8.49		65,029		74,859		8.0		61.3		42,487		65.3		42,211		276

Source: MP Materials, 2023

Note: Q4 TREO production includes 276 t that was roasted as feed to the separation plant.

Table 14-3: Concentrator Production Summary - 2023 (Jan-Sep)

Period	Feed						Concentrate						TREO to Concentrate				TREO Tonnes (1)
	Tonnes		TREO (%)		TREO Tonnes		Tonnes		Moisture (%)		TREO (%)		Tonnes		Recovery (%)		Unroasted		Roasted
Q1		198,044		8.61		16,663		18,629		7.6		62.0		10,671		64.0		7,674		2,997
Q2		196,515		8.71		16,766		19,097		8.0		61.8		10,862		64.8		7,342		3,520
Q3		206,548		8.41		17,019		18,826		7.7		61.9		10,766		63.3		6,423		4,342
Total		601,107		8.57		50,448		56,552		7.7		61.9		32,299		64.0		21,439		10,859

Source: MP Materials, 2023

⁽¹⁾ A portion of flotation concentrate production was roasted, and a portion of the roasted concentrate was advanced to the separation plant leach circuit.

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14.2.8 Significant Factors

The following significant factors for the crushing and concentrating operations have been identified:

• MP Materials conducted flotation studies to evaluate TREO recovery versus ore grade and developed a mathematical relationship to estimate overall TREO recovery versus ore grade. This relationship has been used to estimate TREO recovery from lower grade ores later in the mine life.

• MP Materials has operated a flotation concentrator since December 2017 to recover a bastnaesite concentrate. Significant improvements in concentrator performance have occurred since inception of operations, which are attributed primarily to the installation of a boiler that has enabled flotation to be conducted at a constant higher temperature, as well as new reagent testing and blending of historically problematic ores.

• During 2022 TREO recovery averaged 65.3% into concentrates containing an average of 61.3% TREO.

• During 2023 (January - September) TREO recovery has averaged 64.0% into concentrates averaging 61.9% TREO.

• MP Materials has constructed a new separations plant to further process bastnaesite concentrate into separate rare earth products. The new separations plant is currently in commissioning and is expected to ramp-up to full production capacity by the end of 2024.

14.3 Individual Rare Earth Separations

The discussion in Section 14.3 has been prepared by SGS. MP Materials has determined that SGS meets the qualifications specified under the definition of qualified person in 17 CFR § 229.1300.

MP Materials plans to produce four main products initially: PrNd oxide, lanthanum carbonate, cerium chloride, and an SEG+ concentrate. The specifications are as shown in Table 14-4.

Table 14-4: Product Specifications

Product	Compound	w/w % TREO	Purity
PrNd Oxide	75% Nd2O3 + 25% Pr6O11 (+/-2%)	99%	99.5%+ PrNd/TREO
SEG+ Oxalate/Concentrate	-	25% to 45%	99% SEG+/TREO
Lanthanum Carbonate	La2(CO3)3 + La2O3	99%	99% La/TREO
Cerium Chloride	LaCeCl3	45%	85% Ce/TREO

Source: MP Materials, 2021

Note: w/w % is the weight concentration of the solution.

The current rare earth concentrate production of approximately 42,700 metric tonnes of TREO in the twelve months trailing September 2023 supports this plan.

To achieve the individual production and purity targets, the process flow will combine traditional processing methods applied successfully at Mountain Pass for decades with unique circuits designed for efficiency or to reduce environmental impact.

Figure 14-2 serves as the basis for the rare earth distribution in the concentrate being fed into the downstream separations facilities. These values are based on recent concentrate production and historical values. The rare earth distribution in the ore coming out of the mine, and the resulting concentrate produced from milling & flotation, has been very consistent throughout the decades of operations at Mountain Pass. These values fall within recently and historically reported values.

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Flotation Concentrate - REO Distribution
Lanthanum	32.3%
Cerium	50.2%
Praseodymium+Neodymium	15.7%
SEG+	1.8%

Source: MP Materials, 2021

Figure 14-2: Rare Earth Distribution in Flotation Concentrate

Concentrate Thickening & Filtration: The Stage 2 optimization will install a new like-in-kind filter press and ancillary equipment. This modification is being added primarily for material handling considerations rather than for technical ones. The existing filter press – from which the new press is designed – is currently in successful operation. However, the handling of semi-damp filter cake on a batch basis into the dryer was expected to have created a challenge in its existing location. Hence a redundant press was designed to minimize conveyance risks.

Concentrate Drying & Calcining: The direct-fire natural gas dryer was designed to manage the batch flow of concentrate from the filter press. The function of low temperature drying is to reduce the cake moisture from 7% to 10% down to less than 1%. This dried material will feed a storage bin that will continuously feed the electric fired calciner. The multiple, electric heating elements are designed to maximize temperature control and stability throughout the rotary kiln so that the targeted LOI (loss on ignition) is achieved in the concentrate prior to leaching. The discharge of the calciner will include a cooling screw and storage and cooling tanks with up to two days of capacity. There will also be the ability to automatically package calcined concentrate.

Leach and Scrubber: The concentrate will be pneumatically conveyed into a dissolution tank where it will be cooled to ambient temperature in chilled water. Temperature will be maintained by application of a glycol chiller system. The concentrate will be continuously fed into the existing Leach 2.0 reactor tanks where HCl will be added at different concentrations to maximize trivalent REO recovery and cerium rejection. Temperature will be maintained by the chiller and heat exchangers. The additional mass flow as compared to the predecessor system and the insolubility of the cerium results in the production of chlorine gas that will be scrubbed using the new, larger scrubber system combined with an existing venturi system.

Leach Thickening & Filtration: A new three stage countercurrent decantation tank system will be installed. This installation mirrors the leaching process from the 1970’s. The countercurrent motion of overflow and underflow and multiple flocculent addition points are designed to ensure clean overflow and minimal loss of soluble REEs to the underflow. The final underflow slurry will pass through a filter press. The cake will then be washed to remove remaining rare earth chloride solution and then either packaged for sale or reslurried and comingled with beneficiation tailings for disposal.

Impurity Removal: Removal of soluble impurities begins in this block that is being recommissioned with minimal change Initially, the solution will pass through three existing ion exchange columns containing a standard resin. Substantially all iron and uranium will be removed and sent to the brine recovery circuit. The solution will then undergo pH adjustment to remove certain non-REE impurities. The solid will precipitate in a new thickener to replace temporary assets previously operated. A filter aid

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will be added from a new bulk handling system. This addition will increase the propensity to settle and enhance the ease of filtration. To capture all fine solids as well as minimize the production of hazardous waste, a new pressure leaf filter will be installed prior to existing cartridge filters. The new filter press will be installed in place of previously operated temporary filter presses. In the next step, REE will be separated from the remaining impurities. The waste will be sent to brine recovery and the high-concentrate REE feed will go to SXH.

Brine Purification: Brine feeds from impurity removal stages, various finished product solid/liquid separation steps, and water treatment plant will converge at the existing brine purification circuit. Two existing thickeners will be operated with soda ash, flocculant, and caustic soda to adjust pH and maximize settling of impurities. A second filter press, relocated from another use at Mountain Pass, will be installed to help balance the filtration needs. A new pressure leaf filter will be installed to assist in removal of any fines from the filtrate feeding the crystallizer, to which the clean brine will be sent.

SXH: The purified rare earths will be pumped to the existing SXH circuit. SXH is a series of small mixer/settlers utilized to perform a bulk extraction of heavy rare earths (from samarium and heavier) from the light rare earths (La, Ce, Pr, Nd). Minor upgrades are planned to the existing assets to increase automation control. The cleaner feed stream supplying SXH is expected to ensure a cleaner separation between Nd and Sm.

SEG+ Finishing: The pregnant solution from SXH will contain the SEG+ chloride solution. This will be sent to the existing finishing circuit in the “Specialty Plant.” An oxalic solution will be added to the SEG+ chloride solution to produce SEG+ oxalate. The oxalate will be maintained in an agitated tank before passing through a centrifuge. The thick slurry will then be washed, dried, and packaged in recommissioned, existing assets. The mother liquor will be returned to the leach circuit as low acid solution or sent to brine purification for neutralization.

SXD: The raffinate from SXH will travel to the existing SXD circuit. The custom-designed mixer/settlers will ensure clean separation between PrNd and La and the remaining Ce. Certain additions are being made to allow for the subsequent production of high-purity (greater than 99.5%) lanthanum product and a greater than 80% Ce (20% La) cerium chloride product to be produced. The cerium product solution will be directly packaged from this circuit. No additional changes are planned.

PrNd Finishing: The PrNd finishing circuit is being constructed to ensure maximum on-specification production of PrNd oxide. No new technology is being implemented, but redundance and enhanced quality control capability are included in the design. The initial step will be the precipitation reactors. The new reagent handling system will produce the precipitant solution which will mix with the PrNd chloride solution. This mixture then feeds a new 2-tank CCD thickener to ensure maximum PrNd recovery with maximum disentrainment of chloride from rare earths. The rare earth underflow will feed a belt filter equipped with multiple washing steps to remove remaining chlorides. The cake will then be repulped in RO water and fed to a new filter press. The filter cake will feed a new gas-fired rotary dryer. The dry product will be pneumatically conveyed into a new rotary calciner to produce the oxide. Finally, the cooled oxide will be automatically packaged. At each step there will be QA/QC tanks, hold points, and automatic blending capability. Between the dyer and the calciner will be a large rotary mixer to allow for blended “batches” to be thoroughly mixed to meet specifications.

La Finishing: The La finishing circuit will start with the lanthanum chloride from the SXD ancillary strip section. This solution will be pumped to the existing precipitation tanks in the specialty plant. Here soda ash solution from the central tank farm’s new soda ash system will be mixed to produce a lanthanum

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carbonate precipitate. This solution will be pumped to the new 2-tank CCD thickener system to remove the lanthanum carbonate in the underflow while minimizing REE loss to the overflow. The carbonate will undergo the same belt filter, repulp, filter press steps as the PrNd, using identical assets. The filter cake will be fed to a new rotary dryer. The dry carbonate can be packaged directly. A minority of customers may prefer lanthanum oxide over lanthanum carbonate, so a new pneumatic conveyance line will be installed to transport the dry carbonate to the existing lanthanum calciner. The existing feed system is being modified to account for the improved handling conditions (dry carbonate vs wet cake).

Brine Evaporation: The clean brine from the brine purification process will feed the existing brine evaporation system. This process is being upgraded to manage the new service to feed the crystallizer (rather than chlor-alkali installation). The four heat effects will concentrate the brine to 300 g/L NaCl from approximately 100 g/L NaCl, thereby maximizing the crystallizer capacity.

Salt Crystallizing: A thermal vapor recompression (TVR) crystallizer is being installed to evaporate the high-concentration brine, remove the salt, and condense the high-purity water for re-use. The unit is designed to operate using the excess steam from the combined heat and power plant (CHP), thereby reducing the energy footprint.

Water Softening / RO Water Treatment: The existing Water Treatment Plant (WTP) was in operation from 2012-2015 and was recommissioned in fall 2021. It has the capability to make triple-pass RO water from potable water, with the retentate discharge being sent to brine recovery. RO water from this plant can be used to feed the leach, SX, product finishing, and CHP requirements. It is expected that once the crystallizer is operational, condensate from the crystallizer and CHP will provide the vast majority (possibly more than 100%) of pure water needs, resulting in minimal use of the WTP.

CHP: the CHP operated safely and reliably from 2012-2015. It has undergone a large recommissioning effort overseen by a specialty power plant recommissioning group. As of fall 2023 it has been in full operation in island mode over the last several years. In addition, a new load bank, back-up generator, and dump condenser were installed and commissioned. The plant was put into full service at the end of 2021. The two single-cycle generators with heat recovery steam generators (HRSG) are each capable of producing 12-13MW. The two turbines in operation will more than adequately cover the power needs of the site while producing sufficient steam for the crystallizer, flotation plant, and various other heating needs across the facility.

Stage 2 Related Infrastructure: In addition to the captive power and water treatment plant, general site services include a centralized bulk reagent tank farm with storage for HCl and NaOH. Bulk handling for soda ash and other reagents are being buttressed as part of the Stage 2 project.

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15 Infrastructure

The Project is in San Bernardino County, California, north of and adjacent to Interstate 15 (I-15), approximately 15 mi southwest of the California-Nevada state line and 30 mi northeast of Baker, California (Figure 3-2).

The nearest major city is Las Vegas, Nevada, located 50 mi to the northeast on I-15. The Project lies immediately north of I-15 at Mountain Pass and is accessed by the Bailey Road Exit (Exit 281 of I-15), which leads directly to the main gate. The mine is approximately 15 mi southwest of the California-Nevada state line in an otherwise undeveloped area, enclosed by surrounding natural topographic features.

Outside services include industrial maintenance contractors, equipment suppliers and general service contractors. Access to qualified contractors and suppliers is excellent due to the proximity of population centers such as Las Vegas, Nevada as well as Elko, Nevada (an established large mining district) and Phoenix, Arizona (servicing the copper mining industry).

Access to the site, as well as site haul roads and other minor roads are fully developed and controlled by MP Materials. There is no public access through the Project area. All public access roads that lead to the Project are gated at the property boundary.

MP Materials has fully developed an operating infrastructure for the Project in support of extraction and concentrating activities. A manned security gate is located on Bailey Road for providing required site-specific safety briefings and monitoring personnel entry and exit to the Project.

Substantially all the power to the Mountain Pass facility is currently supplied by a Combined Heat and Power (CHP) or co-generation (cogen) power facility with two natural gas-fired turbines capable of producing up to 26 MW of power combined. In addition, the site is served by a 12-kV line from a Southern California Edison substation two miles away.

Water is supplied through active water wells located eight miles west of the project. Fire systems are supplied by separate fire water tanks and pumps.

The site has all facilities required for operation, including the open pit, concentrator, access and haul roads, explosives storage, fuel tanks and fueling systems, warehouse, security guard house and perimeter fencing, tailings filter plant, tailings storage area, waste rock storage area, administrative and office buildings, surface water control systems, evaporation ponds, miscellaneous shops, truck shop, laboratory, multiple laydown areas, power supply, water supply, waste handling bins and temporary storage locations, and a fully developed communications system.

Site logistics are straightforward with the flotation concentrates shipped in supersacks within a shipping container. The shipping containers are hauled by truck to the port of Los Angeles, which is about 4.5 hours from the mine site. At the port the containers are loaded onto a container ship and shipped to the final customers. Refined products for domestic customers are shipped in supersacks and intermediate bulk containers (IBC tote). Rail transshipment infrastructure are available in Henderson, NV and Barstow, CA less than 2 hours drive from the site.

15.1 Access and Local Communities

The Project is located in San Bernardino County, California, north of and adjacent to Interstate 15 (I-15), approximately 15 mi southwest of the California-Nevada state line and 30 mi northeast of Baker,

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California. The site is accessed via I-15 and leaving the highway at exit 281 onto Bailey Road north of the interstate for less than 1 mile.

The majority of the employees live in Las Vegas, Nevada 50 miles northeast of the site via I-15. Las Vegas is a major metropolitan area with approximately 650,000 people in the city and 2.2 million in the metropolitan area. Major services to support the Project including vendors, contractors, and services are available in Las Vegas as well as approximately four hours southwest in the Los Angeles (LA), California metropolitan area. Baker California, population of approximately 700, is the next nearest town 37 mi southwest along highway toward LA on I-15.

Air access to the Project is provided at McCarran International Airport located approximately 47 mi northeast of the project in south Las Vegas. Other airports are available in the Los Angeles area.

Employees drive or carpool to work and park in the company parking lots on site. Full emergency facilities are available in Las Vegas with emergency dispatch in Primm, NV and Baker, CA.

15.2 Site Facilities and Infrastructure

15.2.1 On-Site Facilities

The Project has fully developed operating facilities and facilities necessary to support the current operations. The general layout of the facilities is shown in Figure 15-1.

Source: MP Materials, 2022

Figure 15-1: Facilities General Location

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The currently operating facilities include:

• Maintenance shop

• Truck shop

• Warehouse

• Administrative building/offices

• Change house

• Explosives storage

• Electrical shop

• Fuel storage tanks and fueling system

• Multiple laydown areas

• Core storage

• Water evaporation ponds

• Mineral processing facilities (concentrator)

• REE separations facility

• Laboratory

• Fuel storage

• Fire system including fire tank and pumps

• Water supply system

• Tire repair area

• Tailings filter plant

• Lined tailings storage facilities

• Waste rock storage

• Security building and site fencing

The LoM plan will require the relocation in 2035 of the paste tailings plant and the water tanks currently northeast of the pit highwall near the concentration plant. Additionally, the crusher will be relocated in 2028 to allow the pit to expand to the north. Capital cost provisions are included in the economic model for these relocations.

15.2.2 Explosives Storage and Handling Facilities

The site has two explosives storage locations. Contractors manage the ANFO storage and emulsion storage locations.

15.2.3 Service Roads

The Project has a completely developed system of on-site access roads to all process facilities, tailings storage area, and a system of auxiliary roads for the mining, processing and on-site operations.

15.2.4 Mine Operations and Support Facilities

The open pit mine has a full complement of haul roads, ramps, and auxiliary roads with access to the pit, waste storage area, shops, and crusher area.

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15.2.5 Waste and Waste Handling (Non-Tailings/Waste Rock)

The Project has established waste handling procedures and does not store waste on site, except for the permitted rock storage and tailings facilities. Waste other than tailings and mine waste rock is handled as follows.

• Solid Waste (non-toxic) – Waste is stored on-site in roll off containers, and a contractor hauls the containers to permitted third party landfills near Las Vegas.

• Septic – The site has septic systems for the facilities.

• Toxic or hazardous waste – Very little hazardous or toxic waste is generated at the Project. The small volumes of materials have a separate storage area. The materials are removed by a qualified contractor and disposed of in approved disposal areas.

15.2.6 Waste Rock Handling

Mine waste rock is stored in designated mine rock storage areas. Waste rock is discussed in detail in Section 13.

15.2.7 Power Supply and Distribution

Substantially all the power to the Mountain Pass facility is currently supplied by a Combined Heat and Power (CHP) or co-generation (cogen) power facility with two natural gas-fired turbines capable of producing up to 26 MW of power combined. In addition, the site is served by a 12-kV line from a Southern California Edison substation two miles away.

15.2.8 Natural Gas

The Project has access to natural gas through an 8.6 mi, 8-inch-diameter pipeline, extending from the Kern River Gas Transmission Company mainline. It has a capacity of 24,270 dekatherms per day. A new gas meter was installed in 2021 to provide flexibility for high and low gas usage.

15.2.9 Vehicle and Heavy Equipment Fuel

The site has multiple fuel storage tanks and fuel delivery systems for the large mining equipment and smaller vehicles. Fuel for the mining equipment is supplied through the mining contractor who receives the fuel from a vendor located in Las Vegas. MP Materials can contract the fuel directly in the future. There are tanks for diesel near the pit and near the processing facility. Additional tanks are used for unleaded fuel for the vehicles.

The site has several diesel and gasoline storage tanks that are for Project use. The tanks are fueled by contractor fuel trucks from Las Vegas. Tank storage is more than adequate for the Project needs.

15.2.10  Other Energy

There are several compressed air systems on the site used for process and maintenance. The site also has several small propane tanks used for miscellaneous minor heating needs at the various facilities.

15.2.11  Water Supply

MP Materials maintains and operates two water supply well fields for potable and process water. The Ivanpah well field, established in 1952, is located on private land 8 mi east of the mine site and consists

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of six freshwater producing wells, three booster pumping stations, and associated pipelines. This well field is available to supply water but is currently used only to provide water to the Mojave National Preserve Ivanpah Desert Tortoise Research Facility. The Shadow Valley well field, established in 1980, is located 8 mi west of the mine site, consists of four wells of which three are on public land and one on private land, a single booster pumping station, and associated pipelines. The water supply wells are completed within coarse alluvial sediments.

The amount of freshwater consumed by the facility in 1996 was approximately 850 gpm from both wellfields. The five-year annual average between 1993 and 1997 was 795 gpm. As part of the comprehensive plan for continued operations, MP Materials placed emphasis on-site management and treatment of process water and maximizing reuse (SRK, 2010). As the water supply systems have consistently produced much larger amounts of fresh water for the facility in the past, water supply is not anticipated to be problematic.

Additional water is supplied from recovery well water from legacy operations, pit water, and natural precipitation. The site also has water storage tanks that store water for use as needed on site. The site has a net-positive site water balance with excess water evaporated as necessary in the evaporation ponds. The water supply system can be seen in Figure 15-2.

Source: Molycorp Mine Reclamation Plan Revised, 2015

Figure 15-2: Water Supply System

The site has installed surface water control drainage channels and ponds, including lined evaporation ponds and a lined tailings water control pond.

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15.3 Tailings Management Area

The Project handles tailings through use of a filtered tailings facility located adjacent to the pit to the north and west of the primary crushing facility and northwest of the existing open pit adjacent to the pit to the northwest and east of the overburden stockpile. The Project manages tailings through use of a filtered tailings facility that produces filtered tailings. The concentrator generates tailings that are piped to the filter plant via pipeline. The filtered tailings plant then filters the tailings to approximately 15% moisture content. The filtered tailings are moved on a conveyor to a temporary storage facility where the tailings are stacked out near the tailings plant and then loaded by front end loader (FEL) into articulated mine trucks that transport the tailings approximately 1 mile to the lined tailings facility known as the Northwest Tailings Disposal Facility (NWTDF). After the material is dumped by the trucks, a small dozer levels the tailings and prepares the material for the next truck lift.

The NWTDF is a lined containment facility that is designed to receive and store tailings material. The NWTDF at full buildout will eventually cover approximately 90 acres (36 hectares) and about the north face of the west overburden stockpile. The design capacity of the NWTDF is approximately 24 million st. The project has utilized approximately 4.2 million st of that space as of September 30, 2023. The facility will have a remaining capacity of approximately 19.8 million st which will provide approximately 24 years of storage. The current facility covers about half the overall acreage and abuts the waste rock pile. Expansion is straightforward in the future with the addition of liner and then placement of the additional tailings. The facility design at full buildout is shown in Figure 15-3.

Source: Molycorp Mine Reclamation Plan Revised, 2015

Figure 15-3: Northwest Tailings Disposal Facility

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The tailings site was designed by Golder. MP Materials personnel have been doing design and placement reviews with Golder. There is compaction information being taken, but the program at this point is not fully developed.

MP Materials will expand the existing tailings facility to the northwest in approximately 2047 to provide an additional 9 years of storage capacity. A capital cost provision has been included in the economic model for this expansion.

15.4 Security

The site is controlled in its entirety by fencing with a security building and controlled access through the main gate. MP contracts with a security firm to staff the main gate and provide roving services around the perimeter of the site.

The site is fully fenced and has a restricted entry through a guard gate and building at the main entrance.

15.5 Communications

The site communications are fully developed and functioning, including a fiber line to site. Additionally, a strong cell phone signal is available due to placement of a third-party cell phone tower on a peak near the site. The site has telephone, internet, and all necessary infrastructure to support needed communications.

15.6 Logistics Requirements and Off-Site Infrastructure

15.6.1 Rail

Rail is not currently used by the Project. Union Pacific has a rail line located approximately 16 miles away by paved road to the east of the Project near Nipton, California. There are existing double track sections near the Nipton warehouse and loading platforms are still in place but have not been used or maintained.

15.6.2 Port and Logistics

It is approximately 230 miles southwest of the Project to the Port of Los Angeles. The 4.5 hour drive is on improved two and four lane highway with the majority of the trip by Interstate highway. The travel closer to LA is impacted by traffic. Site logistics are straightforward with the concentrate product shipped in supersacks within a shipping container by truck to the port of Los Angeles. At the port, the containers are loaded onto a container ship and shipped to the final customers. Refined products for domestic customers are shipped in supersacks and intermediate bulk containers (IBC tote).

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16 Market Studies and Contracts

This section of the Technical Report Summary discusses market studies and contracts and was prepared by Adamas Intelligence Inc. (Adamas). It is primarily based on an Adamas authored preliminary market study titled “MP Materials SK 1300 Market Study Update” dated October 16, 2023 (Adamas, 2023). Adamas prepared the preliminary market study for MP Materials. MP Materials has determined that Adamas meets the qualifications specified under the definition of qualified person in 17 CFR § 229.1300.

16.1 Abbreviations

The following abbreviations apply to the discussion of market studies and contracts.

Table 16-1: Abbreviations for Market Studies and Contracts

Elements	Organizations
Ce - Cerium	MIIT - Ministry of Industry and Information Technology (China)
Dy - Dysprosium	MOFCOM - Ministery of Commerce (China)
Er - Erbium	USEPA - United Stated Environmental Protection Agency
Eu - Europium	WTO - World Trade Organisation
Gd - Gadolinium	Other
Ho - Holmium	CAGR - compound annual growth rate
La - Lanthanum	NdFeB - neodymium iron boron
Lu - Lutetium	NdPr - neodymium/Praseodymium mixed product
Nd - Neodymium	OEM - original equipment manufacturer
Pr - Praseodymium	TC/RC - treatment charge/refining charge
Sc - Scandium	VAT - value added tax
Sm - Samarium	EV - electric vehicle
Tb - Terbium	Units and Measurements
Th - Thorium	kg - kilogram
Tm - Thulium	t - metric tonne
Y - Yttrium	kt - thousand tonnes
Yb - Ytterbium	Mgal - million gallons
U - Uranium	Mgal/d - million gallons per day
Rare earth element abbreviations	$ - USD dollars (unless stated otherwise )
REE - rare earth element
LREE - light rare earth element
HREE - heavy rare earth element
REO - rare earth oxide
TREO - total rare earth oxide
SEG - samarium europium gadolinium

Source: Adamas, 2023

16.2 Introduction

On the Periodic Table of Elements, rare earth elements (REEs) include the lanthanide series, with atomic numbers 57 to 71, plus yttrium and scandium, which bear similar physical and chemical properties to the lanthanides and thus are often hosted by many of the same minerals.

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Despite the misleading moniker, rare earth elements are not remarkably rare in nature but rather are rarely concentrated into economically significant amounts for extraction and processing owing to certain physical and chemical properties that promotes their broad dissipation throughout most rock types.

REEs occur together in host minerals in different relative proportions, depending on the host mineral, deposit type and other factors. As a result, REEs are mined and processed together, up to the stage of REE precipitate production (e.g., mixed rare earth carbonate). They are then chemically separated into individual elements and compounds for use in a wide array of different industries and applications. For example, the main REEs used in rare earth permanent magnets are neodymium (Nd) and praseodymium (Pr), while the main elements used in catalysts are cerium (Ce) and lanthanum (La).

Owing to these different end use profiles, individual rare earth elements have different demand growth rates, but are supplied in proportions dictated by orebody composition, giving rise to the so-called “balance problem”.

Over the past decade, rare earth producers globally have sacrificially overproduced certain low value rare earth elements, such as cerium, to keep up with rapidly growing demand for other higher value elements, such as neodymium and praseodymium. This balance problem fundamentally shapes rare earth market trends and impacts the economics of producers.

Since the mid-1980s, China has grown to become the largest producer and consumer of rare earth elements globally. In the 1980s and 1990s, China accelerated exports of low-priced rare earth materials resulting in the economic displacement of production elsewhere. More recently, China has leveraged its control of upstream REE supply, coupled with aggressive policies and government support, to establish control of downstream REE value chains that convert mine outputs into oxides, metals, magnets, motors and more.

However, rapid global demand growth for rare earth permanent magnets for electric vehicles, wind power generators and other applications, combined with strong government support for development of alternative rare earth supply chains, indicate that China’s dominance is likely to erode over the coming decade.

Towards that end, the past 12 months have seen more momentum to establish alternative mine-to-magnet supply chains in North America and Europe than the past 12 years combined. With the ongoing diversification of upstream REE supplies, much of the chicken-and-egg dilemma of yesteryear has been resolved, helping accelerate downstream investments in North American and European metals, alloy and magnet production capacity.

Below, Adamas provides considerations on the rare earth market in terms of the products presently produced and to be produced in the future by MP Materials’ Mountain Pass Rare Earth Mine and Processing Facility.

Based on expected product specifications as discussed by SGS in Sections 10.4.5 and 14.3 of this Technical Report Summary, which appear reasonably achievable, MP Materials will likely be able to market products at forecasted prices. These product specifications are based on the opinion of MP Materials and SGS, which are in turn based on test work and prior operations using the existing infrastructure as well as initial production runs from MP’s recently recommissioned facility.

All prices shown and discussed below are in REO terms, unless stated otherwise.

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16.3 General Market Outlook

16.3.1 Historical Pricing

Historically, rare earth prices have occasionally been tied to geopolitical events.

For example, on September 7, 2010, a Chinese fishing trawler operating in disputed waters near the Senkaku/Diayu Islands collided with one or more Japanese Coast Guard patrol boats, resulting in the detention of the trawler’s skipper. The detention sparked a major diplomatic dispute between China and Japan, leading China to unofficially restrict and eventually halt rare earth element exports to Japan, its largest customer, for several months. Consequentially, global rare earth prices, controlled by China, soared to record levels in 2011 resulting in unprecedented cost increases for rare earth consumers worldwide.

Starting in the early-2000s, China’s Ministry of Industry and Information Technology (MIIT) began imposing export restrictions that over time limited the amount of rare earths available to foreign manufacturers. At the same time, China imposed export duties on refined rare earth products and implemented tax policies to limit the volume of semi-processed rare earths leaving the country with the aim of luring foreign manufacturers (such as NdFeB magnet producers) to move their operations and/or transfer their technology to China.

These practices prompted the U.S., EU and Japan to initiate a WTO dispute in 2012, which ruled in their favor in 2015, leading to the abolishment of China’s rare earth export quotas and duties.

Annual PrNd oxide price volatility is shown in Figure 16-1.

Source: Adamas, 2023

Figure 16-1: Annual PrNd Oxide Price Volatility

In the second half of 2010, China’s Ministry of Commerce (MOFCOM) slashed the export quota allotted to domestic rare earth suppliers, effectively limiting the amount of material available for consumption outside of the nation. As of August 2010, the constrained availability of rare earth elements for export in China had already begun to propel prices higher. The subsequent Senkaku/Diayu Islands incident

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the following month exacerbated the market’s concerns and fueled a buying frenzy into mid-2011 that pushed rare earth prices to record high levels.

From January 2010 through July 2011, the China export price of cerium oxide increased by 3,528% while that of lanthanum oxide, neodymium oxide, praseodymium oxide and yttrium oxide increased by 2,619%, 1,640%, 1,167% and 1,341%, respectively, over the same period.

The political dispute was resolved soon after prices spiked, leading most rare earth prices to fall back to historical normal levels in the ensuing 24 months. In the aftermath, global supply and demand contracted, the latter the result of demand destruction as rattled manufacturers outside of China looked to reduce the mass of rare earths used in their products.

Since that period, demand for PrNd oxide – the main rare earth input material for high strength permanent magnets – has returned to strong year-over-year growth on the back of electric vehicle traction motors, wind power generators, industrial robots and more. In response to this demand growth, global production of PrNd oxide has more than doubled and prices have appreciated overall.

As a consequence of the balance problem and the pervasive overproduction of some rare earth elements (e.g., cerium) to keep up with rapidly growing demand for other rare earth elements (e.g., PrNd oxide), prices have diverged in recent years with the latter increasing and the former falling overall since 2017.

For the sake of comparability and consistency, prices of products sold by MP Materials are presented in terms of oxide or oxide equivalent herein. Concentrate prices are a function of the individual rare earth elements they contain and thereby tend to follow an aggregate value trend.

PrNd Oxide

Five-year prices for PrNd oxide can be broken down into three trends:

1. Relatively flat prices from 2017 to July 2020, following a minor spike in 2017

2. Sudden, rapid increase in prices from October 2020 to February 2022

3. Steady decrease in prices from February 2022 to July 2023, with a minor increase since

From 2018 to February 2022, PrNd oxide prices more than tripled, from US$50/kg to over US$150/kg.

The rapid increase in PrNd oxide prices was underpinned by growing demand for NdFeB magnets and the relatively limited supply of PrNd oxide available to produce these magnets. From 2018 through 2021, Adamas data shows that global demand for NdFeB magnets increased at a CAGR of 10%, challenging the ability of the supply side to keep up.

In early 2022, following complaints from rare earth users and industry, Chinese authorities encouraged major producers in the nation to reduce prices which, coupled with the weakening of economic conditions, resulted in a gradual 64% drop in PrNd oxide price by June 2023. Since June 2023, prices have trended higher overall and remain well above October 2020 levels.

Figure 16-2 shows PrNd oxide price history since 2017.

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Source: Adamas, 2023

YTD = January through September

Figure 16-2: PrNd Oxide Price History

SEG+ Oxide

The five-year history for SEG+ oxide (which includes Sm, Eu, Gd, through to Y) follows a similar trend to that of PrNd oxide, though average annual prices have increased overall by 287%, from US$9.64/kg to US$37.39/kg, lifted higher by a rise in prices of dysprosium and terbium, which are minor but valuable components of the mixture. SEG oxalate with specifications of MP Materials’ product mix have a higher sales price, as will be discussed, but follows the same trend as most quoted SEG concentrates.

Driven by dysprosium and terbium’s use in high performance permanent magnets for electric vehicles and wind power generators, their prices have performed strongly overall since 2020, translating to a comparable uptick in SEG concentrate prices overall.

Figure 16-3 shows SEG oxide price history since 2017.

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Source: Adamas, 2023

YTD = January through September

Figure 16-3: SEG Oxide Price History

Lanthanum Oxide

As a casualty of the balance problem, La oxide prices have broadly followed the same downward trend as cerium prices since 2017, dragging down the price of La carbonate at the same time. Much like Ce oxide, the decline in the prices of La oxide and La carbonate is due to pervasive overproduction (i.e., the balance problem) as a consequence of the supply side trying to keep up with rapid demand growth for PrNd oxide.

Figure 16-4 shows La oxide price history since 2017.

Source: Adamas, 2023

YTD = January through September

Figure 16-4: La Oxide Price History

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Cerium Oxide

Cerium is the most abundantly produced rare earth element globally, accounting for approximately 40% of all production. As the main applications of cerium (predominantly in catalytic converters and abrasives) are growing slower than magnet-related applications, cerium has been chronically overproduced for nearly two decades. Cerium is currently finding new end uses and applications, including in lower-performance permanent magnets, but is still in significant oversupply globally.

As such, since 2017, Ce oxide prices have fallen below the cost of production.

Figure 16-5 shows Ce oxide price history since 2017.

Source: Adamas, 2023

YTD = January through September

Figure 16-5: Ce Oxide Price History

16.3.2 Market Balance

Chinese rare earth production quotas have doubled over the past five years, from 120kt in 2018 to 240kt in 2023, leading global mine production of PrNd oxide to increase by 62%. Over the same period, global demand for NdFeB magnets increased by a comparable 60% overall, resulting in a relatively tight supply demand balance. Adamas expects oversupply in 2023 but from 2024 onwards we expect the market will experience a growing and sustained deficit of PrNd oxide through the end of the forecast period.

Adamas expects the start-up of several new projects will slow growth of the market’s deficit between 2025 and 2029 but production will increasingly struggle to keep up with demand growth in the years thereafter.

Figure 16-6 shows the base case PrNd market balance.

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Source: Adamas, 2023

Figure 16-6: Supply Gap Growth to Accelerate from Late-2020s without Prompt New Investment

In Figure 16-7, Adamas shows the long-term market balance for the accelerated supply growth scenario that sees the addition of 20 new “advanced” producers outside of China (over and above the base case) coupled with accelerated demand growth for NdFeB magnets for electric vehicle traction motors, wind power generators and other applications.

Source: Adamas, 2023

Figure 16-7: Adamas Accelerated Supply Growth Scenario Envisages Moderately Balanced Market Until Early 2030s Before Deficit Growth Accelerates

The price response to the expected market deficit is uncertain, but historically minerals and commodity markets experience upward price reactions when supply is unable to meet demand. As such, if expected

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conditions materialize, rare earth inputs for NdFeB magnets – namely PrNd, Dy and Tb – are likely to experience price increases.

As shown in Figure 16-8, Adamas expects the price of PrNd oxide to increase from US$70-80/kg this year to US$120-130/kg in the mid-2020s. While the outlook is uncertain, in a rational market we would expect these price increases to induce investment in new production capacity. However, owing to the long lead times to develop new rare earth supplies and the lack of advanced, financially committed projects in the pipeline today, Adamas sees potential for pervasive deficits to push prices above required inducement levels (estimated at US$100-150/kg in the long term).

By 2035, Adamas projects that EVs, wind power generators and other energy-efficient motors, pumps and compressors will drive nearly two-thirds of global rare earth permanent magnet demand.

This evolution is noteworthy as it implies that the future of magnet rare earths demand will be less sensitive to price than that of the past because future demand will be increasingly driven by applications in which the use of rare earth permanent magnets imparts an economic benefit at the system level.

Be it through battery cost thrifting in an electric vehicle, maintenance cost savings in a wind farm, or electricity cost savings in an industrial facility, grocery store or hotel, the economic upsides enabled by using technologies based on rare earth permanent magnets allow for a significant rise in magnet rare earth prices going forward before it would be economically justifiable to switch to a REE-free alternative.

As such –Adamas expects that the future of rare earths demand (at least in the case of PrNd, Dy and Tb) will be more robust, more resilient and less sensitive to price than demand of the past and present, which is still largely driven by consumer and legacy automotive applications.

Source: Adamas, 2023

Figure 16-8: Adamas Base Case PrNd Oxide Price and Market Balance Forecast

In 2023, Adamas expects that global PrNd oxide supply will exceed global demand by 3% but by 2024 the market will underproduce by over 5% resulting in the drawdown of historically accumulated inventories, the accelerated consumption of cerium and gadolinium as alternatives, and ultimately, a growing deficit through the end of the forecast period.

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Overall, for the global market to effectively balance production and demand from 2026 through 2040 will require the addition of 270,000 to 340,000 tonnes of LREO-rich production by 2040, over-and-above the production growth already expected, which is highly unlikely to happen in Adamas’ view.

Long Term Balance

The long-term market balance for the collective REE suite is expected to be in oversupply due to the balance problem (i.e., the sacrificial overproduction of some rare earth elements, such as cerium, to keep up with rapidly growing demand for other elements and compounds, such as PrNd).

Figure 16-9 shows the market balance forecast for Ce oxide and PrNd oxide.

Source: Adamas, 2023

Figure 16-9: Rare Earth Market Balance Forecast

Looking forward, while markets for magnet rare earths (namely PrNd, Dy and Tb) are expected to experience long-term deficits, markets for cerium, lanthanum and yttrium are expected to be in relative oversupply as a consequence of strong magnet rare earths demand growth. Increasingly, Adamas expects magnet rare earth prices will appreciate to account for the losses producers are chronically incurring by necessarily overproducing other surplus rare earth elements.

16.3.3 Costs

Globally, rare earth production costs are a function of multiple factors, including geology, mineralogy, operational logistics, processing infrastructure, process design and regulatory regime.

The opacity of rare earth production costs and reporting in China, the world’s largest production center, make a transparent comparison between producers challenging.

Through the lens of several key production cost drivers, MP Materials presents apparent advantages and disadvantages relative to major producers in China. On balance, the factors point to MP Materials being a global low-cost producer of rare earth concentrate and oxide.

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Geology and Mineralogy

At MP Materials’ Mountain Pass mine, mined ore contains greater than 6.3% TREO on average versus 4% to 6% TREO at the Bayan Obo mine in China, the nation’s largest, highest-grade source of production and host to over 80% of China’s known rare earth reserves. The higher grade at Mountain Pass and relatively high recovery rates and higher concentrate grade reduces MP Materials’ handling and processing volumes and reduces reagent consumption per ton of ore relative to most major producers.

Logistics

Logistically, the co-location of mining and processing assets at Mountain Pass presents another potential cost advantage for MP Materials versus competitors that ship intermediate products to processing facilities offsite or offshore. This eliminates a precipitation, packaging, shipping, and redissolution step relative to most non-collocated peers.

Conversely, the availability and cost of chemical reagents used to process rare earths is a potential cost disadvantage for MP Materials relative to major producers in China, where reagent costs are lower, and availability is higher. A future restart of chlor-alkali production facilities at Mountain Pass may help reduce this cost disadvantage.

Production Assets

The relatively straightforward ease of beneficiation of Mountain Pass ore, high asset throughput, and high automation help leverage production assets and minimize labor costs.

Conversely, the professionalization of preventative maintenance plans and the costs and logistics of maintaining spare parts and inventory presents a potential cost disadvantage for MP Materials versus major producers in China pursuing a failure-based approach to maintenance.

Regulatory Regime

Relative to major producers in China, Mountain Pass is subject to higher wastewater management and environmental compliance costs owing to a stricter regulatory regime in the U.S., presenting a potential cost disadvantage for MP Materials.

However, at Mountain Pass the dewatering of tailings prior to storage means that over 95% of water used on site comes from recycled sources on site, helping offset the potential cost disadvantage.

16.4 Products and Markets

16.4.1 Mineral Concentrate

Market Overview

Mineral concentrates are a first-stage beneficiation product yielded along the rare earths value chain. Rare earth mineral concentrates vary from producer to producer according to the nature of the deposit, the minerals being recovered and the relative abundance of each rare earth element in those minerals. Mineral concentrate is yielded at a stage prior to separation of rare earth elements from each other and as such contains all individual rare earth elements present in the deposit.

As the largest rare earths producer and processor globally, China is home to a fluid and active market for rare earth mineral concentrate and other downstream products. Over the past five years, processors

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and traders in China have actively imported growing volumes of rare earth mineral concentrates from abroad and invested in development of foreign sources of supply.

Outside of China, third-party imports and processing of mineral concentrates have been relatively limited to-date owing to limited processing capacity. While MP Materials’ supply to China has grown substantially over the past five years, it is expected this will wane in the years ahead as MP Materials ramps up in-house processing and production of separated PrNd oxide in the U.S.

Figure 16-10 shows the mineral concentrate price forecast.

Source: Adamas, 2023

Note: Forecast specific to MP Materials’ Mineral Concentrate

Figure 16-10: Mineral Concentrate Price Forecast

Adamas expects a rare earth mineral concentrate with MP Materials’ composition and purity will have a long-term average price of US$10.94/kg of contained REO. The mineral concentrate price will be principally driven by trends in PrNd oxide price, with expected PrNd oxide price movements to be mirrored by concentrates.

Buyers

At present, buyers are owners and operators of Chinese processing and separation facilities. According to Adamas data, there are over 30 separate legal entities in China with notable processing and separation capacity. These entities purchase mineral concentrate, crack and leach into a chemical solution, and then separate into individual rare earth products according to market-desired specifications. Producers of separated La, Ce and PrNd products often also yield a mixed Sm-Eu-Gd-HREE chemical precipitate which is sold to HREE-focused separation plants with the required production lines.

Sellers

Sellers are rare earth mining operations producing a mineral concentrate. At present, the only known significant mining operation supplying this market outside of China is MP Materials’ Mountain Pass and, with the exception of emerging byproduct monazite producers, this is not expected to change in the near-term. In Adamas’ view, the majority of incoming rare earths production capacity in the near-term

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will aim to produce a mixed rare earth chemical precipitate (e.g., mixed rare earth carbonate), or even separate the product themselves.

Traders

Key traders of rare earth mineral concentrates reside mainly in China due to the presence of abundant capacity and a merchant processing industry there. Shenghe Resources is known to be an active importer and trader of rare earth mineral concentrate, which it distributes to processing and separation facilities in China.

Required Product Specifications

In order to be economical, concentrate grades require a minimum relative abundance of high value elements. Generally, for a LREE-rich mineral concentrate, a relative abundance of PrNd oxide above 10% is acceptable, however, this depends on the entire basket distribution since elevated concentrations of dysprosium and terbium, for example, could reduce this threshold.

The REO grade for commercially traded mineral concentrates varies from around 15% to 73%.

Typical Sales Terms

Sales terms are based on the value of contained rare earths in the concentrate, minus a discount for value added tax (VAT), implied processing costs, profit margin and other relevant penalties, as discussed below.

Treatment Charges / Refining Charges

Due to the opaque nature of concentrate markets, the terms for treating concentrates are relatively uncertain. The number of concentrate transactions globally is relatively small, and the terms for custom concentrate treatment are generally not disclosed by market participants.

In general, Adamas analysis shows that high purity rare earth mineral concentrates in China trade at a price level equal to 30-40% of the rare earth oxide value they contain, whereas some mineral concentrates imported into China sell at a higher 50%+ of contained value because they bear preferential properties (e.g., pre-roasted, high grade, low presence of acid consuming minerals, etc.) or because processors have dialed in their facility for that particular feedstock. This implies a treatment charge of US$4-$10/kg.

Typical Penalty Adjustments

Penalty adjustments can be applied if concentrates contain high levels of non-REE material. Examples include thorium and/or uranium content in monazite mineral concentrates. At above 0.2% thorium and/or uranium content by weight, monazite concentrates may need to be exported under specific restrictions as they will be treated as Class 7 radioactive material. Provincial-level disposal facility charges may apply for radioactive byproduct and there are limited number of processing facilities with the proper licenses to process certain monazite. The cost and operational risk of removing this material and subsequently disposing of it is moderate, and therefore can result in moderate penalty adjustments.

There may be further penalty adjustments for excessive moisture content and elevated presence of acid consuming minerals. Depending upon the REO distribution and nature of impurities, prices may experience step changes in price for lower contained REO grade.

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16.4.2 PrNd Oxide

Market Overview and Pricing

Nearly all PrNd oxide consumed globally is used in the production of PrNd alloy and subsequently NdFeB permanent magnets. Small amounts of individual Nd and Pr, as well as mischmetal containing Nd and Pr, are used in other applications, including battery alloys, catalysts, ceramics, laser crystals, metallurgy, pigments and more.

From 2023 through 2040, Adamas forecasts that global demand for PrNd oxide will increase at a CAGR of 7.2%, led by double-digit demand growth for NdFeB magnets in electric vehicle traction motors and wind power generators.

Specifically, from 2023 through 2040 Adamas forecasts that global PrNd oxide demand for passenger EV traction motors, commercial EV traction motors and “other e-mobility” applications will collectively increase at a CAGR of 10.6% on the back of rising demand for passenger BEVs, PHEVs, and light, medium and heavy commercial electric vehicles.

Over the same period, Adamas forecasts that global PrNd oxide demand for direct drive and hybrid direct drive wind power generators for onshore and offshore applications will increase at a CAGR of 10.7% as the increasingly competitive economics of wind power generation (and low maintenance of permanent magnet direct drive generators) spur increased adoption.

Moreover, from 2023 through 2040 Adamas forecasts that global PrNd oxide demand for industrial applications will increase at a CAGR of 4.2%, bolstered by strong demand growth for power-dense energy-efficient motors, pumps, compressors, fans, blowers, elevators, escalators, industrial robots and more.

Additionally, from 2023 through 2040 Adamas forecasts that global PrNd oxide demand for certain emerging and novel end-uses and applications will increase at a CAGR of 12.1%, led by service robots, magnetocaloric chillers and other upcoming applications.

By 2035, Adamas projects that EVs, wind power generators and other energy-efficient motors, pumps and compressors will drive nearly two-thirds of global rare earth permanent magnet demand.

As noted above, this evolution is noteworthy as it implies that the future of magnet rare earths demand will be less sensitive to price than that of the past because future demand will be increasingly driven by applications in which the use of rare earth permanent magnets imparts an economic benefit at the system level.

As such, Adamas expects that the future of rare earths demand (at least in the case of PrNd, Dy and Tb) will be more robust, more resilient and less sensitive to price than demand of the past and present, which is still largely driven by consumer and legacy automotive applications.

Although Adamas anticipates significant supply growth over the forecast period, it appears unlikely that PrNd oxide supply will be able to keep up with demand growth in the near-term, leading to market deficits that Adamas expects may persist for several years. This forecast is sensitive to production expansions in China, which are directed by government, and could exceed expectations in its growth out to 2034.

With PrNd oxide being the key driver of LREE mining economics, Adamas expects the market to strive for balance over the long-term. In the near-term, moderate and steady deficit levels are expected to

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sustain prices at modest levels (US$80-130/kg), incentivizing the development of new supplies. However, with long lead times to develop new supplies, and demand growth accelerating on the back of electric vehicles, wind power generators and more, deficits are expected to widen from the early 2030s, pushing prices higher overall.

The PrNd oxide price forecast is shown in Figure 16-11.

Source: Adamas, 2023

Figure 16-11: PrNd Oxide Price Forecast

Adamas forecasts a long-term average price of US$131.60/kg for PrNd oxide. This forecast is based on the premise that PrNd continues to carry the cost of rare earth production. From 2024 through 2029, Adamas forecasts that prices will increase just slightly as new supplies enter the market, steadying the deficit, but from 2029 through 2034 prices will rise faster as the deficit grows.

Buyers

Buyers of PrNd oxide are divided into two main groups, downstream NdFeB magnet and magnetic alloy producers, and oxide-to-metal plants.

To produce NdFeB magnetic alloys (i.e., bulk NdFeB materials from which final magnets are produced), PrNd oxide must first be reduced to PrNd metal. Some magnetic alloy producers have oxide reduction capacity in-house and thereby purchase and consume PrNd oxide directly, whereas others purchase metals from third-party reduction facilities. As there is no significant profit to be realized in upgrading from oxide to metal, and thus little incentive for standalone reduction facilities, the metallization step of the value chain could become a bottleneck for some emerging magnet and magnetic alloy producers.

At present, global NdFeB magnet and magnetic alloy production is dominated by China, with emerging growth underway in the U.S. and Europe. Major Chinese magnet producers (and thus buyers of PrNd) include JL-Mag, Beijing Zhong Ke San Huan Hi-Tech, Tianhe Magnets and Ningbo Yunsheng. Collectively, Chinese magnet production makes up approximately 90% of global supply with Japan host to nearly all the rest. Major magnet producers outside of China include Proterial, Shin-Etsu Chemical, TDK, all in Japan, and Vacuumschmelze, located in Germany. Emerging producers in the U.S. and Europe include MP Materials, Noveon, GKN Powder Metallurgy and Neo Performance Materials.

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Strong government support for magnet making in the U.S. and Europe suggest that non-China magnet production will grow.

Due to expected market tightness and the opacity of upstream supplies, automotive and wind OEMs are increasingly amenable to purchasing oxides directly and supplying them to third-party metal and magnet makers in order to increase transparency and security of supplies.

Sellers

In the PrNd oxide market, rare earth processors act directly as sellers. Vertically integrated miners with in-house processing plants directly produce and sell PrNd oxide to metal and/or magnet making facilities. Merchant traders play a relatively limited role at present although some are emerging outside of China (e.g., Tradium in Germany).

Key producers, and therefore sellers, of PrNd oxide are currently located predominantly in China, with China Northern Rare Earth Group accounting for the largest portion of the nation’s oxide sales. In China, PrNd oxide is only sold domestically. Foreign buyers can only import individual Nd or Pr oxides from China, which are priced at a premium to PrNd oxide, advantaging China’s domestic consumers.

In 2023, MP Materials started production of separated PrNd oxide in the U.S. By the mid-2020s, Adamas expects that the share of non-China PrNd oxide production will have grown with new output from MP Materials, expansion of Lynas’ production, and the potential of additional volumes from smaller start-up producers and/or minerals sands.

Traders

The role of traders is limited in the PrNd oxide market. With few exceptions, buyers and sellers trade directly with no intermediate participant required. Japanese trading companies (i.e., Sojitz and Sumitomo) are known to participate in the market, mainly to facilitate logistics for domestic users.

Required Product Specifications

PrNd oxide is sold as a mixed oxide, in a concentrated, powdered, form. Compositionally, PrNd oxide commonly contains 75% Nd oxide and 25% Pr oxide, +/- 5%. Minimum purity for PrNd oxide is 99% TREO, of which PrNd/TREO = 99.5%.

Typical Sales Terms

PrNd oxide sales are typically contract based due to the criticality of the raw materials to magnet makers. Typical sales terms (beyond material pricing) in China are opaque. Due to the relatively high value of the product per kilogram, logistics costs are a minor consideration in final sales agreements.

Treatment Charges / Refining Charges

With few reduction facilities outside of China, the terms for refining PrNd oxide are relatively uncertain. Major PrNd oxide producers in China prefer to complete reduction in-house and sell PrNd metal. As such, the terms for custom PrNd oxide refinement are generally not disclosed by market participants.

In general, Adamas analysis shows that the price of PrNd metal in China is consistently 122% to 124% the price of PrNd oxide. Considering the cost structure in China, this implies a treatment charge of US$4-10/kg.

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Typical Penalty Adjustments

Inferring from the product specifications, no specific penalty adjustments are applicable for PrNd oxide. The typical 99% minimum grade specifications mean that anything below this purity would be scrutinized and potentially face material reductions in agreed price, if not be rejected entirely.

16.4.3 SEG+ Oxalate, Carbonate, Chloride and Oxide (SEG+ precipitate)

Market Overview and Pricing

SEG+ precipitate is an intermediate product comprised of a mixture of medium and heavy rare earths. It is generally made up primarily of so-called medium rare earths (samarium, europium and gadolinium - SEG), with lesser amounts of heavy rare earth elements, including around 4% dysprosium and terbium. Most producers of separated La, Ce and PrNd products often also yield a mixed SEG+ chemical precipitate, such as a carbonate, oxalate or chloride, which may be converted to oxide and sold to HREE-focused separation plants that have the required production lines.

There is no defined end use market for SEG+ precipitates other than as an intermediate feedstock for further processing and separation into market desired individual rare earth products. SEG+ precipitate prices and treatment terms are therefore relatively uncertain and opaque.

The end uses of rare earth elements contained in SEG+ precipitate range from permanent magnets (Sm, Gd, Tb, Dy, Ho) to phosphors (Eu, Tb, Y) to glass additives (Er, Gd, Y) and more. As a result, the market demand and prices of SEG+ precipitate are driven by a variety of factors and considerations.

End use demand growth is inherently variable, thus a market balance for SEG+ precipitate as a single product is not necessarily indicative of pricing or current market dynamics. Like mineral concentrate, the market for SEG+ precipitate is driven entirely by its composite parts. The elements contained in SEG+ precipitate most likely to drive pricing changes are dysprosium, terbium, gadolinium and holmium – elements used in NdFeB permanent magnets with insufficient supply responses expected in the years ahead. Persistent market tightness will help these elements drive SEG+ precipitate prices to higher levels.

As SEG+ precipitate contains a variety of elements, most of which will likely experience demand growth lower than magnet metals (e.g., Eu, Er, Y), the market for the combined SEG+ products as individual oxides is expected to be in surplus over the long term. In fact, owing to the relatively high concentration of Sm and Y in SEG+ precipitate, supply may exceed demand by double by 2040 at current trends. Despite this collective surplus, SEG+ prices may still be favorable as markets for dysprosium and terbium are also expected to experience growing deficits over the coming decade. The capacity for these markets to remain supplied is challenged by HREE resource scarcity in China and political uncertainty in Myanmar.

The principal global sources of supply for dysprosium and terbium as separated products are ion adsorption clay (IAC) mining operations in China and Myanmar, plus minor volumes from SEG+ chemical precipitates yielded by PrNd, La and Ce oxide separation plants.

The only notable IAC operations today are in China and Myanmar although others are being explored elsewhere. China’s operations are expected to face significant stress in the near-term due to resource depletion and scarcity. Myanmar’s operations, which have experience extensive shutdowns and social resistance since 2020, face an uncertain future in light of the political and environmental situation there.

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Closures of ionic adsorption clay operations in either country may lead to pronounced deficits in the dysprosium and terbium markets.

The SEG+ precipitate price forecast is shown in Figure 16-12.

Source: Adamas, 2023

Figure 16-12: SEG+ Precipitate Price Forecast

Adamas expects an increase in the SEG+ precipitate price out to 2034 due mainly to expected increases dysprosium and terbium prices. Adamas forecasts a long-term average price of US$51.90/kg for a SEG+ precipitate with MP Materials specifications. This price is built up on internal modelling of Chinese separation facilities’ costs of production and required feedstock price (at which they would purchase the material) to meet profitability targets of 10-20%. It is unclear exactly how terms will develop over the coming years.

Buyers

Key buyers of SEG+ precipitate are Chinese separation facilities capable of separating heavy rare earths. As discussed in Section 16.4.1, Adamas notes the existence of at least 30 separate legal entities in China with significant commercial capacity for rare earth separation through solvent extraction.

Over time, buyers are expected to emerge in other regions, such as the U.S., Australia and Europe, where heavy rare earth processing capacity is being developed, including internally at MP Materials.

Sellers

Sellers are typically facilities with light rare earth separation capacity. Typical light rare earth separation facilities have too little Dy and Tb in their feedstock to economically justify the construction and operation of heavy rare earth separation lines thus they precipitate these elements into a mixed SEG+ chemical concentrate for sale to plants with HREE separation capacity.

Traders

Outside of China, it is understood that Lynas Rare Earths conducts a monthly auction for the SEG+ precipitate it produces in Malaysia.

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Required Product Specifications

There are no required product specifications for SEG+ oxalate, however, the costs of consuming SEG+ oxalate to produce separated rare earth oxides are high thus it must contain a high enough concentration of valuable elements to be viable.

Typical Sales Terms

The sales terms SEG+ oxalates are generally opaque, given the limited number of sellers of the product (i.e. currently Lynas with MP Materials beginning to participate). As price participants, we understand that in China the product, like other mixed rare earth intermediates, may be purchased on the basis of a percentage of contained rare earth value.

Treatment Charges / Refining Charges

Due to the opaque nature of intermediate markets, the terms for treating SEG+ precipitate are relatively uncertain. The number of SEG+ precipitate transactions globally is small, and the terms for custom concentrate treatment are generally not disclosed by market participants.

In general, Adamas analysis shows that high purity mixed rare earth precipitates in China trade at a price level equal to 65-80% of the rare earth value they contain.

Typical Penalty Adjustments

Potential penalty adjustments may be made if the SEG+ oxalate does not contain enough dysprosium and/or terbium to be considered economic for processing.

16.4.4 La Carbonate

Market Overview and Pricing

The U.S. is the largest consumer of imported La carbonate globally. Currently, it is understood that no La carbonate (outside of the recent launch of MP’s production capability) is produced in the U.S., meaning domestic production may replace existing imported supply.

In recent years, U.S. imports of La carbonate have ranged from ~5 kt to 15 kt albeit volumes are declining over time. The main use of La carbonate is in fuel cracking catalysts and catalytic converters for gasoline-powered vehicles, both applications that have been negatively affected by rising global sales of electric vehicles.

In the fuel industry, La-containing catalysts are used to break down crude oil molecules into market-desired distillates, such as gasoline, kerosene, diesel and more. Adding lanthanum to fuel cracking catalysts increases gasoline make, which, next to diesel, has seen demand challenged by rising electric vehicle adoption globally.

Moreover, La carbonate is sometimes also used alongside cerium in catalytic converters of gasoline-powered vehicles in which rare earths and other precious metals help reduce pollutants in the vehicle’s exhaust stream into less harmful varieties.

Relatively small amounts of La carbonate are also used in the pharmaceutical sector, consumer electronics sector, certain metals and alloys, and in wastewater treatment for phosphate removal - more detail is provided for the water treatment market in Section 16.4.5.

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Like cerium, the market balance of lanthanum is heavily influenced by the balance problem. In a typical bastnaesite or monazite deposit, lanthanum makes up 20-35% of the contained TREO whereas lanthanum’s share of overall TREO demand is a lower 15% resulting in pervasive overproduction.

With PrNd demand expected to drive TREO production growth over the long term, the amount of sacrificially overproduced lanthanum will increase in tandem.

As a result, in both the near- and long-term, the market for lanthanum will continue to be oversupplied, and the extent of oversupply will continue to grow unless new end-uses and applications for lanthanum emerge. In the near-term, however, with lanthanum oxide prices having fallen below the cost of production, and inventories in the relatively disciplined hands of China’s major producers, we expect lanthanum and cerium oxide, carbonate and chloride prices to appreciate moderately and then stay relatively flat across the remainder of the forecast period.

Figure 16-13 shows the lanthanum carbonate price forecast.

Source: Adamas, 2023

Figure 16-13: La Carbonate Price Forecast

Lanthanum carbonate prices closely track oxide prices. Adamas forecasts a long-term average price of US$1.50/kg for La carbonate (on La oxide equivalent basis). This forecast is calculated on the basis of the relationship between historic lanthanum carbonate and oxide prices. As a product in chronic oversupply, the costs of production are mostly covered by PrNd oxide, meaning that there is no current inducement or incentive price for lanthanum.

Buyers

Buyers of La carbonate include fuel cracking catalyst manufacturers, catalytic converter washcoat manufacturers, and others consuming lanthanum for use in medical products, consumer electronics, metals and alloys, and in wastewater treatments.

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Sellers

The main sellers of lanthanum carbonate are rare earth separation facilities. With conventional solvent extraction, lanthanum requires separation from the rare earth mixture before more valuable products, such as PrNd, thus the vast majority of LREE separation facilities globally will produce a lanthanum product, be it oxide, carbonate, chloride or other. We believe MP Materials is currently the only commercial scale lanthanum carbonate producer in the U.S.

Current re-sellers or importers of Chinese lanthanum carbonate in the U.S. for sale downstream will struggle to compete against domestic production since transport and logistics costs of low value lanthanum products may account for more than half of their landed costs.

Traders

In the case of La carbonate, vertically integrated miners with in-house processing plants produce La carbonate for sale to downstream consumers, or sale to local and foreign traders that sell to downstream consumers. The majority of La carbonate is currently produced in China, making MP Materials the only known domestic U.S. producer. Current re-sellers in the U.S. and Europe market imports of concentrates from China.

Required Product Specifications

Typical La carbonate is marketed as a powder containing 45% TREO minimum and with La₂O₃/TREO of at least 99.5%.

Typical Sales Terms

The sale of La carbonate is contract based with no official spot price reported globally. It is understood that contracts typically include fixed supply periods between buyers and sellers at a fixed rate, renegotiated periodically as a function of La oxide price. Buyers usually pay transportation costs.

Treatment Charges / Refining Charges

As a light rare earth product in surplus, and a sacrificial byproduct of PrNd, treatment charges for this product do not exist in isolation – the economics of magnets rare earths will factor in.

Typical Penalty Adjustments

Potential trade penalties may exist where the La carbonate sold to a seller is below 45% TREO including free moisture and LOI or contains less than 99.5% La₂O₃/TREO.

16.4.5 Cerium Chloride

Market Overview and Pricing

The market for Ce chloride is led by vertically integrated miners and companies with in-house processing plants that produce and sell material to downstream consumers as a branded product.

One of the primary uses of Ce chloride is as a coagulant (a substance which causes curdling and clotting of liquids) in the water treatment sector. Ce chloride is an alternative to traditional coagulants in this sector where it is well suited for phosphorous (P) removal.

Based on U.S. Environmental Protection Agency (USEPA) mandates, companies and water treatment facilities in the U.S. are required to maintain P levels between 0.05-0.1 mg/L, levels that some traditional coagulants struggle to achieve.

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Buyers of Ce chloride are typically end users of the product, such as water treatment plants. Sellers are those producing the product and often packaging into branded merchandise for marketing to buyers. Traders are the vertically integrated miners or in-house bulk upstream producers of Ce chloride.

Table 16-2: Summary of U.S. Facilities Monitoring and Limiting P-levels

Source: Adamas after USEPA, 2023

Overall, the cerium market outlook is similar to that of lanthanum, with oversupply expected to persist in both the near- and long-term as a consequence of the balance problem. In a typical bastnaesite or monazite deposit, cerium makes up 35-50% of the contained TREO whereas cerium’s share of overall TREO demand is a lower 15-20% resulting in pervasive overproduction.

As such, the market for cerium is expected to face similar price pressures as lanthanum over the forecast period, however, as a phosphate removal product, Ce chloride is not priced as a rare earth product.

At present, the U.S. cerium chloride market is supplied mainly by companies that import cerium oxide or carbonate and subsequently convert it into a chloride in-house. A domestic rare earth mine able to produce cerium chloride on-site may have a cost advantage over its competitors.

Figure 16-14 shows the cerium chloride price forecast.

Source: Adamas, 2023

Figure 16-14: Ce Chloride Price Forecast

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Buyers

With principle use in the water treatment industry, buyers of Ce chloride reside in that same industry. Municipal water suppliers and industrial facilities (power, chemicals, and mining) are consumers and buyers of Ce chloride for treating P. The growing use of P-based fertilizers in agriculture results in increased levels of P within water supplies making regions with the highest P demand among the largest likely buyers of Ce chloride.

Sellers

Sellers of Ce chloride market the material as a branded, packaged liquid compounds, or as a salt for preparing solutions. Although most products utilize Ce chloride in a similar manner, sellers often target their products to specific applications (e.g., pool treatment) for marketing and differentiation purposes.

Traders

Traders of Ce chloride sit upstream of the end use market, including vertically integrated miners with in-house processing plants that sell bulk cerium chloride to downstream sellers. In this regard, MP Materials has the option to act as a trader or a seller or both in this market.

Required Product Specifications

Ce chloride coagulants are sold in liquid or solid form. Typical product contains a minimum of 45% TREO on a dry basis and CeO₂/TREO of at least 80%.

Typical Sales Terms

As a value-added product, market participants (traders) currently buy Ce oxide or chloride salt/flake (mostly from China) and convert it to Ce chloride in the U.S. for sale to downstream re-sellers on a US$/weight-solution basis. Re-sellers then brand and package the product and sell on a similar basis as upstream traders. As such, the product is not treated as a rare earth product and thus is not priced on a rare earth content basis. Pricing may be against comparable coagulants or water treatment products, in particular ferric chloride and alum chloride.

Treatment Charges / Refining Charges

As a light rare earth product in surplus, and a sacrificial byproduct of PrNd, treatment charges for this product, like La carbonate, do not exist in isolation – the economics of magnets rare earths will factor in.

Typical Penalty Adjustments

We do not believe of the primary Ce chloride penalty would relate to product concentration. Low gram/liter of REO could incur shipping and handling penalties. Conversely, domestic production should favor MP Materials since currently domestic sources of Ce chloride are derived from imported and upgraded Ce oxide.

16.5 Specific Products

Forecasts for relevant rare earth product prices are presented in Section 16.4. A brief summary of price forecasts is presented in Table 16-3.

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Table 16-3: Summary of Long-Term Price Forecasts

Product	Long-Term Price Forecast, Real 2023 US$/KG
Rare Earth Mineral Concentrate	10.94
PrNd Oxide	131.60
SEG+ Precipitate	51.90
La Carbonate	1.50
Ce Chloride	2.51

Source: Adamas, 2023

All prices are modelled based on production costs and established market trends where they exist.

16.5.1 Concentrate

Typical Project Specifications

Adamas understands MP Materials’ rare earth mineral concentrate is produced to a grade of roughly 60% TREO, with PrNd oxide making up approximately 15.7% of contained TREO.

Market Space

Adamas understands that concentrate grades typically range from 15% to 73% REO and as such, MP Materials’ concentrate is considered within industry acceptable specifications.

Shipping

Shipment of rare earth mineral concentrate products into China is the responsibility of the supplier, such as MP Materials.

Contract vs. Spot Sales

MP Materials receives revenue from mineral concentrate sales via a contractual agreement with Shenghe Resources with observed sales terms largely reflecting spot market PrNd oxide price movements.

Marketability

MP Materials’ rare earth mineral concentrate product is sold into the Chinese processing market. With ample unused processing capacity available in China, marketability of this product is not considered a risk.

Sales Terms

Rare earth mineral concentrate products are priced based on purity, the distribution of rare earths contained and the prices of contained rare earths, less any applicable penalties. MP Materials’ high TREO content and comparably low levels of thorium/uranium translates to favorable prices for its product.

The prices agreed upon with Shenghe Resources are based on an agreed market benchmark for separated rare earth oxides. The concentrate price agreed contains an implicit treatment and refining charge.

Applied Penalties

Penalties may be applied to concentrates with high radioactive content, as explained in Section 16.4.1., high moisture content, low purity, or a high concentration of acid consuming minerals.

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16.5.2 PrNd Oxide

Typical Project Specifications

PrNd oxide will be produced to industry standard specifications, containing at least 99% TREO and at least 99.5% PrNd/TREO.

Typical PrNd oxide contains 75% Nd oxide and 25% Pr oxide, +/- 5%. MP Materials will produce PrNd oxide to typical specifications +/- 3%, thereby within the limits of acceptability.

Market Space

Variation in the ratio of Nd to Pr is acceptable if the Nd percentage does not fall below 70% and does not exceed 80%, although Adamas believes consumers have a high degree of flexibility in this regard since the main reason magnet makers use PrNd is that it is lower priced than individual Nd or Pr, not because it bears a particular ratio of Nd to Pr.

With MP Materials producing an PrNd oxide product at 99.5% to 99.9% purity, we believe it will satisfy current industry standards.

Shipping

The responsibility of shipping under MP Materials’ contractual obligations for the sale or distribution of PrNd oxide typically falls to the seller, per market norms.

Contract v Spot Sales

With MP Materials starting production of refined PrNd oxide in late 2023, the eventual mixture of spot and contract sales is presently unknown, although the majority of contracts (or contracts under consideration) as of the report date contain a rolling price adjustment based on prevailing market prices. Both contract and spot sales are likely for PrNd oxide.

Marketability

We understand that MP Materials intends to use a portion of its PrNd oxide to produce metals, magnetic alloys and magnets at its Texas magnetics factory currently under construction and sell the remaining portion to existing and emerging metals and magnet manufacturers. With a growing number of magnet plants under development in the U.S. and Europe, and demand for alternative sources of supply in Japan, we believe the PrNd oxide planned to be produced is a marketable and desirable product.

Sales Terms

PrNd oxide is a globally traded material, and we would expect sales terms to reflect known global prices. Material contract terms are generally not disclosed, but we understand MP Materials contracts to be in line with industry norms. We understand that MP Materials does not expect to face penalties associated with the quality of PrNd oxide produced.

Applied Penalties

As PrNd oxide is a refined, market desired product in high purity form, MP Materials does not expect to incur any penalties.

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16.5.3 SEG+ Precipitate

Typical Project Specifications

As a mixed rare earth product, SEG+ precipitates will be produced to typical industry standards for chemical precipitates (45% TREO minimum), as a solid powder. There is no official standard for SEG+ precipitates specifically.

Market Space

SEG+ precipitate prices are heavily influenced by their Dy and Tb contents, with typical SEG precipitates containing around 4%. MP Materials will produce SEG+ oxalate with at least 5% Dy and Tb contents making it a desirable product.

Shipping

We understand that no definitive shipping terms are in place for SEG+ precipitate sales to-date, however, purchasers will likely incur shipping costs for delivery. MP Materials intends to maintain significant SEG+ precipitate inventory in order to eventually separate the SEG+ into separated HREE products.

Contract v Spot Sales

We understand that no contractual agreements are yet in place for SEG+ precipitate thus the eventual mixture of spot and contract sales is presently unknown. Both contract and spot sales are likely for SEG+ precipitate, although MP Materials has expressed an intention to maintain SEG+ precipitate inventory for eventual separation into separated HREE products.

Marketability

If the tight market balance of Dy and Tb that Adamas forecasts materialize, we believe MP Materials should not face significant risk if seeking to sell SEG+ precipitate to Chinese separators or other emerging HREE separation plants outside China.

Sales Terms

Sales of SEG+ precipitate are priced according to the purity of the material and the value of rare earths contained thus are heavily influenced by Dy and Tb. The elevated Dy and Tb content within MP Materials’ SEG+ precipitate suggests that prices should be favorable in reflection of the tight market balance expected for Dy and Tb.

Applied Penalties

SEG+ precipitates with low purity, high levels of LREEs, low Dy and Tb contents (<4%), or requiring additional pre-processing (i.e., roasting to oxide) could incur a penalty. MP Materials is not expected to incur penalties as its SEG+ precipitate is high purity and contains elevated Dy and Tb contents.

16.5.4 La Carbonate

Typical Project Specifications

Typical La carbonate is marketed as a powder containing 45% TREO minimum and with La₂O₃/TREO of at least 99.5%., though no official standard exists. We understand MP Materials plans to sell La carbonate as a nearly anhydrous solid powder with a high purity (>98%).

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SRK Consulting (U.S.), Inc.
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Market Space

The U.S. is the largest consumer of imported La carbonate globally. However, due to the balance problem, La carbonate supply is expected to remain abundant. As a low-priced product, logistics and transportation costs are relatively high for U.S. imports of La carbonate giving MP Materials a competitive advantage in the market.

Shipping

Currently contemplated contracts for La carbonate involve MP Materials covering the cost of domestic shipping, however, certain contemplated contract structures include shipping costs as part of a cost-plus pricing framework.

Contract vs. Spot Sales

Both contract and spot sales are likely for La carbonate, as well as the potential for contracts involving elements of a cost-plus framework (including shipping costs).

Marketability

As a low-cost producer of La carbonate located in the U.S., MP Materials will have a competitive position from which to market its product.

Sales Terms

Sales terms for La carbonate are currently under negotiation with domestic buyers. Domestic availability (and thus reduced logistics and transportation costs for buyers, as well as supply chain security) can help ensure marketability for MP Materials’ products.

Applied Penalties

As the La carbonate produced by MP Materials is expected to meet specifications for use in catalysts and other applications, it does not expect to incur any penalties.

16.5.5 Cerium Chloride

Typical Project Specifications

Ce chloride coagulants are sold in liquid or solid form. Typical products contain a minimum of 45% TREO on a dry basis and CeO₂/TREO of at least 50%. MP Materials will sell Ce chloride in a liquid form, with low levels of La chloride as well (<20%).

Market Space

While demand for Ce chloride is not expected to keep up with growth in Ce oxide supply, promising new markets for Ce chloride are materializing – such as the water treatment market. No known domestic producers of Ce chloride exist within the U.S. at present, offering MP Materials an economical and logistical advantage.

Shipping

No international shipping of Ce chloride is expected, MP materials will distribute Ce chloride domestically. Purchasers will cover shipping costs.

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SRK Consulting (U.S.), Inc.
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Contract v Spot Sales

MP Materials may utilize both contractual and spot sales, catering to smaller independent consumers and national-scale municipal consumers.

Marketability

Ce chloride use in the water treatment sector is a relatively new approach, with room for growth as a replacement of traditional chemicals used in this space. As a low-cost producer of Ce chloride located in the U.S., MP Materials will have a competitive position from which to market its product. Risks faced would include the immature market for Ce chloride in the water treatment sector.

Sales Terms

Sales of Ce chloride are priced on a dollar-per-weight-solution basis. Since Ce chloride is not marketed as a rare earth product, both spot and contractual sales would expectedly cover the cost of production.

Applied Penalties

Excessive La chloride content (>20%) would likely cause MP Materials to incur a penalty. As MP Materials has flexibility to control lanthanum content based on customer demand, this penalty is not expected to be applied.

16.6 Conclusions

This report provides an overview of key trends within the rare earths market. Analysis outlined in this report reveals a high degree of variability in the demand profiles of individual rare earth elements and their associated end-uses.

Consequently, a strong demand outlook for PrNd oxide – the main rare earth input for NdFeB permanent magnets - drives a weak supply outlook for Ce and La products, which are sacrificially overproduced as a function of keeping up with magnet demand.

While centered in China, the rare earths market is increasingly global with suppliers and potential suppliers emerging around the world. This report highlights the favorable demand conditions that non-China producers may face as they enter the market but also highlights the unfavorable supply side conditions end users can expect without prompt new investment into new production.

Products outlined in this report (PrNd oxide, SEG+ precipitate, La carbonate, Ce chloride and rare earth mineral concentrate) are desirable from a market perspective, provided market standards and requirements are met.

Many of the near-term risks facing players in the rare earths market are political, with past disputes responsible for exacerbating volatility of REE prices. Specific risks to products are highlighted where perceived, though the indicated specifications and communicated sales terms enforce the conclusion that products are both desirable and marketable.

16.7 Contracts

Information pertaining to contracts associated with MP Materials’ current and future operations was obtained from conversations between Adamas and MP Materials. As such, Adamas can only comment on the status of contractual agreements described to it by MP Materials and based on Adamas’ understanding of normal commercial practice and prevailing market conditions.

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Adamas understands that MP Materials is an existing producer satisfying all contracts required for the functioning of current operations. Current production of rare earth mineral concentrate is sold under contract to an offtake partner (Shenghe).

We understand that the pricing terms and other contractual stipulations of the existing contract are in line with industry and broader global market terms. This, along with other contracts needed to sustain current and future operations, is the extent of MP Materials’ currently executed contracts.

Having commenced internal separation of oxides in late-2023, we believe MP Materials aims to increasingly consume its own concentrate to produce the following product mix:

• PrNd oxide

• SEG+ precipitate

• Lanthanum carbonate

• Cerium chloride

Adamas understands that MP Materials is in discussion with potential consumers and distributors of these separated products and aims to finalize these contracts as it ramps up production. In February 2023, MP Materials and Sumitomo Corporation announced an agreement whereby the latter will serve as the exclusive distributor of PrNd oxide produced by MP Materials to Japanese customers. We believe the current state of negotiations is in line with standard practice for a new minerals producer seeking to qualify a new product with customers. The planned separated products are more abundantly traded than mineral concentrates and we believe ongoing negotiations are likely to lead to industry standard agreements and terms.

Adamas understands that MP Materials’ present offtake partner (Shenghe) may reasonably be deemed an affiliated party due to Shenghe’s minority equity interest in MP Materials. To our knowledge, Shenghe is the only notable affiliated partner for the purposes of this review of commercial contracts.

Based on information reviewed by Adamas, it appears that offtake terms with Shenghe do not disproportionally benefit either party involved through non-standard commercial terms. Adamas believes that current terms with Shenghe are reasonable and fair for offtake agreements with non-affiliated third parties.

Based on guidance provided by MP Materials, Adamas understands that MP Materials maintains various operational contracts with external parties to support current and future operations. The operational contracts include, but are not limited to, a variety of services including those listed below.

• Chemical reagent procurement

• Industrial gas procurement

• Natural gas procurement

• Drilling services

• Blasting services

• Freight carrier services

• Supplemental contract labor services

• Equipment maintenance services

• Equipment rental services

• Environmental monitoring services

• Analytical services

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• Security services

• Insurance and risk management services

• Information technologies and support services

In addition, Adamas understands (based on guidance provided by MP Materials) that MP Materials fulfils and maintains contracts, services and other requirements for recommissioning, functioning and operating its separation facility. These contracts have been understood to include:

• Engineering, Procurement, and Construction (“EPC”)

• Engineering services

• Owner’s representation

• Procurement services

• Supplemental contract labor services

The existence and maintenance of these contractual arrangements is in line with Adamas’ understanding of normal commercial practice for a company such as MP Materials.

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SRK Consulting (U.S.), Inc.
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17  Environmental Studies, Permitting, and Closure

The following discussion of environmental studies, permitting, and community impacts presents an overview of recent environmental impact reports and active environmental permits.

17.1  Environmental Study Results

In 2004, the previous owner completed an environmental assessment process to gain approval for a 30-year mine plan. The legal framework for the environmental assessment process was the California Environmental Quality Act, and the lead regulatory agency was San Bernardino County (SBC). The final Environmental Impact Report (EIR) described the proposed action and assessed baseline environmental conditions for aesthetics, air quality, biological resources, cultural resources, geology/soils, hydrology/water quality, and noise. This environmental assessment process included extensive public consultation as well as inter-agency (state and federal) collaboration. SBC certified the final EIR in 2004.

17.2  Required Permits and Status

In 2004, the Land Use Services (LUS) Department of SBC (SBC-LUS) approved the 30-year open pit mine plan, including an ultimate open pit design. The SBC-LUS issued a Conditional Use Permit (CUP) based on mitigation measures identified in the final EIR. In 2010, the previous operator applied for a modification to the 2004 approved land use to accommodate process improvements and the elimination of 100 acres of evaporation pond area approved in the 2004 CUP. The SBC-LUS approved the Minor Use Permit (MUP) and issued the updated Mine and Reclamation Plan (2004M-02) in November 2010.

The previous owner revised the approved Mine and Reclamation Plan in 2015. The SBC approved the change of ownership to MP Mine Operations LLC (dba MP Materials) in 2017. In April 2021, MP Materials filed an application for Stage 2 Facilities Construction (previously approved under the 2010 MUP and vested under the Mining and Reclamation Plan). This application includes constructing, redesigning, improving and/or re-locating several processing facilities identified in the 2010 MUP. MP Materials received formal approval of the modification of the MUP to proceed with the Stage 2 Facilities Construction plan in April 2021.

The future mine plan expands the current permit boundary. The previous owner and MP Materials demonstrate a proactive and constructive dialogue with the SBC-LUS on previous modifications of the Mine and Reclamation Plan (e.g., 2010, 2015 and 2021). The change in the future open pit boundary is within the existing mine disturbance.

MP Materials plans to expand the North Overburden Stockpile, relocate a stormwater diversion channel and relocate the primary crusher (2028). The stockpile expansion and primary crusher relocation will require a permit amendment. The proposed action for the stormwater diversion channel will be a minor amendment. Based on their recent record of permit applications and approvals with regulatory authorities, MP Materials estimates the longest duration of regulatory review and approval of an amendment to be less than 18 months. Minor amendments typically require less than 6 months. MP Materials schedules application submittal dates based on these durations.

The future mine plan also requires construction of a new, 142 million short ton East Overburden Stockpile by 2030. The 2004 EIR considered a tailings storage facility east of the processing area. MP Materials will need to engage with the SBC-LUS and allow sufficient time to assess if a mitigated

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negative declaration is possible or if additional data collection will be required before SBC-LUS will consider a new application.

Since 2017, MP Materials demonstrated a pro-active, working relationship with the SBC-LUS and other regulatory authorities. This relationship includes timely and successful permit amendments and approvals for current operations. SRK is of the opinion that MP Materials will continue to successfully engage regulatory authorities and gain approval for future amendments related to site operations within the private property boundary.

Table 17-1 presents a summary of current Mountain Pass environmental permits.

Table 17-1: Current Environmental Permits and Status

Permit	Agency	Expiration Date
Right of Way for the Shadow Valley Fresh Water Pipeline CA12455	Bureau of Land Management	12/31/2041
San Bernardino County Domestic Water Supply Permit #36000172 (Duplicate of PT0006375)	San Bernardino County Departmentof Public Health	No Expiration
EPA Identification Number CAD009539321	US Environmental Protection Agency	No Expiration
Hazardous Materials Certificate of Registration	US Department of Transportation	6/30/2024(1)
NRC Export License XSOU8707/08	US Nuclear Regulatory Commission	12/31/2031
NRC Export License XSOU8827/03 (2)	US Nuclear Regulatory Commission	12/31/2031
Conditional Use Permit 07533SM2/DN953-681N	San Bernardino County Land UseServices Department	11/23/2042
CUPA Annual Permit FA0004811	San Bernardino County FireProtection District	9/30/2024
LRWQCB Order 6-01-18 Domestic Wastewater System	Lahontan Regional Water QualityControl Board	No Expiration
LRWQCB Order R6V-2005-0011On Site Evaporation Ponds	Lahontan Regional Water QualityControl Board	No Expiration
LRWQCB Order R6V-2010-0047 - Mine and Mill Site, including paste tailings	Lahontan Regional Water QualityControl Board	No Expiration
Mojave Desert Air Quality Management District - Permits to Operate	Mojave Desert AQMD	2/28/2024(3)
Right-Of-Way Lease 6375.2	California State Lands Commission	1/19/2032
Radioactive Materials License #3229-36 for ongoing operations and Paste Tailings	California Department of PublicHealth — Radiologic Health Branch	12/21/2032
Right of Way for the Shadow Valley Fresh Water Pipeline CA12455	Bureau of Land Management	Active
Minor Use Permit - Project Phoenix (Amended Reclamation Plan)	San Bernardino County	11/22/2042

Source: MP Materials, 2023

⁽¹⁾: Renewed annually.

⁽²⁾: New License replaces XSOU8708.

⁽³⁾: Mojave Desert Air Quality Management District online records indicate the Mountain Pass operation (Facility ID 364) held approximately 272 individual air quality related permits within the last 22 years. This historical total includes discontinued unit operations. The permit record indicates timely renewals and approvals, including extensions.

17.3  Mine Closure

Mine closure obligations consist of the Mine and Reclamation Plan administered by the SBC, groundwater and surface water measures administered by the LRWQCB, and decommissioning requirements by the California Department of Resource, Recycling and Recovery. SBC and LRWQCB permit authorizations also stipulate post-closure inspection, maintenance, and monitoring activities. Table 3-1 summarizes the current closure, reclamation, and post-closure obligations for the Mountain Pass property.

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SRK Consulting (U.S.), Inc.
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18  Capital and Operating Costs

Capital and operating costs are incurred and reported in US dollars and are estimated at a pre-feasibility level with an accuracy of approximately +/-25%.

18.1  Capital Cost Estimates

The mine is currently operating and, as such, there is no initial capital expenditure required. All capital expenditure as contemplated by this report is expected to be sustaining capital. Sustaining capital expenditures include the sustaining capital cost associated with the mining fleet, separations facility, planned paste tailings plant, crusher and water tank relocations, tailings storage facility expansion, and the “other” category, which captures all other sustaining capital costs.

18.1.1  Mining Capital Cost

The operation is being run as an owner mining operation. A contractor will perform all drilling and blasting operations.

Table 18-1 shows the annual mining equipment capital costs, as estimated by SRK.

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Table 18-1: Mining Equipment Capital Cost Estimate (US$000’s)

Capital Costs	2023		2024		2025		2026		2027		2028		2029		2030		2031		2032		2033		2034		2035		2036		2037		2038		2039		2040
Mobile Equip. (Purchases)
Loading
Hauling				1,440		2,691		1,346																						1,346				1,346
Other Ops (1)				718																937				1,561				1,224				755		671		671
Support (2)								1,083		84		1,087		599				903		1,411		829		1,482		84						1,595				829
Subtotal Purchases				2,157		2,691		2,428		84		1,087		599		-		903		2,348		829		3,043		84		1,224		1,346		2,350		2,016		1,499
Mobile Equip. (Rebuilds)
Loading				460				695								460						695		1,154										460		1,390
Hauling										1,009								202		1,117				202		2,018								404		807
Other				281		141		569		508		382				950				428				201		141		201				656				281
Support				271		271		445		271		271				445								135		135				493		271				271
Subtotal Rebuilds		-		1,011		411		1,708		1,787		652		-		1,855		202		1,544		695		1,693		2,294		201		493		926		863		2,749
Mining Equip. Total		-		3,169		3,102		4,137		1,871		1,739		599		1,855		1,104		3,892		1,524		4,736		2,378		1,425		1,839		3,276		2,879		4,248
Capital Costs	2041		2042		2043		2044		2045		2046		2047		2048		2049		2050		2051		2052		2053		2054		2055		2056		LoM Total
Mobile Equip. (Purchases)
Loading														2,316																				2,316
Hauling				4,037																														12,206
Other Ops										937										1,224				1,561										10,259
Support		599				84		1,411		903				829		1,087		1,482		508		84				599		549						18,121
Subtotal Purchases		599		4,037		84		1,411		1,839		-		3,145		1,087		1,482		1,732		84		1,561		599		549		-		-		42,897
Mobile Equip. (Rebuilds)
Loading																																		5,314
Hauling		1,117		1,211		807		202				202		404												807								10,509
Other Ops		281		581		382		101				468		428		342										201		508						8,031
Support		715								445				135		135				271		271		222		271		271						6,015
Subtotal Rebuilds		2,113		1,792		1,189		302		445		670		967		477		-		271		271		222		1,279		778		-		-		29,860
Mining Equip. Total		2,712		5,829		1,273		1,713		2,284		670		4,111		1,564		1,482		2,003		355		1,783		1,879		1,327		-		-		72,758

Source: SRK, 2023

Notes:

(1) “Other Ops” includes dozers, water trucks, motor grader and excavator.

(2) “Support” includes mobile equipment used in paste tailings operations, maintenance vehicles, light vehicles and pit dewatering pumps.

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18.1.2 Separations Facility Capital Cost

The separations facility has been constructed and commissioned and is currently in the process of ramping up to full capacity by the end of 2024. As such, future capital costs for the separations facility are treated as sustaining capital costs. The sustaining capital costs, as estimated by MP Materials and SGS, are presented in Table 18-2.

Table 18-2: Estimated Separations Facility Sustaining Capital Costs

Year	Amount (US$000’s)
2024(1)		6,624
2025		6,787
2026		10,180
2027		13,574
2028(2)		26,030
2029 through 2056(3)		475,089
Total		537,924

Source: MP Materials / SGS

(1): Includes US$2,871,000 for a freshwater storage pond.

(2): Includes CHP turbines.

(3): From 2029 through 2056, the estimated annual cost is US$16,967,449.

18.1.3 Other Sustaining Capital

For the purposes of estimating total sustaining capital, SRK utilized the current capital depreciation which is approximately US$3.3 million per year. In SRK’s opinion, this value is a reasonable estimate for long-term sustaining capital for the current operation other than the individually estimated capital items.

In addition to the long-term sustaining capital allowance of US$3.3 million per year, the following non-recurring items have been included in the estimate of other sustaining capital:

• Crusher relocation (2028): US$3.4 million

• Water tank relocation (2035): US$5.6 million

• Paste plant relocation (2035): US$69.7 million

• Tailing storage facility expansion (2047): US$11.3 million

18.1.4 Closure Costs

Closure costs are captured as a capital expenditure during the final year of mine operation in the financial model at a value of US$45.4 million.

18.1.5 Basis for Capital Cost Estimates

Mining Capital Cost

The mining equipment requirements were based on the mine production schedule, and estimates for scheduled production time, mechanical availability, equipment utilization, and operating efficiencies.

Estimates of annual operating hours for each type of equipment were made, and equipment units were utilized in the mining operations until a unit reached its planned equipment life, after which a replacement unit was added to the fleet, if necessary. Major mining equipment rebuild (overhaul) costs were included in the mining equipment capital cost estimates.

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The mining equipment capital cost estimate was based on the following:

• All replacement mining units are based on new equipment purchases.

• Freight cost for mining equipment was generally estimated to be between 3% and 5%.

• Allowances were made for on-site equipment erection costs for some units.

• Mining equipment rebuilds were included at appropriate intervals in the mining capital costs.

Separations Facility Capital Cost

To calculate estimated sustaining capital for the separations facility, MP Materials and SGS used a first principles approach utilizing a proxy of a percentage of invested capital into the plant and accompanying facilities, including the CHP plant, to calculate a reasonable estimate for average required reinvestment. This yielded an estimate of US$17 million per year in long-term sustaining capital for the separations plant and accompanying facilities. Some adjustment of this annual cost was applied to reflect the fact that the facility is new and therefore is likely to experience a reduced rate of sustaining capital expenditures in the first five years of operation.

Other Capital Cost

Costs for the tailings storage facility expansion and relocation of the paste plant, crusher and water tanks were based on an engineering cost estimate. Depreciation values were utilized as a proxy for other sustaining capital.

Closure Costs

Closure cost and post closure cost estimates were sourced from the most recent financial assurance estimates provided by MP Materials.

18.2 Operating Cost Estimates

Operating costs have been forecast based on the mine’s recent actual costs for concentrator, sales, general and administrative costs. For mining, the operating costs were estimated by SRK from a first principles basis. For crushing, concentrator and site general and administrative, SRK compared forecast operating costs to the historical cost data and believes the forecasts represent a reasonable outlook for the operation. For the separations facility, SGS and MP Materials estimated the operating costs based on a first principles build-up.

As with capital costs, operating costs are captured in US dollars and are estimated at a pre-feasibility level with an accuracy of approximately +/- 25%.

18.2.1 Mining Operating Cost

SRK estimated the required mining equipment fleet, required production operating hours, and manpower to arrive at an estimate of the mining costs that the mining operations would incur. The mining costs were developed from first principles and compared to recent actual costs. The mining operating costs are presented in the following categories:

• Drilling (contractor)

• Blasting (contractor)

• Loading

• Hauling

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• Other Mine Operations (dozing, grading, road maintenance operations, etc.)

• Support Equipment Operations (equipment fueling, pit dewatering, pit lighting, etc.)

• Miscellaneous Operations (various support operations, etc.)

• Mine Engineering (mine technical personnel and technical consulting)

• Mine Administration and Supervision (mine and maintenance supervision, etc.)

• Freight (for equipment supplies and parts, excluding freight for fuel)

• Contingency

A maintenance cost was allocated to each category that required equipment maintenance.

The mine operating cost estimate includes all mine functions to deliver material to the dumps, stockpiles, and primary crusher. The mining cost center also includes operating labor for the crusher feed loader and for loading, hauling, and dozing of paste tailings.

A summary of the LoM unit mine operating costs is presented in Table 18-3. The unit mining costs are presented both with and without long-term stockpile tons included in the divisor. “Per short ton mined” refers to the LoM mining cost divided by the number of short tons of ore and waste excavated from the open pit but excluding all re-handled ore. “Per short ton moved” refers to the LoM mining cost divided by the number of short tons of ore and waste excavated from the open pit, but also including all ore re-handled from long term stockpiles, all ore fed to the crusher by front-end-loader, and all fine ore transferred by trucks from the crusher to the mill.

Total LoM mining costs are estimated at US$664 million, with expected unit costs of US$3.26/st-mined and US$2.47/st-moved.

Table 18-3: Mining Operating Costs

LoM Short Tons Mined/Moved (000)			203,872		269,150
Category	US$000		US$/st-Mined		US$/st-Moved
Drilling/Blasting/Loading/Hauling		368,641		1.808		1.370
Other mining costs		204,462		1.003		0.760
Mine engineering and administration		47,257		0.232		0.176
Contingency (7%)		43,425		0.213		0.161
Total		$663,786		$3.26		$2.47

Source: SRK, 2023

Annual mining unit costs and annual material movement are presented in Figure 18-1.

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Source: SRK, 2023

Figure 18-1: Mining Unit Cost Profile

The basis for the mining operating cost estimates includes the following parameters:

• Diesel fuel cost of US$2.92/US gallon (delivered to site)

• Average density for waste of 0.0864 st /ft³ (2.77 t/m³)

• Average density for ore of 0.0976 st /ft³ (3.13 t/m³)

• Average moisture content for rock is 2%

• Average swell factor of mined rock is 40% for loading and hauling estimation

• Typical mining operations support equipment utilization of 1,512 to 3,025 operating hours per year (for track dozer, grader, water trucks, excavator, etc.)

• Rehandling crusher ore feed to the primary crusher from RoM stockpiles

• Estimated average tire lives of:

o Wheel loaders: 4,000 operating hours

o Haul trucks: 4,000 operating hours

o Other major mining equipment: 3,500 operating hours

• 3 to 5% freight cost on mining operating and maintenance supplies

• 7% contingency is included in the mining operating cost estimates

Employee wages (including appropriate overtime allowances) and wage burdens (33%) were based on labor cost information provided by MP Materials. The costs for maintenance supplies and materials were based on estimates presented in the current InfoMine mining cost service publications. Other mining related costs were provided by MP Materials.

Included in the mine operating cost estimate are the following:

• Drilling contractor costs

• Blasting contractor costs

• Equipment and labor costs for ore and waste mining from the pit

• Equipment and labor costs for stockpile rehandling

• Equipment and labor costs for the crusher feed loader

• Equipment and labor costs for loading, hauling, and dozing of paste tailings

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• Contractor and professional services

• Memberships and subscriptions

• Office and building costs

Excluded from the mine operating cost estimate are the following:

• Mining equipment replacements and rebuilds (overhauls) which are included in the mining sustaining capital costs

• Post-mining reclamation costs

• Processing related costs

• General overheads outside of the mine

18.2.2 Processing Operating Cost

Crushing and Concentrating Cost

The forecast average LoM processing cost, inclusive of crushing costs, is US$54.32 per short ton of ore fed to the mill. This cost is based on actual costs incurred by MP Materials during the period January – September 2023.

The processing cost includes:

• Crushing

• Milling, Flotation, Tailings and Lab

• Warehouse

• Engineering

• Utilities

• Facilities,

• Maintenance

• Other Related Costs

Separations Facility Operating Cost

The operating cost estimate for the separations facility (currently ramping up) is based on a first principles estimate developed by SGS and MP Materials. The costs are estimated at a pre-feasibility level with an accuracy of +/- 25%.

The separations cost includes:

• Filtration and Drying

• Calcining

• Leaching, Thickening and Filtration

• Impurity Removal Steps

• Solvent Extraction

• Product Finishing

• Brine Purification and Salt Crystallization

• Water Treatment Plant and Combined Heat and Power Plant costs

• Incremental facilities and utilities expenses

• Incremental maintenance expenses

• Other Related Costs

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Operations and labor were determined by MP Materials’ analysis of staffing needs by circuit, including operations, maintenance, and engineering. A significant proportion of supplies and services costs are reagents, which usage was estimated by MP Materials and SGS as derived from historical operations and records, pilot testing, and 3rd party analysis.

Table 18-4 shows the estimated annual separations facility operating cost when treating 84,148 st of concentrate feed per year. In the economic model, adjustments to the annual separations operating costs were applied based on fixed costs ($25.94 million) and variable costs (US$1,080.59 per st of concentrate) for periods when more or less concentrate is being treated. The fixed cost is factored in the first year of operations to account for a partial operational year.

Table 18-4: Separations Operating Costs

Category	US$000’s/year
Fixed Cost		25,940
Variable Cost		90,929
Total		$116,869

Source: MP Materials / SGS

Note: Based on 84,148 st of concentrate treated.

18.2.3 Selling, General, and Administrative Operating Costs

SRK evaluated site general and administrative (G&A) expenses for the Mountain Pass operation on the basis that any additional G&A costs associated with the separations facility are captured within the operating cost estimate for that facility provided by SGS (as the QP responsible for those costs). Actual G&A costs over the trailing 9 months (January 2021 to September 2021) are shown in Table 18-5.

Table 18-5: Summary of MP Materials Site G&A Operating Costs

G&A Costs	Units		Trailing (9 Month Total
G&A		US$ (000)		15,933

Source: MP Materials, 2023

Given the current inflationary environment, SRK views the most recent costs (i.e., 9 months trailing) as most reflective of the operation’s forward looking costs.

The Mountain Pass mining operation is in steady state and no significant changes are forecast with respect to G&A expenses other than those associated with the addition of the separations facility which are captured within that facilities operating costs and are not accounted for here. In SRK’s opinion, the steady state operation of the asset and lack of forecast significant changes to G&A spend indicate that material changes in G&A spend are unlikely and SRK is therefore comfortable extending this operating cost without modification. This results in G&A costs of US$21.2 million per year, which is treated as fully fixed for modeling purposes. This cost is factored in the first year of operations to account for a partial operational year.

As part of the net revenue calculation in the model, selling (i.e., shipping) costs are calculated separately from G&A costs. The modeled shipping costs are US$180 per metric tonne of product as provided by MP Materials. This is broadly in line with previous realized shipping costs at the operation and the current market environment.

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19 Economic Analysis

19.1 General Description

SRK prepared a cash flow model to evaluate Mountain Pass ore reserves on a real basis. This model was prepared on an annual basis from the reserve effective date to the exhaustion of the reserves. This section presents the main assumptions used in the cash flow model and the resulting indicative economics. The model results are presented in U.S. dollars (US$), unless otherwise stated.

All results are presented in this section on a 100% basis.

As with the capital and operating cost forecasts, the economic analysis is inherently a forward-looking exercise. These estimates rely upon a range of assumptions and forecasts that are subject to change depending upon macroeconomic conditions, operating strategy and new data collected through future operations.

19.2 Basic Model Parameters

Key criteria used in the analysis are presented throughout this section. Basic model parameters are summarized in Table 19-1.

Table 19-1: Basic Model Parameters

Description	Value
TEM Time Zero Start Date	October 1, 2023
Mine Life	34 years (partial first year)
Percentage of Concentrate Fed to the Separations Facility
Q4 2023	20%
2024	61.25%
2025 through 2056	100%
Discount Rate	6%

Source: SRK, MP Materials

All costs incurred prior to the model start date are considered sunk costs. The potential impact of these costs on the economics of the operation is not evaluated. This includes contributions to depreciation and working capital as these items are assumed to have a zero balance at model start.

The selected discount rate is 6% as directed by MP Materials.

19.3 External Factors

19.3.1 Pricing

Modeled prices are based on the prices developed in the Market Studies and Contracts section of this report (Section 16). The prices are modeled as:

• Concentrate – US$10.94/kg contained REO (equivalent to US$6,564 per metric tonne of 60% TREO concentrate)

• Separated PrNd product – US$131.60/kg

• Separated La product – US$1.50/kg

• Separated Ce product – US$2.51/kg

• Separated SEG+ product – US$51.90/kg

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These prices are modeled as a CIF price and shipping costs are applied separately within the model.

All product streams produced by the operation are modeled as being subject to the prices presented above.

Shipping costs are modeled at US$180.00 per metric tonne of material for both concentrate and separated material. A 13% VAT tax and 2.5% commission are applied to concentrate sold to outside parties to account product taxes and selling costs for concentrate per MP Materials. VAT and commission are applied in the model for material processed through the separations plant.

19.3.2 Taxes and Royalties

As modeled, the operation is subject to a combined 26.84% (federal and state) income tax rate. This rate reflects reductions in tax rates resulting from depletion. This approach was recommended by MP Materials for modelling purposes. All expended capital is subject to depreciation over an 8 year period. Depreciation occurs via straight line method. No existing depreciation pools are accounted for in the model.

SRK notes that the project is being evaluated as a standalone entity for this exercise (without a corporate structure). As such, tax calculations presented here may differ significantly from actuals incurred by MP Materials.

19.3.3 Working Capital

The assumptions used for working capital in this analysis are as follows:

• Accounts Receivable (A/R): 30 day delay

• Accounts Payable (A/P): 30 day delay

• Zero opening balance for A/R and A/P

19.4 Technical Factors

19.4.1 Mining Profile

The modeled mining profile was developed by SRK. The details of the mining profile are presented previously in this report. No modifications were made to the profile for use in the economic model. The modeled profile is presented on a 100% basis in Figure 19-1.

Source: SRK

Figure 19-1: Mining Profile

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A summary of the modeled life of mine mining profile is presented in Table 19-2.

Table 19-2: LoM Mining Summary

Description	Units	Value
Total Ore Mined	dst (million)		28.08
Initial Stockpiles	dst (million)		0.61
Total Waste Mined	dst (million)		175.79
Total Material Mined	dst (million)		204.78
Average Grade (Mill Feed) LoM Strip Ratio	%TREO Num#		6.22 6.3 x	%

Source: SRK

19.4.2 Processing Profile

The concentrator processing profile was developed by SRK and results from the application of stockpile and binning logic to the mining profile external to the economic model. No modifications were made to the profile for use in the economic model other than for sensitivity analysis.

A summary of the modeled life of mine processing profile is presented in Table 19-3.

Table 19-3: LoM Processing Profile

Description	Units	Value
LoM Ore Processed Average Feed Grade Concentrate Grade Target	dst (million) % TREO % TREO		28.69 6.22% 60.00%
Concentrate Moisture LoM Concentrate Produced Avg Annual Concentrate Produced	% dmt (million) wmt		9.00% 1.71 55,176

Source: SRK

The production profile was developed by SRK and results from the application of processing logic to the processing profile external to the economic model. No modifications were made to the profile for use in the economic model other than for sensitivity analysis. The modeled profile for concentrate production is presented in Figure 19-2 and the resulting separated product profile is presented in Figure 19-3.

As the separations facility continues to ramp up, the product from the concentrator will be fed to the separations facility to produce separated materials for sale as per the descriptions contained within this report. It is expected that the separations facility will operate at 20% of its capacity in Q4 2023, 61.25% of its capacity in 2024, and 100% of its capacity from 2025 onward. When the separations facility is operating at 100% capacity, it is assumed that it will consume all of the concentrate that is produced on site.

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Source: SRK

Figure 19-2: Concentrate Production

Source: SRK

Note: The costs are higher for 2023 because the processing facilities operate for only three months and the separations plant is not at full capacity.

Figure 19-3: Separations Production Profile

19.4.3 Operating Costs

Operating costs modeled in US dollars and can be categorized as mining, processing and site G&A costs. No contingency amounts have been added to the operating costs within the financial model; however, the mining costs were imported from a first principles cost buildup that included 7% contingency. A summary of the operating costs over the life of the operation is presented in Figure 19-4.

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Source: SRK

Figure 19-4: Annual Operating Costs

The contributions of the different operating cost segments over the life of the operation are presented in Figure 19-5.

Source: SRK

Figure 19-5: LoM Operating Costs

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19.4.4 Mining

The mining cost profile was developed external to the model and was imported into the model as a fixed cost on an annual basis. The result of this approach is presented in Table 19-4.

Table 19-4: Mining Cost Summary

LoM Mining Costs	Units	Value
Mining Costs	US$ (million)		663.8
Mining Cost	US$/st mined		3.26

Source: SRK

19.4.5 Processing

Processing costs were incorporated into the model as variable costs for the concentrator and a combination of fixed and variable costs for the separations facility. Variable concentrator costs are applied to the tonnage processed through the concentrator. Fixed costs for the separations facility were applied on an annual basis and variable costs are applied on a per ton of feed basis. Table 19-5 presents the cost on a per ton basis for the combined plants.

Table 19-5: Processing Cost Summary

LoM Processing Costs	Units	Value
Processing Costs	US$ (million)		4,401.4
Processing Cost	US$/st processed		153.41

Source: SRK

19.4.6 G&A Costs

Site G&A costs were incorporated into the model as annual fixed costs as presented in Table 19-6.

Table 19-6: G&A Cost Summary

LoM G&A Costs	Units	Value
G&A Costs	US$ (million)		706.4
G&A Cost	US$/st processed		24.62

Source: SRK

19.4.7 Capital Costs

As the operation is an existing mine, no initial capital has been modeled. Capital is modeled on an annual basis and is used in the model as developed in previous sections. No contingency amounts have been added to the sustaining capital within the model. Closure costs are modeled as capital and are captured as a one-time payment the year following cessation of operations. The modeled capital profile is presented in Figure 19-6.

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Source: SRK

Figure 19-6: Capital Expenditure Profile

19.4.8 Results

The economic analysis metrics are prepared on annual after-tax basis in 2023 US$. The results of the analysis are presented in Table 19-7. The results indicate that, at modeled prices, the operation returns a pre-tax NPV at 6% of US$7.0 billion and an after-tax NPV at 6% of US$5.2 billion. Note that because the mine is in operation and is valued on a total project basis with prior costs treated as sunk, IRR and payback period analysis are not relevant metrics. Annual project after tax cash flow is presented in Figure 19-7.

Source: SRK

Figure 19-7: Annual Cash Flow

Table 19-7: Economic Result

LoM Cash Flow (unfinanced)	Units	Value
Total Revenue	US$ (Million)		20,040
Total Opex	US$ (Million)		(5,772)
Operating Margin	US$ (Million)		14,268
Operating Margin Ratio	%		71%
Taxes Paid	US$ (Million)		(3,638)
Before Tax
Free Cash Flow	US$ (Million)		13,413
NPV at 6%	US$ (Million)		6,998
After Tax
Free Cash Flow	US$ (Million)		9,775
NPV at 6%	US$ (Million)		5,193

Source: SRK

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19.4.9 Sensitivity Analysis

SRK performed a sensitivity analysis to determine the relative sensitivity of the operation’s after-tax NPV to a number of key parameters (Figure 19-8). This is accomplished by flexing each parameter upwards and downwards by 10%. Within the constraints of this analysis, the operation appears to be most sensitive to mined grades, commodity prices and recovery or mass yield assumptions within the processing plant. SRK cautions that this sensitivity analysis is for information only and notes that these parameters were flexed in isolation within the model and are assumed to be uncorrelated with one another which may not be reflective of reality. Additionally, the amount of flex in the selected parameters may violate physical or environmental constraints present at the operation.

Source: SRK

Note: Parameters flexed upwards and downwards by 10%.

Figure 19-8: After-Tax Sensitivity Analysis

19.4.10  Physical and Cash Flow Snapshot

 The annual cashflow, expressed in million U.S. dollars, is presented in Figure 19-9.

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Source: SRK

Note: 2023 is a partial year covering October 1^st through December 31^st.

Figure 19-9: Mountain Pass Annual Physicals and Cashflow (US$ millions)

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20  Adjacent Properties

The Mojave National Preserve is located to the north and southwest of the Mountain Pass property. The U.S. Bureau of Land Management and National Park Service administer the National Preserve as well as other public lands surrounding the property. SRK is not aware of any other active mining properties in the vicinity of Mountain Pass.

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21  Other Relevant Data and Information

There is no additional relevant data or information that would be material to the mineral resources or reserves at the Mountain Pass Project, beyond what is discussed in the other sections of this report.

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22 Interpretation and Conclusions

Based on the data available and the analysis described in this report, in SRK’s opinion, the Mountain Pass operation has a valid resource and reserve, as stated herein.

22.1 Mineral Resource Estimate

The mineral resource estimate is constrained by a geological model and grade boundaries internal to the carbonatite shapes which define a higher grade TREO-rich core vs. an undifferentiated outer shell. The project features a simple Excel-based drilling “database”, most of which has no quality control. SRK supervised a historical drill core re-sampling and re-assaying program in 2009 through 2010 which demonstrated that, historically, the Mountain Pass laboratory underestimated grade. This is supported further by the fact that grade control and production grades are higher than predicted by the resource block model. The mine currently features positive reconciliations to previous modeling efforts as well as the current prediction of grade if based solely on exploration data. Consequently, SRK is confident that the resource block model is based on drilling data which has been demonstrated to be reliable, albeit conservative, representation of the TREO grade. Other elements such as phosphorus or the discrete LREO or HREO components have been variably analyzed and do not exist at the same density as the TREO information.

SRK has constrained and controlled the mineral resource estimation as a function of a robust geological model based on updated information collected as recently as 2020. TREO samples from drilling and blastholes have been composited for the purposes of use in estimation. Estimates of grade from both data sets have been made into a conventional block model, coded by lithology, resource domain, and a variety of other factors relevant to mining and reporting.

The block model has been constrained by a resource pit shell and reported above the reported cut-off grade. Mineral resources have been reported in this report both inclusive of reserves, and exclusive of reserves. The latter should be considered final and authoritative for SEC disclosure purposes.

SRK has addressed uncertainty and risk in the estimate by categorizing the mineral resources with respect to confidence in the estimate or underlying data supporting it. The mineral resources at the Mountain Pass deposit have been classified in accordance with SEC S-K 1300 definitions and guidance. The classification parameters are defined by both the distance to composite data, the number of drillholes used to inform block grades and a geostatistical indicator of relative estimation quality (kriging efficiency).

22.2 Mineral Reserve Estimate

SRK developed a life-of-mine (LoM) plan for the Mountain Pass operation in support of mineral reserves. MP Materials will operate an on-site separations facility at the Mountain Pass site that will allow the Company to separate bastnaesite concentrate into four individual REO products for sale (PrNd oxide, SEG oxalate, La carbonate/La oxide, and Ce chloride). For economic modeling purposes, a combination of concentrate sales and separated product sales was assumed for Q4 2023 through Q4 2024 while the separations facility ramps up to full capacity. From 2025 onward, it was assumed that all concentrate will be fed to the separations facility. Forecast economic parameters are based on current cost performance for process, transportation, and administrative costs, as well as a first

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principles estimation of future mining costs. Forecast revenue from concentrate sales and individual separated product sales is based on a preliminary market study commissioned by MP Materials.

From this evaluation, pit optimization was performed based on an equivalent concentrate price of US$ 10,836 per dry st of 60% TREO concentrate. The results of pit optimization guided the design and scheduling of the ultimate pit. SRK generated a cash flow model which indicated positive economics for the LoM plan, which provides the basis for the reserves. Reserves within the new ultimate pit are sequenced for the full 34-year LoM (Q4 2023 through 2056).

The costs used for pit optimization include estimated mining, processing, sustaining capital, transportation, and administrative costs, including an allocation of corporate costs.

Processing recovery for concentrate is variable based on a mathematical relationship to estimate overall TREO recovery versus ore grade. The calculated COG for the reserves is 2.43% TREO, which was applied to indicated blocks contained within an ultimate pit, the design of which was guided by economic pit optimization.

The optimized pit shell selected to guide final pit design was based on a combination of the revenue factor (RF) 0.70 pit (used on the north half of the deposit) and the RF 1.00 pit shell (used on the south half of the deposit). The IRA pit slope angles used for the mine design are based on operational-level geotechnical studies and range from 44° to 47°.

Measured resources in stockpiles were converted to proven reserves. Indicated pit resources were converted to probable reserves by applying the appropriate modifying factors, as described herein, to potential mining pit shapes created during the mine design process. Inferred resources present within the LoM pit are treated as waste.

The mine design process results in in situ open pit probable mining reserves of 28.1 million st with an average grade of 6.26% TREO. Additionally, there are 0.6 million st of proven mineral reserves in stockpiles with an average grade of 4.33% TREO. The reference point for the mineral reserves is ore delivered to the Mountain Pass concentrator.

In the opinion of SRK as the QP, the conversion of mineral resources to mineral reserves has been completed in accordance with CFR 17, Part 229 (S-K 1300).

The reserve estimate herein is subject to potential change based on changes to the forward-looking cost and revenue assumptions utilized in this study. It is assumed that MP Materials will ramp up its on-site separations facilities to full capacity by the end of 2024. For economic modeling purposes, a combination of concentrate sales and separated product sales was assumed for Q4 2023 through Q4 2024. From 2025 onward, it was assumed that all concentrate will be fed to the separations facility.

Full extraction of this reserve is dependent upon modification of current permitted boundaries for the open pit. Failure to achieve modification of these boundaries would result in MP Materials not being able to extract the full reserve estimated in this study. It is MP Materials’ expectation that it will be successful in modifying this permit condition. In SRK’s opinion, MP Materials’ expectation in this regard is reasonable.

A portion of the resource pit encroaches on an adjoining mineral right holder’s concession. This portion of the pit would only include waste stripping (i.e., no rare earth mineralization is assumed to be extracted from this concession). The prior owner of Mountain Pass had an agreement with this concession holder to allow this waste stripping (with the requirement that aggregate mined be

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stockpiled for the owner’s use). MP Materials does not currently have this agreement in place, but SRK believes it is reasonable to assume MP Materials will be able to negotiate a similar agreement.

22.3 Metallurgy and Processing

22.3.1 Existing Crushing and Concentration Operations

• MP Materials has operated a flotation concentrator since December 2017 to recover a bastnaesite concentrate that is currently shipped to China for further processing.

• MP Materials has conducted flotation studies to evaluate TREO recovery versus ore grade and has developed a mathematical relationship to estimate overall TREO recovery versus ore grade, which has been used to estimate TREO recovery from lower grade ores later in the mine life.

• Significant improvements in concentrator performance have occurred since May 2019, which are attributed primarily to the installation of a boiler that has enabled flotation to be conducted at a constant higher temperature, as well as new reagent testing and blending of historically problematic ores.

• During 2022 TREO recovery averaged 65.3% into concentrates containing an average of 61.3% TREO.

• During 2023 (January - September) TREO recovery has averaged 64.0% into concentrates averaging 61.9% TREO.

22.3.2 Modified and Recommissioned Separations Facility

MP Materials is in the process of ramping up its modified and recommissioned on-site separations facility to produce individual rare earth products. The incentive for this substantial process change is the enhancement of revenue that will be realized for producing individual rare earth products as compared to the previous practice of producing a single rare earth containing flotation concentrate which was sold to various entities that separate and market individual rare earth products. Over the past several years, MP Materials has made substantial technical and financial commitments to modify and recommission an on-site separation facility that will allow for the sale of individual rare earth products.

Consequently, based upon the project documentation provided, a site visit to the MP Materials installations at Mountain Pass, and conversations with MP Materials engineers who are directly involved with the ongoing ramp up operations, it is the opinion of SGS that the Mountain Pass modification and modernization project has been performed in a professional manner. It is SGS’s further opinion that the ramp up schedule assumed for economic modeling purposes, which estimated feeding 20% and 61.25% of concentrate production into the facility in Q4 2023 and full year 2024, respectively, is likely to be achieved. From 2025 onward, the separations facility is likely to operate at full capacity thereby consuming all or nearly all of the bastnaesite flotation concentrate produced on site.

22.4 Project Infrastructure

The Mountain Pass site has all facilities required for operation, including the open pit, concentrator, separations facility, access and haul roads, explosives storage, fuel tanks and fueling systems, warehouse, security guard house and perimeter fencing, tailings filter plant, tailings storage area, waste rock storage area, administrative and office buildings, surface water control systems, evaporation ponds, miscellaneous shops, truck shop, laboratory, multiple laydown areas, power

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supply, water supply, waste handling bins and temporary storage locations, and a fully developed communications system.

Access to the site, as well as site haul roads and other minor roads are fully developed and controlled by MP Materials. There is no public access through the Project area. All public access roads that lead to the Project are gated at the property boundary.

Outside services include industrial maintenance contractors, equipment suppliers and general service contractors. Access to qualified contractors and suppliers is excellent due to the proximity of population centers such as Las Vegas, Nevada as well as Elko, Nevada (an established large mining district) and Phoenix, Arizona (servicing the copper mining industry).

Substantially all the power to the Mountain Pass facility is currently supplied by a Combined Heat and Power (CHP) or co-generation (cogen) power facility with two natural gas-fired turbines capable of producing up to 26 MW of power combined. In addition, the site is served by a 12-kV line from a Southern California Edison substation two miles away.

Water is supplied through active water wells located eight miles west of the project. Fire systems are supplied by separate fire water tanks and pumps.

The LoM plan will require the relocation in 2035 of the paste tailings plant and the water tanks currently northeast of the pit highwall near the concentration plant. Additionally, the crusher will be relocated in 2028 to allow the pit to expand to the north. Capital cost provisions are included in the economic model for these relocations.

The design capacity of the tailings storage facility is approximately 24 million st. The project has utilized approximately 4.2 million st of that space. The existing facility will have a remaining capacity of approximately 19.8 million st which will provide approximately 24 years of storage. MP Materials will expand the existing tailings facility to the northwest in approximately 2047 to provide an additional 9 years of storage capacity.

Site logistics are straightforward with the concentrate product shipped in supersacks within a shipping container by truck to the port of Los Angeles. At the port, the containers are loaded onto a container ship and shipped to the final customers. Refined products for domestic customers are shipped in supersacks and intermediate bulk containers (IBC tote).

22.5 Products and Markets

Separated REE products outlined in this report (PrNd oxide, SEG+ oxalate, La carbonate, and Ce chloride) are considered marketable from an economic perspective, provided market standards and requirements are met. Adamas forecasts a long-term price of US$131.6/kg REO for PrNd oxide, US$51.9/kg REO for SEG+ oxalate, US$1.5/kg REO for Lanthanum carbonate, and US$2.51/kg REO for Cerium chloride. The mixed rare earth concentrate price of US$10.94/kg of contained REO will be principally driven by trends in PrNd and dysprosium, price swings of which will be mirrored by concentrates.

22.6 Environmental, Closure, and Permitting

As of September 30, 2023, MP Materials holds the necessary operating permits, including conditional use and minor use permits from the County of San Bernardino (SBC), which currently allows continued operations of the Mountain Pass facility through 2042. The proposed mine plan extends the mine life

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to 2056. The future mine plan requires expansion of the current permitted boundary of the open pit, expansion of the North Overburden Stockpile and construction of a new East Overburden Stockpile.

MP Materials will need to engage with the SBC-LUS and other regulatory authorities and allow sufficient time to prepare the permit applications and gain the necessary approvals to implement the mine plan described herein. There is a risk that the timing for regulatory approvals may be longer than anticipated. In this case, MP Materials may not be able to implement or follow the mine plan as currently proposed. SRK is of the opinion that MP Materials will continue to successfully engage regulatory authorities and gain approval for future amendments related to site operations within the private property boundary.

22.7 Projected Economic Outcomes

The Mountain Pass operation consists of an open pit mine and several processing facilities fed by the open pit mine. The operation is expected to have a 34 year life with the first modeled year of operation a partial year to align with the effective date of the reserves. Under the forward-looking assumptions modeled and documented in this report, the operation is forecast to generate positive cashflow. As modeled for this analysis, the operation is forecast to produce 1.71 million dry metric tonnes of concentrate to be either sold or processed into separated materials. This results in a forecast after-tax project NPV at 6% of US$5.2 billion.

The analysis performed for this report indicates that the operation’s NPV is most sensitive to variations in the grade of ore mined, the commodity price received and processing plant performance.

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23 Recommendations

As an operating mine, there are no further work programs or studies that are required to extract the reserve estimated herein. However, there remain opportunities for MP Materials to perform additional data collection or study to potentially benefit the operation.

23.1 Geology and Resources

SRK notes that ongoing infill and exploration drilling is recommended for further development of the Mountain Pass mine. As shown in recent production reconciliation, modeling of short-range variability in the resource will depend on additional information at relatively close spacings to characterize and improve prediction of tons and grade for short term planning. Such a program would involve continuous drilling of immediate near-term production and should be considered an operational cost of the mine in the future. In addition, the resource locally remains open at depth and may benefit from additional drilling in more widely-spaced areas. SRK estimates a drilling program of 10,000 to 20,000 ft of drilling would improve confidence in the model and potentially convert existing Inferred resources to a higher category appropriate for conversion to reserves.

Additional recommendations include:

• Update of the geological and resource model based on data collected onsite since the previous update in 2020.

• Refinement of the existing structural model with additional data and mapping collected by structural geologists or rock mechanics experts to support the geological model and

• A study of ore density versus ore grade, which can be completed using existing core in storage, could improve the accuracy of the block model grade and tonnage estimation.

• Improved database architecture and validation of exploration and mine data. Currently, this is based almost entirely on digital spreadsheets.

• Separate assaying of the light rare earth oxides and phosphorus through the carbonatite units and 20 ft into the hangingwall and footwall units should be implemented routinely for future drilling and further re-assaying of existing drill core. This should be extended to individual heavy rare earth oxides should the project strategy consider incorporating these as products in the future.

• Phosphorus assays may help to refine the resource model by identifying monazite-rich zones. SRK also recommends creating a minimum of two (a high and low grade) site specific reference standards for QA/QC to be used in all future assaying programs. These reference standards should be certified through a multi-laboratory round-robin program to achieve industry best practice.

• SRK strongly recommends improving the QA/QC process to demonstrate that the internal laboratory and any external laboratories can be independently checked for precision and accuracy. Currently, the lack of commercial standards and a consistent approach to blank and duplicate insertion and analysis is not consistent with industry standards.

The estimated cost for the additional drilling and other recommendations is approximately US$3 million.

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23.2 Mining and Reserves

23.2.1 Geotechnical Recommendations:

• Routine geotechnical slope monitoring, data collection, and analysis should continue. MP Materials should review geotechnical parameters and optimize the mine plan prior to starting new phases based on this review. This is an ongoing effort at Mountain Pass and costs are part of the mine operating costs that have been estimated for extraction of the mineral reserves.

23.2.2 Hydrogeology:

• Conduct additional hydrogeological studies of the deep part of the bedrock to the elevation of the proposed bottom of the pit (3,000 ft amsl) by conducting packer isolated tests in three or four core holes defining bedrock permeability and dewatering targets (where and to what depth dewatering wells can be installed). Vibrated wire piezometers (similarly installed by CNI) are also recommended in these core holes).

• Develop numerical groundwater flow to predict inflow to the proposed pit and better define:

o Dewatering requirements

o Pore-pressures in pit walls and the potential necessity to reduce them by installation of horizontal drain holes from pit benches (if required by geotechnical conditions of the slopes)

o Propagation of the drawdown cone during both mining and post-mining conditions (including pit lake infilling) to evaluate potential impact the groundwater system as a result of continued deepening of the open pit.

• The estimated cost to conduct the recommended hydrogeological studies and numerical groundwater modeling is approximately US$920,000.

23.2.3 Costs and Economics

• Develop a more-detailed mid- and long-term sustaining capital expenditure estimate. SRK completed a long-term estimate for mining-related capital, and other components of the operation should generate a similar forecast to improve long-term budgeting. There would be no additional cost for this recommendation as the work would be performed by existing MP Materials staff.

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24 References

American Geological Institute (AGI) (1997). Dictionary of Mining, Mineral, and Related Terms, 2^nd Ed.

Bieniawski, Z.T. (1976). Rock Mass Classification in Rock Engineering, in proceedings Symposium on Exploration for Rock Engineering, Johannesburg, South Africa, vol 1, p. 97-106.

Call & Nicholas Inc. (CNI) (2011). Slope Stability Study Mountain Pass Mine. Consultant’s report dated October 2011, 135 p.

Call & Nicholas Inc. (CNI) (2021) November 2021 Mountain Pass: power point presentation showing status of geotechnical study, November 2021

Castor, S.B. (2008). The Mountain Pass Rare-Earth Carbonatite and Associated Ultrapotassic Rocks, California. The Canadian Mineralogist, 46 (4): 779-806.

CNI (2022). 2022 Hydrogeological Characterization Study: memo prepared for MP Minerals, November 3, 2022.

CNI (2022). Mountain Pass Phase 10 Geotechnical Feasibility Study, January 2022.

ENSR (1996). Molycorp Mountain Pass Mine Expansion Project Mountain Pass, California. Draft Environmental Impact Report, December 9.

Geo-Logic Associates (2023). First Semiannual 2023 Monitoring Report, Mountain Pass Mine and Mill Site, San Bernardino County, California. July 30, 2023.

Geo-Logic Associates (2021), First Semiannual 2021 Monitoring Report Mine and Mill Site Monitoring and Reporting Program: report prepared for MP Materials, July 30, 2021

Geo-Logic Associates (2021). Annual 2022 Monitoring Report Mine and Mill Site Monitoring and Reporting Program: report prepared for MP Materials, March 30, 2021.

Geomega, Inc. (2000). A Groundwater Hydrology and Modeling Investigation of the Molycorp Mountain Pass Mine and Mill Site, Mountain Pass, California. February 2020.

Golder Associates (2002). Post Closure Stability Analyses, Mountain Pass Mine, California. Consultant’s Technical Memorandum dated November 5, 2002, 24 p.

Golder Associates (2009). Mountain Pass Mine Pit Slope Inspection. Consultant’s Report dated September 8, 2009, 50 p.

GSi/Water (1995). Results of Falling Head Tests in Selected Monitoring Wells, Mountain Pass Operations, Mountain Pass, California. January 1995.

GSi/Water (1991). Ground Water Cleanup Strategy for Molycorp, Inc. Mountain Pass Operations. 1991.

Haxel, G.B. (2005). Ultrapotassic Mafic Dikes and Rare Earth Element- and Barium-Rich Carbonatite at Mountain Pass, Mojave Desert, Southern California: Summary and Field Trip Localities. U.S. Geological Survey, Open-File Report 2005-1219.

InfoMine USA, Inc., (2023). Mine and Mill Equipment Costs, Spokane Valley, Washington.

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Olson, J.C., Shawe, D.R., Pray, L.C., and Sharp, W.N., 1954. Rare-Earth Mineral Deposits of the Mountain Pass District, San Bernardino County, California, U.S. Geological Survey, Geological Survey Professional Paper 261.

Molycorp Inc. (2005). Final Mine and Reclamation Plan for the Mountain Pass Mine, 2004M-02, CA Mine Id#91-36-0002, Submitted to County of San Bernadino, Finalized March 2005, 117p.

Nicholas & Sims, 2001, Collecting and Using Geologic Structure for Slope Design. Published in “Slope Stability in Surface Mining” ed Hustrulid, W.A., McCarter, M.K., & VanZyl D.: pp 11-26.

Read & Stacey (2009). Guidelines for Open Pit Slope Design, CRC Press, 510 p.

Ritchie, AM (1963). Evaluation of Rockfall and Its Control, Highway Research Record (17) 13-28.

Ryan & Pryor (2000). Designing Catch Benches and Interramp Slopes. In W. A. Hustrulid, M. K. McCarter, & D. J. Van Zyl (Eds.), Slope Stability in Surface Mining (pp. 27-38). Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc.

SRK Consulting (2022). SEC Technical Report Summary Pre-Feasibility Study Mountain Pass Mine, San Bernardino County, California, dated February 16, 2022.

SRK Consulting (2020). SEC Guide 7 Technical Report Resource and Reserve Statement, Mountain Pass, San Bernadino County, California, dated September 28, 2020, 214p.

SRK Consulting (2012). NI 43-101 Technical Report Mountain Pass Rare Earth Project, San Bernadino County, California, dated May 7, 2012, 251p.

SRK (2010), Engineering Study for Re-Start of Mountain Pass Rare Earth Element Mine and Processing Facility Mountain Pass, California: report prepared for Molycorp Minerals, April 28.

SRK (1985). Hydrologic Assessment Report Prepared for the Application for Exemption from the Toxic Pits Cleanup Act of 1984 (AB 3566), Molycorp Mountain Pass Operations. December 1985.

Storey, A.W. (2010). Design Optimization of Safety Benches for Surface Quarries through Rockfall Testing and Evaluation, MS Thesis, Virginia Tech, Blacksburg, VA, 136p.

Vector Engineering Inc. (1995). Post Closure Pit Slope Analyses for the Mountain Pass Mine in San Bernadino County, California, Job No. 975003.00. December, 1995

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25 Reliance on Information Provided by the Registrant

The Qualified Person’s opinions contained herein is based on information provided to the Qualified Persons by MP Materials throughout the course of the investigations. Table 25-1 of this section of the Technical Report Summary will:

(i) Identify the categories of information provided by the registrant;

(ii) Identify the particular portions of the Technical Report Summary that were prepared in reliance on information provided by the registrant pursuant to Subpart 1302 (f)(1), and the extent of that reliance; and

(iii) Disclose why the qualified person considers it reasonable to rely upon the registrant for any of the information specified in Subpart 1302 (f)(1).

Table 25-1: Reliance on Information Provided by the Registrant

Category	Report  Item/  Portion	Portion of  Technical Report  Summary	Disclose Why the Qualified Person Considers it Reasonable to Rely Upon the Registrant
Claims List	3	3.2 Mineral Title	MP Materials provided SRK with a current listing of claims. The information was sourced from the Bureau of Land Management.
Marketing Agreements	16	16.5 Specific  Products	MP Materials provided Adamas with information regarding the product specifications intended for production both now and in future
Marketing Agreements	16	16.7 Contracts	MP Materials provided Adamas with current marketing agreements and potential terms of agreements tied to future product sales and operations.
Marketing Plans	19	19 Economic  Analysis	MP Materials provided SRK with input into the shipping points of sale and associated shipping costs used in the model.
Environmental Studies	17	17.1  Environmental  Studies	SRK was provided with various environmental studies conducted on site. These studies were of a vintage that independent validation could not be completed.
Discount Rates	19	19 Economic  Analysis	MP Materials provided SRK with discount rates for project evaluation in line with previous evaluations.
Tax rates and government royalties	19	19 Economic  Analysis	SRK was provided with income and applicable VAT tax rates by MP Materials for application within the model. These rates are in line with SRK’s understanding of the tax regime at the project location.

Source: SRK and Adamas

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Signature Page

This report titled “SEC Technical Report Summary, Pre-Feasibility Study, Mountain Pass Mine, San Bernardino County, California” with an effective date of October 1, 2023, was prepared and signed by:

SRK Consulting (U.S.) Inc.	(Signed) SRK Consulting (U.S.) Inc.
Dated at Denver, Colorado
February 22, 2024
SGS North America Inc.	(Signed) SGS North America Inc.
Dated at Tucson, Arizona
February 22, 2024
Adamas Intelligence Inc.	(Signed) Adamas Intelligence Inc.
Dated at Toronto, Canada
February 22, 2024

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Appendices

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Appendix A: Claims List

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Date and Time Run: 10/4/2023 7:34:03 PM Page 1 of 1 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS MINING CLAIM CUSTOMER INFORMATION Admin State: CA Geo State: CA Claimant: MP MINE OPERATIONS LLC Street: HC 1 BOX 224 City: MOUNTAIN PASSS State: CA Postal Code: 92366 Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name County Case Disposition Claim Type Interest Relationship CA101304758 CA101304758 CAMC259387 CAMC259387 JACK 66 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101334324 CA101334324 CAMC51761 CAMC51692 JACK NO 39 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101347323 CA101347323 CAMC70768 CAMC70767 ACE #2 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101348437 CA101348437 CAMC70767 CAMC70767 ACE #1 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101349790 CA101349790 CAMC70769 CAMC70767 ACE #3 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101452381 CA101452381 CAMC273770 CAMC273769 ACE NO 6 SAN BERNARDINO FILED MILL SITE CLAIMANT CA101452742 CA101452742 CAMC263510 CAMC263510 QUEEN 90 SAN BERNARDINO FILED MILL SITE CLAIMANT CA101547491 CA101547491 CAMC51760 CAMC51692 JACK NO 36 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101600622 CA101600622 CAMC153273 CAMC153272 SHADOW VLY 1857 #2 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT CA101759245 CA101759245 CAMC273769 CAMC273769 ACE NO 7 SAN BERNARDINO FILED MILL SITE CLAIMANT CA101759479 CA101759479 CAMC153272 CAMC153272 SHADOW VLY1857 #1 SAN BERNARDINO ACTIVE MILL SITE CLAIMANT NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

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SRK Consulting (U.S.), Inc. SEC Technical Report Summary - Mountain Pass Mine Appendices Date and Time Run: 10/4/2023 7:29:38 PM DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS MENENG CLAIM CUSTOMER INFORMATION Admin State: CA Geo State: CA Claimant: SECURE NATURAL RESOURCES LLC Street: 900 N MICHIGAN AVE STE 1340 City: CHICAGO State: IL Postal Code: 60611-6542 Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101300112 CA101300112 CAMC16271 CAMC16264 MINERAL HILL NO 8 ACTIVE LODE CLAIM 9/3/2024 CA101300164 CA101300164 CAMC233783 CAMC233774 SYENITE 185A ACTIVE LODE CLAIM 9/3/2024 CA101300349 CA101300349 CAMC51743 CAMC51692 EARL NO 5 ACTIVE LODE CLAIM 9/3/2024 CA101300353 CA101300353 CAMC5950 CAMC5840 SYENITE 114 ACTIVE LODE CLAIM 9/3/2024 CA101300355 CA101300355 CAMC5889 CAMC5840 SYENITE 50 ACTIVE LODE CLAIM 9/3/2024 CA101300382 CA101300382 CAMC5872 CAMC5840 SYENITE 33 ACTIVE LODE CLAIM 9/3/2024 CA101300397 CA101300397 CAMC234432 CAMC234416 SYENITE 210 ACTIVE LODE CLAIM 9/3/2024 CA101300466 CA101300466 CAMC5900 CAMC5840 SYENITE 61 ACTIVE LODE CLAIM 9/3/2024 CA101300737 CA101300737 CAMC234453 CAMC234416 SYENITE 231 ACTIVE LODE CLAIM 9/3/2024 CA101300754 CA101300754 CAMC6000 CAMC5840 SYENITE 165 ACTIVE LODE CLAIM 9/3/2024 CA101300927 CA101300927 CAMC244770 CAMC244736 CMF 35 ACTIVE LODE CLAIM 9/3/2024 CA101301524 CA101301524 CAMC5994 CAMC5840 SYENITE 159 ACTIVE LODE CLAIM 9/3/2024 CA101301536 CA101301536 CAMC234454 CAMC234416 SYENITE 232 ACTIVE LODE CLAIM 9/3/2024 CA101302125 CA101302125 CAMC5895 CAMC5840 SYENITE 56 ACTIVE LODE CLAIM 9/3/2024 CA101302176 CA101302176 CAMC201788 CAMC201787 SYENITE 90 ACTIVE LODE CLAIM 9/3/2024 CA101302380 CA101302380 CAMC177649 CAMC177640 SOUTH SYENITE 10 ACTIVE LODE CLAIM 9/3/2024 CA101302391 CA101302391 CAMC5978 CAMC5840 SYENITE 142 ACTIVE LODE CLAIM 9/3/2024 CA101302697 CA101302697 CAMC5917 CAMC5840 SYENITE 78 ACTIVE LODE CLAIM 9/3/2024 CA101302706 CA101302706 CAMC5871 CAMC5840 SYENITE 32 ACTIVE LODE CLAIM 9/3/2024 CA101302962 CA101302962 CAMC244790 CAMC244736 CMF 55 ACTIVE LODE CLAIM 9/3/2024 CA101302967 CA101302967 CAMC5892 CAMC5840 SYENITE 53 ACTIVE LODE CLAIM 9/3/2024

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Date and Time Run: 10/4/2023 7:29:38 PM Page 2 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101303517 CA101303517 CAMC5842 CAMC5840 SYENITE 3 ACTIVE LODE CLAIM 9/3/2024 CA101303524 CA101303524 CAMC47650 CAMC47621 BAILEY 30 ACTIVE LODE CLAIM 9/3/2024 CA101303534 CA101303534 CAMC245119 CAMC245118 SOUTH SYENITE 108 ACTIVE LODE CLAIM 9/3/2024 CA101303907 CA101303907 CAMC5947 CAMC5840 SYENITE 111 ACTIVE LODE CLAIM 9/3/2024 CA101303917 CA101303917 CAMC233775 CAMC233774 SYENITE 146A ACTIVE LODE CLAIM 9/3/2024 CA101304196 CA101304196 CAMC51739 CAMC51692 EARL NO 1 ACTIVE LODE CLAIM 9/3/2024 CA101304375 CA101304375 CAMC5862 CAMC5840 SYENITE 23 ACTIVE LODE CLAIM 9/3/2024 CA101304648 CA101304648 CAMC5858 CAMC5840 SYENITE 19 ACTIVE LODE CLAIM 9/3/2024 CA101304759 CA101304759 CAMC5951 CAMC5840 SYENITE 115 ACTIVE LODE CLAIM 9/3/2024 CA101304800 CA101304800 CAMC5901 CAMC5840 SYENITE 62 ACTIVE LODE CLAIM 9/3/2024 CA101305328 CA101305328 CAMC244750 CAMC244736 CMF 15 ACTIVE LODE CLAIM 9/3/2024 CA101305329 CA101305329 CAMC5967 CAMC5840 SYENITE 131 ACTIVE LODE CLAIM 9/3/2024 CA101305361 CA101305361 CAMC201789 CAMC201787 SYENITE 91 ACTIVE LODE CLAIM 9/3/2024 CA101305378 CA101305378 CAMC234486 CAMC234416 SYENITE 264 ACTIVE LODE CLAIM 9/3/2024 CA101330471 CA101330471 CAMC301781 CAMC301781 EAST SYENITE 3 FILED LODE CLAIM 9/3/2024 CA101330472 CA101330472 CAMC301782 CAMC301781 EAST SYENITE 4 FILED LODE CLAIM 9/3/2024 CA101330473 CA101330473 CAMC301783 CAMC301781 EAST SYENITE 5 FILED LODE CLAIM 9/3/2024 CA101330474 CA101330474 CAMC301784 CAMC301781 EAST SYENITE 6 FILED LODE CLAIM 9/3/2024 CA101330475 CA101330475 CAMC301785 CAMC301781 EAST SYENITE 7 FILED LODE CLAIM 9/3/2024 CA101330476 CA101330476 CAMC301786 CAMC301781 EAST SYENITE 8 FILED LODE CLAIM 9/3/2024 CA101330477 CA101330477 CAMC301787 CAMC301781 EAST SYENITE 9 FILED LODE CLAIM 9/3/2024 CA101330478 CA101330478 CAMC301788 CAMC301781 EAST SYENITE 10 FILED LODE CLAIM 9/3/2024 CA101330479 CA101330479 CAMC301789 CAMC301781 EAST SYENITE 11 FILED LODE CLAIM 9/3/2024 CA101330480 CA101330480 CAMC301790 CAMC301781 EAST SYENITE 12 FILED LODE CLAIM 9/3/2024 CA101330481 CA101330481 CAMC301791 CAMC301781 EAST SYENITE 13 FILED LODE CLAIM 9/3/2024 CA101330482 CA101330482 CAMC301792 CAMC301781 EAST SYENITE 14 FILED LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

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SRKConsulting (U.S.), Inc. SEC Technical Report Summary - Mountain Pass Mine Date and Time Run: 10/4/2023 7:29:38 PM Page 3 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101330483 CA101330483 CAMC301793 CAMC301781 EAST SYENITE 15 FILED LODE CLAIM 9/3/2024 CA101330484 CA101330484 CAMC301794 CAMC301781 EAST SYENITE 16 FILED LODE CLAIM 9/3/2024 CA101330485 CA101330485 CAMC301795 CAMC301781 EAST SYENITE 17 FILED LODE CLAIM 9/3/2024 CA101330486 CA101330486 CAMC301796 CAMC301781 EAST SYENITE 18 FILED LODE CLAIM 9/3/2024 CA101331143 CA101331143 CAMC244781 CAMC244736 CMF 46 ACTIVE LODE CLAIM 9/3/2024 CA101331170 CA101331170 CAMC5981 CAMC5840 SYENITE 145 ACTIVE LODE CLAIM 9/3/2024 CA101331171 CA101331171 CAMC17406 CAMC17399 SYENITE 172 ACTIVE LODE CLAIM 9/3/2024 CA101331221 CA101331221 CAMC5989 CAMC5840 SYENITE 154 ACTIVE LODE CLAIM 9/3/2024 CA101331243 CA101331243 CAMC233776 CAMC233774 SYENITE 168A ACTIVE LODE CLAIM 9/3/2024 CA101331274 CA101331274 CAMC301797 CAMC301781 EAST SYENITE 19 FILED LODE CLAIM 9/3/2024 CA101331275 CA101331275 CAMC301798 CAMC301781 EAST SYENITE 20 FILED LODE CLAIM 9/3/2024 CA101331276 CA101331276 CAMC301799 CAMC301781 EAST SYENITE 21 FILED LODE CLAIM 9/3/2024 CA101331277 CA101331277 CAMC301800 CAMC301781 EAST SYENITE 22 FILED LODE CLAIM 9/3/2024 CA101331278 CA101331278 CAMC301801 CAMC301781 EAST SYENITE 23 FILED LODE CLAIM 9/3/2024 CA101331279 CA101331279 CAMC301802 CAMC301781 EAST SYENITE 24 FILED LODE CLAIM 9/3/2024 CA101331280 CA101331280 CAMC301803 CAMC301781 EAST SYENITE 25 FILED LODE CLAIM 9/3/2024 CA101331281 CA101331281 CAMC301804 CAMC301781 EAST SYENITE 26 FILED LODE CLAIM 9/3/2024 CA101331282 CA101331282 CAMC301805 CAMC301781 EAST SYENITE 27 FILED LODE CLAIM 9/3/2024 CA101331283 CA101331283 CAMC301806 CAMC301781 EAST SYENITE 28 FILED LODE CLAIM 9/3/2024 CA101331284 CA101331284 CAMC301807 CAMC301781 EAST SYENITE 29 FILED LODE CLAIM 9/3/2024 CA101331285 CA101331285 CAMC301808 CAMC301781 EAST SYENITE 30 FILED LODE CLAIM 9/3/2024 CA101331286 CA101331286 CAMC301809 CAMC301781 EAST SYENITE 31 FILED LODE CLAIM 9/3/2024 CA101331287 CA101331287 CAMC301810 CAMC301781 EAST SYENITE 32 FILED LODE CLAIM 9/3/2024 CA101331288 CA101331288 CAMC301811 CAMC301781 EAST SYENITE 33 FILED LODE CLAIM 9/3/2024 CA101331289 CA101331289 CAMC301812 CAMC301781 EAST SYENITE 34 FILED LODE CLAIM 9/3/2024 CA101331290 CA101331290 CAMC301813 CAMC301781 EAST SYENITE 35 FILED LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

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Date and Time Run: 10/4/2023 7:29:38 PM Page 4 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101331291 CA101331291 CAMC301814 CAMC301781 EAST SYENITE 36 FILED LODE CLAIM 9/3/2024 CA101331292 CA101331292 CAMC301815 CAMC301781 EAST SYENITE 37 FILED LODE CLAIM 9/3/2024 CA101331293 CA101331293 CAMC301816 CAMC301781 EAST SYENITE 38 FILED LODE CLAIM 9/3/2024 CA101331294 CA101331294 CAMC301817 CAMC301781 EAST SYENITE 39 FILED LODE CLAIM 9/3/2024 CA101331951 CA101331951 CAMC5861 CAMC5840 SYENITE 22 ACTIVE LODE CLAIM 9/3/2024 CA101331971 CA101331971 CAMC5931 CAMC5840 SYENITE 93 ACTIVE LODE CLAIM 9/3/2024 CA101332007 CA101332007 CAMC47663 CAMC47621 BAILEY 50 ACTIVE LODE CLAIM 9/3/2024 CA101332024 CA101332024 CAMC5939 CAMC5840 SYENITE 103 ACTIVE LODE CLAIM 9/3/2024 CA101332041 CA101332041 CAMC47637 CAMC47621 BAILEY 17 ACTIVE LODE CLAIM 9/3/2024 CA101332086 CA101332086 CAMC301818 CAMC301781 EAST SYENITE 40 FILED LODE CLAIM 9/3/2024 CA101332768 CA101332768 CAMC244124 CAMC244124 SYENITE 297 ACTIVE LODE CLAIM 9/3/2024 CA101332798 CA101332798 CAMC177641 CAMC177640 SOUTH SYENITE 2 ACTIVE LODE CLAIM 9/3/2024 CA101332810 CA101332810 CAMC233778 CAMC233774 SYENITE 173A ACTIVE LODE CLAIM 9/3/2024 CA101332820 CA101332820 CAMC244801 CAMC244736 CMF 66 ACTIVE LODE CLAIM 9/3/2024 CA101332821 CA101332821 CAMC234466 CAMC234416 SYENITE 244 ACTIVE LODE CLAIM 9/3/2024 CA101332828 CA101332828 CAMC5884 CAMC5840 SYENITE 45 ACTIVE LODE CLAIM 9/3/2024 CA101333498 CA101333498 CAMC245120 CAMC245118 SOUTH SYENITE 109 ACTIVE LODE CLAIM 9/3/2024 CA101333517 CA101333517 CAMC5999 CAMC5840 SYENITE 164 ACTIVE LODE CLAIM 9/3/2024 CA101333526 CA101333526 CAMC5876 CAMC5840 SYENITE 37 ACTIVE LODE CLAIM 9/3/2024 CA101333529 CA101333529 CAMC5949 CAMC5840 SYENITE 113 ACTIVE LODE CLAIM 9/3/2024 CA101333542 CA101333542 CAMC234429 CAMC234416 SYENITE 207 ACTIVE LODE CLAIM 9/3/2024 CA101333548 CA101333548 CAMC5851 CAMC5840 SYENITE 12 ACTIVE LODE CLAIM 9/3/2024 CA101333564 CA101333564 CAMC5995 CAMC5840 SYENITE 160 ACTIVE LODE CLAIM 9/3/2024 CA101333572 CA101333572 CAMC5945 CAMC5840 SYENITE 109 ACTIVE LODE CLAIM 9/3/2024 CA101333573 CA101333573 CAMC47669 CAMC47621 BAILEY 56 ACTIVE LODE CLAIM 9/3/2024 CA101333588 CA101333588 CAMC234487 CAMC234416 SYENITE 265 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

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SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 5 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101333600 CA101333600 CAMC234424 CAMC234416 SYENITE 202 ACTIVE LODE CLAIM 9/3/2024 CA101334335 CA101334335 CAMC177680 CAMC177640 SOUTH SYENITE 41 ACTIVE LODE CLAIM 9/3/2024 CA101334336 CA101334336 CAMC234468 CAMC234416 SYENITE 246 ACTIVE LODE CLAIM 9/3/2024 CA101335033 CA101335033 CAMC122227 CAMC122227 DESERT POPPY 2 ACTIVE LODE CLAIM 9/3/2024 CA101335038 CA101335038 CAMC51748 CAMC51692 LUCKY STRIKE NO 4 ACTIVE LODE CLAIM 9/3/2024 CA101335040 CA101335040 CAMC5955 CAMC5840 SYENITE 119 ACTIVE LODE CLAIM 9/3/2024 CA101335046 CA101335046 CAMC5926 CAMC5840 SYENITE 87 ACTIVE LODE CLAIM 9/3/2024 CA101335057 CA101335057 CAMC177737 CAMC177640 SOUTH SYENITE 98 ACTIVE LODE CLAIM 9/3/2024 CA101335073 CA101335073 CAMC47665 CAMC47621 BAILEY 52 ACTIVE LODE CLAIM 9/3/2024 CA101335077 CA101335077 CAMC5869 CAMC5840 SYENITE 30 ACTIVE LODE CLAIM 9/3/2024 CA101335099 CA101335099 CAMC234489 CAMC234416 SYENITE 267 ACTIVE LODE CLAIM 9/3/2024 CA101335742 CA101335742 CAMC245121 CAMC245118 SOUTH SYENITE 110 ACTIVE LODE CLAIM 9/3/2024 CA101335773 CA101335773 CAMC5905 CAMC5840 SYENITE 66 ACTIVE LODE CLAIM 9/3/2024 CA101335799 CA101335799 CAMC5880 CAMC5840 SYENITE 41 ACTIVE LODE CLAIM 9/3/2024 CA101335810 CA101335810 CAMC244803 CAMC244736 CMF 68 ACTIVE LODE CLAIM 9/3/2024 CA101335834 CA101335834 CAMC234426 CAMC234416 SYENITE 204 ACTIVE LODE CLAIM 9/3/2024 CA101336526 CA101336526 CAMC47661 CAMC47621 BAILEY 41 ACTIVE LODE CLAIM 9/3/2024 CA101336540 CA101336540 CAMC47633 CAMC47621 BAILEY 13 ACTIVE LODE CLAIM 9/3/2024 CA101336564 CA101336564 CAMC234447 CAMC234416 SYENITE 225 ACTIVE LODE CLAIM 9/3/2024 CA101337163 CA101337163 CAMC5974 CAMC5840 SYENITE 138 ACTIVE LODE CLAIM 9/3/2024 CA101337190 CA101337190 CAMC17408 CAMC17399 SYENITE 174 ACTIVE LODE CLAIM 9/3/2024 CA101337191 CA101337191 CAMC16272 CAMC16264 MINERAL HILL NO 9 ACTIVE LODE CLAIM 9/3/2024 CA101337212 CA101337212 CAMC5894 CAMC5840 SYENITE 55 ACTIVE LODE CLAIM 9/3/2024 CA101337812 CA101337812 CAMC16270 CAMC16264 MINERAL HILL NO 7 ACTIVE LODE CLAIM 9/3/2024 CA101337825 CA101337825 CAMC5873 CAMC5840 SYENITE 34 ACTIVE LODE CLAIM 9/3/2024 CA101337837 CA101337837 CAMC6002 CAMC5840 SYENITE 167 FILED LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 6 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101337862 CA101337862 CAMC177640 CAMC177640 SOUTH SYENITE 1 ACTIVE LODE CLAIM 9/3/2024 CA101337863 CA101337863 CAMC234428 CAMC234416 SYENITE 206 ACTIVE LODE CLAIM 9/3/2024 CA101338439 CA101338439 CAMC51744 CAMC51692 EARL NO 6 ACTIVE LODE CLAIM 9/3/2024 CA101338442 CA101338442 CAMC101870 CAMC101865 SYENITE #182 ACTIVE LODE CLAIM 9/3/2024 CA101338452 CA101338452 CAMC244780 CAMC244736 CMF 45 ACTIVE LODE CLAIM 9/3/2024 CA101338462 CA101338462 CAMC51694 CAMC51692 CLARK MOUNTAIN NO 12 ACTIVE LODE CLAIM 9/3/2024 CA101338481 CA101338481 CAMC5844 CAMC5840 SYENITE 5 ACTIVE LODE CLAIM 9/3/2024 CA101338510 CA101338510 CAMC234449 CAMC234416 SYENITE 227 ACTIVE LODE CLAIM 9/3/2024 CA101338523 CA101338523 CAMC5992 CAMC5840 SYENITE 157 ACTIVE LODE CLAIM 9/3/2024 CA101338528 CA101338528 CAMC233777 CAMC233774 SYENITE 169A ACTIVE LODE CLAIM 9/3/2024 CA101338533 CA101338533 CAMC5942 CAMC5840 SYENITE 106 ACTIVE LODE CLAIM 9/3/2024 CA101338534 CA101338534 CAMC47639 CAMC47621 BAILEY 19 ACTIVE LODE CLAIM 9/3/2024 CA101338538 CA101338538 CAMC244800 CAMC244736 CMF 65 ACTIVE LODE CLAIM 9/3/2024 CA101339113 CA101339113 CAMC244125 CAMC244124 SYENITE 296 ACTIVE LODE CLAIM 9/3/2024 CA101339139 CA101339139 CAMC5952 CAMC5840 SYENITE 116 ACTIVE LODE CLAIM 9/3/2024 CA101339148 CA101339148 CAMC51698 CAMC51692 CLARK MOUNTAIN NO 16 ACTIVE LODE CLAIM 9/3/2024 CA101339173 CA101339173 CAMC47635 CAMC47621 BAILEY 15 ACTIVE LODE CLAIM 9/3/2024 CA101347058 CA101347058 CAMC51700 CAMC51692 CLARK MOUNTAIN NO 18 ACTIVE LODE CLAIM 9/3/2024 CA101347320 CA101347320 CAMC5980 CAMC5840 SYENITE 144 ACTIVE LODE CLAIM 9/3/2024 CA101347324 CA101347324 CAMC234475 CAMC234416 SYENITE 253 ACTIVE LODE CLAIM 9/3/2024 CA101347329 CA101347329 CAMC5930 CAMC5840 SYENITE 92 ACTIVE LODE CLAIM 9/3/2024 CA101347354 CA101347354 CAMC5875 CAMC5840 SYENITE 36 ACTIVE LODE CLAIM 9/3/2024 CA101347356 CA101347356 CAMC5944 CAMC5840 SYENITE 108 ACTIVE LODE CLAIM 9/3/2024 CA101347357 CA101347357 CAMC244791 CAMC244736 CMF 56 ACTIVE LODE CLAIM 9/3/2024 CA101347592 CA101347592 CAMC234474 CAMC234416 SYENITE 252 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 7 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101347643 CA101347643 CAMC234434 CAMC234416 SYENITE 212 ACTIVE LODE CLAIM 9/3/2024 CA101347680 CA101347680 CAMC234455 CAMC234416 SYENITE 233 ACTIVE LODE CLAIM 9/3/2024 CA101347895 CA101347895 CAMC5891 CAMC5840 SYENITE 52 ACTIVE LODE CLAIM 9/3/2024 CA101347898 CA101347898 CAMC234423 CAMC234416 SYENITE 201 ACTIVE LODE CLAIM 9/3/2024 CA101347915 CA101347915 CAMC5841 CAMC5840 SYENITE 2 ACTIVE LODE CLAIM 9/3/2024 CA101347924 CA101347924 CAMC234444 CAMC234416 SYENITE 222 ACTIVE LODE CLAIM 9/3/2024 CA101347958 CA101347958 CAMC234433 CAMC234416 SYENITE 211 ACTIVE LODE CLAIM 9/3/2024 CA101348272 CA101348272 CAMC5997 CAMC5840 SYENITE 162 ACTIVE LODE CLAIM 9/3/2024 CA101348380 CA101348380 CAMC5921 CAMC5840 SYENITE 82 ACTIVE LODE CLAIM 9/3/2024 CA101348430 CA101348430 CAMC233785 CAMC233774 SYENITE 193 ACTIVE LODE CLAIM 9/3/2024 CA101348441 CA101348441 CAMC234465 CAMC234416 SYENITE 243 ACTIVE LODE CLAIM 9/3/2024 CA101348457 CA101348457 CAMC215721 CAMC215721 SYENITE 186 ACTIVE LODE CLAIM 9/3/2024 CA101348599 CA101348599 CAMC234464 CAMC234416 SYENITE 242 ACTIVE LODE CLAIM 9/3/2024 CA101348600 CA101348600 CAMC5865 CAMC5840 SYENITE 26 ACTIVE LODE CLAIM 9/3/2024 CA101349355 CA101349355 CAMC244739 CAMC244736 CMF 4 ACTIVE LODE CLAIM 9/3/2024 CA101349452 CA101349452 CAMC244792 CAMC244736 CMF 57 ACTIVE LODE CLAIM 9/3/2024 CA101349456 CA101349456 CAMC5888 CAMC5840 SYENITE 49 ACTIVE LODE CLAIM 9/3/2024 CA101349727 CA101349727 CAMC5859 CAMC5840 SYENITE 20 ACTIVE LODE CLAIM 9/3/2024 CA101349738 CA101349738 CAMC233774 CAMC233774 SYENITE 81A ACTIVE LODE CLAIM 9/3/2024 CA101349791 CA101349791 CAMC234485 CAMC234416 SYENITE 263 ACTIVE LODE CLAIM 9/3/2024 CA101350032 CA101350032 CAMC5963 CAMC5840 SYENITE 127 ACTIVE LODE CLAIM 9/3/2024 CA101350033 CA101350033 CAMC234445 CAMC234416 SYENITE 223 ACTIVE LODE CLAIM 9/3/2024 CA101350037 CA101350037 CAMC5913 CAMC5840 SYENITE 74 ACTIVE LODE CLAIM 9/3/2024 CA101350176 CA101350176 CAMC5918 CAMC5840 SYENITE 79 ACTIVE LODE CLAIM 9/3/2024 CA101350332 CA101350332 CAMC5845 CAMC5840 SYENITE 6 ACTIVE LODE CLAIM 9/3/2024 CA101350334 CA101350334 CAMC5914 CAMC5840 SYENITE 75 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 8 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101350346 CA101350346 CAMC233784 CAMC233774 SYENITE 192 ACTIVE LODE CLAIM 9/3/2024 CA101350372 CA101350372 CAMC51745 CAMC51692 LUCKY STRIKE NO 1 ACTIVE LODE CLAIM 9/3/2024 CA101361815 CA101361815 CAMC244749 CAMC244736 CMF 14 ACTIVE LODE CLAIM 9/3/2024 CA101363414 CA101363414 CAMC51747 CAMC51692 LUCKY STRIKE NO 3 ACTIVE LODE CLAIM 9/3/2024 CA101376605 CA101376605 CAMC234467 CAMC234416 SYENITE 245 ACTIVE LODE CLAIM 9/3/2024 CA101377544 CA101377544 CAMC244782 CAMC244736 CMF 47 ACTIVE LODE CLAIM 9/3/2024 CA101377594 CA101377594 CAMC5998 CAMC5840 SYENITE 163 ACTIVE LODE CLAIM 9/3/2024 CA101377597 CA101377597 CAMC5902 CAMC5840 SYENITE 63 ACTIVE LODE CLAIM 9/3/2024 CA101377635 CA101377635 CAMC5923 CAMC5840 SYENITE 84 ACTIVE LODE CLAIM 9/3/2024 CA101377645 CA101377645 CAMC5988 CAMC5840 SYENITE 153 ACTIVE LODE CLAIM 9/3/2024 CA101377652 CA101377652 CAMC5938 CAMC5840 SYENITE 102 ACTIVE LODE CLAIM 9/3/2024 CA101377660 CA101377660 CAMC177660 CAMC177640 SOUTH SYENITE 21 ACTIVE LODE CLAIM 9/3/2024 CA101377673 CA101377673 CAMC51718 CAMC51692 BEARGRASS ACTIVE LODE CLAIM 9/3/2024 CA101377675 CA101377675 CAMC5887 CAMC5840 SYENITE 48 ACTIVE LODE CLAIM 9/3/2024 CA101377679 CA101377679 CAMC234488 CAMC234416 SYENITE 266 ACTIVE LODE CLAIM 9/3/2024 CA101378502 CA101378502 CAMC51742 CAMC51692 EARL NO 4 ACTIVE LODE CLAIM 9/3/2024 CA101378504 CA101378504 CAMC5977 CAMC5840 SYENITE 141 ACTIVE LODE CLAIM 9/3/2024 CA101378513 CA101378513 CAMC5948 CAMC5840 SYENITE 112 ACTIVE LODE CLAIM 9/3/2024 CA101378559 CA101378559 CAMC244802 CAMC244736 CMF 67 ACTIVE LODE CLAIM 9/3/2024 CA101378567 CA101378567 CAMC233779 CAMC233774 SYENITE 175A ACTIVE LODE CLAIM 9/3/2024 CA101378572 CA101378572 CAMC47667 CAMC47621 BAILEY 54 ACTIVE LODE CLAIM 9/3/2024 CA101378579 CA101378579 CAMC234469 CAMC234416 SYENITE 247 ACTIVE LODE CLAIM 9/3/2024 CA101378597 CA101378597 CAMC234425 CAMC234416 SYENITE 203 ACTIVE LODE CLAIM 9/3/2024 CA101378615 CA101378615 CAMC234446 CAMC234416 SYENITE 224 ACTIVE LODE CLAIM 9/3/2024 CA101379414 CA101379414 CAMC51746 CAMC51692 LUCKY STRIKE NO 2 ACTIVE LODE CLAIM 9/3/2024 CA101379430 CA101379430 CAMC122228 CAMC122227 BRENDA ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 9 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101379437 CA101379437 CAMC51696 CAMC51692 CLARK MOUNTAIN NO 14 ACTIVE LODE CLAIM 9/3/2024 CA101379440 CA101379440 CAMC5897 CAMC5840 SYENITE 58 ACTIVE LODE CLAIM 9/3/2024 CA101379470 CA101379470 CAMC5971 CAMC5840 SYENITE 135 ACTIVE LODE CLAIM 9/3/2024 CA101379484 CA101379484 CAMC234427 CAMC234416 SYENITE 205 ACTIVE LODE CLAIM 9/3/2024 CA101379500 CA101379500 CAMC5966 CAMC5840 SYENITE 130 ACTIVE LODE CLAIM 9/3/2024 CA101379507 CA101379507 CAMC5916 CAMC5840 SYENITE 77 ACTIVE LODE CLAIM 9/3/2024 CA101380331 CA101380331 CAMC244804 CAMC244736 CMF 69 ACTIVE LODE CLAIM 9/3/2024 CA101380340 CA101380340 CAMC5868 CAMC5840 SYENITE 29 ACTIVE LODE CLAIM 9/3/2024 CA101380345 CA101380345 CAMC47631 CAMC47621 BAILEY 11 ACTIVE LODE CLAIM 9/3/2024 CA101380377 CA101380377 CAMC234448 CAMC234416 SYENITE 226 ACTIVE LODE CLAIM 9/3/2024 CA101380394 CA101380394 CAMC5870 CAMC5840 SYENITE 31 ACTIVE LODE CLAIM 9/3/2024 CA101451263 CA101451263 CAMC5962 CAMC5840 SYENITE 126 ACTIVE LODE CLAIM 9/3/2024 CA101451444 CA101451444 CAMC16267 CAMC16264 MINERAL HILL NO 4 ACTIVE LODE CLAIM 9/3/2024 CA101451505 CA101451505 CAMC47630 CAMC47621 BAILEY 10 ACTIVE LODE CLAIM 9/3/2024 CA101451561 CA101451561 CAMC244747 CAMC244736 CMF 12 ACTIVE LODE CLAIM 9/3/2024 CA101451562 CA101451562 CAMC233781 CAMC233774 SYENITE 183A ACTIVE LODE CLAIM 9/3/2024 CA101451565 CA101451565 CAMC47653 CAMC47621 BAILEY 33 ACTIVE LODE CLAIM 9/3/2024 CA101451818 CA101451818 CAMC5986 CAMC5840 SYENITE 151 ACTIVE LODE CLAIM 9/3/2024 CA101451875 CA101451875 CAMC177688 CAMC177640 SOUTH SYENITE 49 ACTIVE LODE CLAIM 9/3/2024 CA101451919 CA101451919 CAMC16268 CAMC16264 MINERAL HILL NO 5 ACTIVE LODE CLAIM 9/3/2024 CA101451930 CA101451930 CAMC177656 CAMC1 77640 SOUTH SYENITE 17 ACTIVE LODE CLAIM 9/3/2024 CA101452024 CA101452024 CAMC5936 CAMC5840 SYENITE 100 ACTIVE LODE CLAIM 9/3/2024 CA101452113 CA101452113 CAMC234471 CAMC234416 SYENITE 249 ACTIVE LODE CLAIM 9/3/2024 CA101452187 CA101452187 CAMC234492 CAMC234416 SYENITE 270 ACTIVE LODE CLAIM 9/3/2024 CA101452286 CA101452286 CAMC247590 CAMC247586 CMF 74 ACTIVE LODE CLAIM 9/3/2024 CA101452294 CA101452294 CAMC5956 CAMC5840 SYENITE 120 ACTIVE LODE 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 10 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CLAIM CA101452296 CA101452296 CAMC101868 CAMC101865 SYENITE #180 ACTIVE LODE CLAIM 9/3/2024 CA101452298 CA101452298 CAMC234440 CAMC234416 SYENITE 218 ACTIVE LODE CLAIM 9/3/2024 CA101452383 CA101452383 CAMC5906 CAMC5840 SYENITE 67 ACTIVE LODE CLAIM 9/3/2024 CA101452386 CA101452386 CAMC177646 CAMC177640 SOUTH SYENITE 7 ACTIVE LODE CLAIM 9/3/2024 CA101452482 CA101452482 CAMC5850 CAMC5840 SYENITE 11 ACTIVE LODE CLAIM 9/3/2024 CA101452487 CA101452487 CAMC177677 CAMC177640 SOUTH SYENITE 38 ACTIVE LODE CLAIM 9/3/2024 CA101452551 CA101452551 CAMC234419 CAMC234416 SYENITE 197 ACTIVE LODE CLAIM 9/3/2024 CA101452666 CA101452666 CAMC244778 CAMC244736 CMF 43 ACTIVE LODE CLAIM 9/3/2024 CA101452669 CA101452669 CAMC120581 CAMC120576 DESERT POPPY 5 ACTIVE LODE CLAIM 9/3/2024 CA101452805 CA101452805 CAMC5853 CAMC5840 SYENITE 14 ACTIVE LODE CLAIM 9/3/2024 CA101452888 CA101452888 CAMC47670 CAMC47621 BAILEY 57 ACTIVE LODE CLAIM 9/3/2024 CA101453075 CA101453075 CAMC177690 CAMC177640 SOUTH SYENITE 51 ACTIVE LODE CLAIM 9/3/2024 CA101453197 CA101453197 CAMC47622 CAMC47621 BAILEY 2 ACTIVE LODE CLAIM 9/3/2024 CA101453367 CA101453367 CAMC201790 CAMC201787 SYENITE 94 ACTIVE LODE CLAIM 9/3/2024 CA101453393 CA101453393 CAMC47655 CAMC47621 BAILEY 35 ACTIVE LODE CLAIM 9/3/2024 CA101453396 CA101453396 CAMC234450 CAMC234416 SYENITE 228 ACTIVE LODE CLAIM 9/3/2024 CA101453397 CA101453397 CAMC5864 CAMC5840 SYENITE 25 ACTIVE LODE CLAIM 9/3/2024 CA101453491 CA101453491 CAMC47646 CAMC47621 BAILEY 26 ACTIVE LODE CLAIM 9/3/2024 CA101453494 CA101453494 CAMC177651 CAMC177640 SOUTH SYENITE 12 ACTIVE LODE CLAIM 9/3/2024 CA101453588 CA101453588 CAMC177672 CAMC177640 SOUTH SYENITE 33 ACTIVE LODE CLAIM 9/3/2024 CA101453770 CA101453770 CAMC234478 CAMC234416 SYENITE 256 ACTIVE LODE CLAIM 9/3/2024 CA101453886 CA101453886 CAMC177667 CAMC177640 SOUTH SYENITE 28 ACTIVE LODE CLAIM 9/3/2024 CA101454110 CA101454110 CAMC234461 CAMC234416 SYENITE 239 ACTIVE LODE CLAIM 9/3/2024 CA101454113 CA101454113 CAMC5877 CAMC5840 SYENITE 38 ACTIVE LODE CLAIM 9/3/2024 CA101454190 CA101454190 CAMC234482 CAMC234416 SYENITE 260 ACTIVE LODE CLAIM 9/3/2024 CA101454389 CA101454389 CAMC234481 CAMC234416 SYENITE 259 ACTIVE LODE 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 11 of 21 DEPARTIRENT O F THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CLAIM CA101454544 CA101454544 CAMC5857 CAMC5840 SYENITE 18 ACTIVE LODE CLAIM 9/3/2024 CA101454626 CA101454626 CAMC244788 CAMC244736 CMF 53 ACTIVE LODE CLAIM 9/3/2024 CA101454670 CA101454670 CAMC244783 CAMC244736 CMF 48 ACTIVE LODE CLAIM 9/3/2024 CA101454798 CA101454798 CAMC234418 CAMC234416 SYENITE 196 ACTIVE LODE CLAIM 9/3/2024 CA101454900 CA101454900 CAMC177655 CAMC177640 SOUTH SYENITE 16 ACTIVE LODE CLAIM 9/3/2024 CA101454909 CA101454909 CAMC47662 CAMC47621 BAILEY 42 ACTIVE LODE CLAIM 9/3/2024 CA101455024 CA101455024 CAMC234460 CAMC234416 SYENITE 238 ACTIVE LODE CLAIM 9/3/2024 CA101455025 CA101455025 CAMC16269 CAMC16264 MINERAL HILL NO 6 ACTIVE LODE CLAIM 9/3/2024 CA101455032 CA101455032 CAMC177666 CAMC177640 SOUTH SYENITE 27 ACTIVE LODE CLAIM 9/3/2024 CA101455092 CAIO1455092 CAMC177687 CAMC177640 SOUTH SYENITE 48 ACTIVE LODE CLAIM 9/3/2024 CA101455309 CA101455309 CAMC120577 CAMC120576 DESERT POPPY 1 ACTIVE LODE CLAIM 9/3/2024 CA101455314 CA101455314 CAMC234457 CAMC234416 SYENITE 235 ACTIVE LODE CLAIM 9/3/2024 CA101455398 CA101455398 CAMC245122 CAMC245118 SOUTH SYENITE 111 ACTIVE LODE CLAIM 9/3/2024 CA101455399 CA101455399 CAMC244741 CAMC244736 CMF 6 ACTIVE LODE CLAIM 9/3/2024 CA101455462 CA101455462 CAMC247586 CAMC247586 CMF 70 ACTIVE LODE CLAIM 9/3/2024 CA101455615 CA101455615 CAMC5933 CAMC5840 SYENITE 97 ACTIVE LODE CLAIM 9/3/2024 CA101455694 CA101455694 CAMC51702 CAMC51692 CLARK MOUNTAIN NO 20 ACTIVE LODE CLAIM 9/3/2024 CA101455700 CA101455700 CAMC234470 CAMC234416 SYENITE 248 ACTIVE LODE CLAIM 9/3/2024 CA101456043 CA101456043 CAMC47654 CAMC47621 BAILEY 34 ACTIVE LODE CLAIM 9/3/2024 CA101456046 CA101456046 CAMC5874 CAMC5840 SYENITE 35 ACTIVE LODE CLAIM 9/3/2024 CA101456249 CA101456249 CAMC17400 CAMC17399 SYENITE 191 ACTIVE LODE CLAIM 9/3/2024 CA101456456 CA101456456 CAMC234436 CAMC234416 SYENITE 214 ACTIVE LODE CLAIM 9/3/2024 CA101456846 CA101456846 CAMC177676 CAMC177640 SOUTH SYENITE 37 ACTIVE LODE CLAIM 9/3/2024 CA101456915 CA101456915 CAMC101867 CAMC101865 SYENITE #179 ACTIVE LODE CLAIM 9/3/2024 CA101456921 CA101456921 CAMC177645 CAMC177640 SOUTH SYENITE 6 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 12 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101457204 CA101457204 CAMC5912 CAMC5840 SYENITE 73 ACTIVE LODE CLAIM 9/3/2024 CA101457207 CA101457207 CAMC51740 CAMC51692 EARL NO 2 ACTIVE LODE CLAIM 9/3/2024 CA101457536 CA101457536 CAMC245127 CAMC245118 SOUTH SYENITE 116 ACTIVE LODE CLAIM 9/3/2024 CA101457538 CA101457538 CAMC233780 CAMC233774 SYENITE 176A ACTIVE LODE CLAIM 9/3/2024 CA101457664 CA101457664 CAMC244794 CAMC244736 CMF 59 ACTIVE LODE CLAIM 9/3/2024 CA101457670 CA101457670 CAMC5972 CAMC5840 SYENITE 136 ACTIVE LODE CLAIM 9/3/2024 CA101457705 CA101457705 CAMC47640 CAMC47621 BAILEY 20 ACTIVE LODE CLAIM 9/3/2024 CA101457706 CA101457706 CAMC234491 CAMC234416 SYENITE 269 ACTIVE LODE CLAIM 9/3/2024 CA101457805 CA101457805 CAMC244762 CAMC244736 CMF 27 ACTIVE LODE CLAIM 9/3/2024 CA101457860 CA101457860 CAMC5878 CAMC5840 SYENITE 39 ACTIVE LODE CLAIM 9/3/2024 CA101457865 CA101457865 CAMC177700 CAMC177640 SOUTH SYENITE 61 ACTIVE LODE CLAIM 9/3/2024 CA101457866 CA101457866 CAMC244777 CAMC244736 CMF 42 ACTIVE LODE CLAIM 9/3/2024 CA101457869 CA101457869 CAMC120580 CAMC120576 DESERT POPPY 4 ACTIVE LODE CLAIM 9/3/2024 CA101457872 CA101457872 CAMC47656 CAMC47621 BAILEY 36 ACTIVE LODE CLAIM 9/3/2024 CA101457920 CA101457920 CAMC47625 CAMC47621 BAILEY 5 ACTIVE LODE CLAIM 9/3/2024 CA101458121 CA101458121 CAMC5983 CAMC5840 SYENITE 147 ACTIVE LODE CLAIM 9/3/2024 CA101458461 CA101458461 CAMC5953 CAMC5840 SYENITE 117 ACTIVE LODE CLAIM 9/3/2024 CA101458647 CA101458647 CAMC47623 CAMC47621 BAILEY 3 ACTIVE LODE CLAIM 9/3/2024 CA101458882 CA101458882 CAMC244752 CAMC244736 CMF 17 ACTIVE LODE CLAIM 9/3/2024 CA101458961 CA101458961 CAMC5903 CAMC5840 SYENITE 64 ACTIVE LODE CLAIM 9/3/2024 CA101459245 CA101459245 CAMC120583 CAMC120576 DESERT POPPY 7 ACTIVE LODE CLAIM 9/3/2024 CA101459247 CA101459247 CAMC234442 CAMC234416 SYENITE 220 ACTIVE LODE CLAIM 9/3/2024 CA101459250 CA101459250 CAMC5979 CAMC5840 SYENITE 143 ACTIVE LODE CLAIM 9/3/2024 CA101459515 CA101459515 CAMC47652 CAMC47621 BAILEY 32 ACTIVE LODE CLAIM 9/3/2024 CA101459952 CA101459952 CAMC47660 CAMC47621 BAILEY 40 ACTIVE LODE CLAIM 9/3/2024 CA101459977 CA101459977 CAMC177657 CAMC177640 SOUTH SYENITE 18 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 13 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101459983 CA101459983 CAMC234472 CAMC234416 SYENITE 250 ACTIVE LODE CLAIM 9/3/2024 CA101460015 CA101460015 CAMC101869 CAMC101865 SYENITE #181 ACTIVE LODE CLAIM 9/3/2024 CA101460035 CA101460035 CAMC234430 CAMC234416 SYENITE 208 ACTIVE LODE CLAIM 9/3/2024 CA101460133 CA101460133 CAMC5976 CAMC5840 SYENITE 140 ACTIVE LODE CLAIM 9/3/2024 CA101460369 CA101460369 CAMC51719 CAMC51692 BIRTHDAY NO 1 ACTIVE LODE CLAIM 9/3/2024 CA101477207 CA101477207 CAMC5907 CAMC5840 SYENITE 68 ACTIVE LODE CLAIM 9/3/2024 CA101477346 CA101477346 CAMC5990 CAMC5840 SYENITE 155 ACTIVE LODE CLAIM 9/3/2024 CA101477352 CA101477352 CAMC47664 CAMC47621 BAILEY 51 ACTIVE LODE CLAIM 9/3/2024 CA101477429 CA101477429 CAMC234438 CAMC234416 SYENITE 216 ACTIVE LODE CLAIM 9/3/2024 CA101477431 CA101477431 CAMC5882 CAMC5840 SYENITE 43 ACTIVE LODE CLAIM 9/3/2024 CA101477536 CA101477536 CAMC177675 CAMC177640 SOUTH SYENITE 36 ACTIVE LODE CLAIM 9/3/2024 CA101477544 CA101477544 CAMC5940 CAMC5840 SYENITE 104 ACTIVE LODE CLAIM 9/3/2024 CA101477546 CA101477546 CAMC5879 CAMC5840 SYENITE 40 ACTIVE LODE CLAIM 9/3/2024 CA101477592 CA101477592 CAMC51704 CAMC51692 CLARK MOUNTAIN NO 22 ACTIVE LODE CLAIM 9/3/2024 CA101477595 CA101477595 CAMC234490 CAMC234416 SYENITE 268 ACTIVE LODE CLAIM 9/3/2024 CA101477618 CA101477618 CAMC244796 CAMC244736 CMF 61 ACTIVE LODE CLAIM 9/3/2024 CA101477651 CA101477651 CAMC120579 CAMC120576 DESERT POPPY 3 ACTIVE LODE CLAIM 9/3/2024 CA101477720 CA101477720 CAMC47674 CAMC47621 BAILEY 63 ACTIVE LODE CLAIM 9/3/2024 CA101477723 CA101477723 CAMC5941 CAMC5840 SYENITE 105 ACTIVE LODE CLAIM 9/3/2024 CA101477724 CA101477724 CAMC47629 CAMC47621 BAILEY 9 ACTIVE LODE CLAIM 9/3/2024 CA101477742 CA101477742 CAMC213565 CAMC213564 EAST SYENITE #1 ACTIVE LODE CLAIM 9/3/2024 CA101477745 CA101477745 CAMC47671 CAMC47621 BAILEY 58 ACTIVE LODE CLAIM 9/3/2024 CA101477750 CA101477750 CAMC101866 CAMC101865 SYENITE #178 ACTIVE LODE CLAIM 9/3/2024 CA101477751 CA101477751 CAMC47626 CAMC47621 BAILEY 6 ACTIVE LODE CLAIM 9/3/2024 CA101477783 CA101477783 CAMC244754 CAMC244736 CMF 19 ACTIVE LODE CLAIM 9/3/2024 CA101477991 CA101477991 CAMC51721 CAMC51692 BIRTHDAY ACTIVE LODE 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 14 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date NO 6 CLAIM CA101478201 CA101478201 CAMC47628 CAMC47621 BAILEY 8 ACTIVE LODE CLAIM 9/3/2024 CA101478210 CA101478210 CAMC5928 CAMC5840 SYENITE 89 ACTIVE LODE CLAIM 9/3/2024 CA101478745 CA101478745 CAMC244785 CAMC244736 CMF 50 ACTIVE LODE CLAIM 9/3/2024 CA101478981 CA101478981 CAMC244776 CAMC244736 CMF41 ACTIVE LODE CLAIM 9/3/2024 CA101479076 CA101479076 CAMC5991 CAMC5840 SYENITE 156 ACTIVE LODE CLAIM 9/3/2024 CA101479330 CA101479330 CAMC244764 CAMC244736 CMF 29 ACTIVE LODE CLAIM 9/3/2024 CA101479333 CA101479333 CAMC233828 CAMC233827 SYENITE 190A ACTIVE LODE CLAIM 9/3/2024 CA101479409 CA101479409 CAMC47624 CAMC47621 BAILEY 4 ACTIVE LODE CLAIM 9/3/2024 CA101479601 CA101479601 CAMC5848 CAMC5840 SYENITE 9 ACTIVE LODE CLAIM 9/3/2024 CA101479717 CA101479717 CAMC5852 CAMC5840 SYENITE 13 ACTIVE LODE CLAIM 9/3/2024 CA101479722 CA101479722 CAMC234459 CAMC234416 SYENITE 237 ACTIVE LODE CLAIM 9/3/2024 CA101479724 CA101479724 CAMC177701 CAMC177640 SOUTH SYENITE 62 ACTIVE LODE CLAIM 9/3/2024 CA101480382 CA101480382 CAMC177644 CAMC177640 SOUTH SYENITE 5 ACTIVE LODE CLAIM 9/3/2024 CA101480388 CA101480388 CAMC5960 CAMC5840 SYENITE 124 ACTIVE LODE CLAIM 9/3/2024 CA101490538 CA101490538 CAMC234441 CAMC234416 SYENITE 219 ACTIVE LODE CLAIM 9/3/2024 CA101490641 CA101490641 CAMC244766 CAMC244736 CMF 31 ACTIVE LODE CLAIM 9/3/2024 CA101490698 CA101490698 CAMC5890 CAMC5840 SYENITE 51 ACTIVE LODE CLAIM 9/3/2024 CA101490847 CA101490847 CAMC234421 CAMC234416 SYENITE 199 ACTIVE LODE CLAIM 9/3/2024 CA101490931 CA101490931 CAMC245118 CAMC245118 SOUTH SYENITE 107 ACTIVE LODE CLAIM 9/3/2024 CA101490936 CA101490936 CAMC5985 CAMC5840 SYENITE 150 ACTIVE LODE CLAIM 9/3/2024 CA101490995 CA101490995 CAMC244772 CAMC244736 CMF 37 ACTIVE LODE CLAIM 9/3/2024 CA101491028 CA101491028 CAMC234483 CAMC234416 SYENITE 261 ACTIVE LODE CLAIM 9/3/2024 CA101491174 CA101491174 CAMC215723 CAMC215721 SYENITE 188 ACTIVE LODE CLAIM 9/3/2024 CA101491177 CA101491177 CAMC47647 CAMC47621 BAILEY 27 ACTIVE LODE CLAIM 9/3/2024 CA101491192 CA101491192 CAMC5860 CAMC5840 SYENITE 21 ACTIVE LODE CLAIM 9/3/2024 CA101491203 CA101491203 CAMC177669 CAMC177640 SOUTH ACTIVE LODE 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 15 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date SYENITE 30 CLAIM CA101491436 CA101491436 CAMC16264 CAMC16264 MINERAL HILL NO 1 ACTIVE LODE CLAIM 9/3/2024 CA101491526 CA101491526 CAMC177668 CAMC177640 SOUTH SYENITE 29 ACTIVE LODE CLAIM 9/3/2024 CA101491667 CA101491667 CAMC5867 CAMC5840 SYENITE 28 ACTIVE LODE CLAIM 9/3/2024 CA101491670 CA101491670 CAMC47621 CAMC47621 BAILEY 1 ACTIVE LODE CLAIM 9/3/2024 CA101491677 CA101491677 CAMC177661 CAMC177640 SOUTH SYENITE 22 ACTIVE LODE CLAIM 9/3/2024 CA101491831 CA101491831 CAMC177679 CAMC177640 SOUTH SYENITE 40 ACTIVE LODE CLAIM 9/3/2024 CA101492424 CA101492424 CAMC5969 CAMC5840 SYENITE 133 ACTIVE LODE CLAIM 9/3/2024 CA101492565 CA101492565 CAMC234462 CAMC234416 SYENITE 240 ACTIVE LODE CLAIM 9/3/2024 CA101492678 CA101492678 CAMC5932 CAMC5840 SYENITE 96 ACTIVE LODE CLAIM 9/3/2024 CA101492687 CA101492687 CAMC234451 CAMC234416 SYENITE 229 ACTIVE LODE CLAIM 9/3/2024 CA101492722 CA101492722 CAMC5898 CAMC5840 SYENITE 59 ACTIVE LODE CLAIM 9/3/2024 CA101492902 CA101492902 CAMC5996 CAMC5840 SYENITE 161 ACTIVE LODE CLAIM 9/3/2024 CA101493072 CA101493072 CAMC234452 CAMC234416 SYENITE 230 ACTIVE LODE CLAIM 9/3/2024 CA101493120 CA101493120 CAMC5893 CAMC5840 SYENITE 54 ACTIVE LODE CLAIM 9/3/2024 CA101493145 CA101493145 CAMC16266 CAMC16264 MINERAL HILL NO 3 ACTIVE LODE CLAIM 9/3/2024 CA101493146 CA101493146 CAMC6001 CAMC5840 SYENITE 166 FILED LODE CLAIM 9/3/2024 CA101493154 CA101493154 CAMC5843 CAMC5840 SYENITE 4 ACTIVE LODE CLAIM 9/3/2024 CA101493212 CA101493212 CAMC5922 CAMC5840 SYENITE 83 ACTIVE LODE CLAIM 9/3/2024 CA101493216 CA101493216 CAMC177699 CAMC177640 SOUTH SYENITE 60 ACTIVE LODE CLAIM 9/3/2024 CA101493241 CA101493241 CAMC244789 CAMC244736 CMF 54 ACTIVE LODE CLAIM 9/3/2024 CA101493406 CA101493406 CAMC5896 CAMC5840 SYENITE 57 ACTIVE LODE CLAIM 9/3/2024 CA101493425 CA101493425 CAMC234473 CAMC234416 SYENITE 251 ACTIVE LODE CLAIM 9/3/2024 CA101493430 CA101493430 CAMC5846 CAMC5840 SYENITE 7 ACTIVE LODE CLAIM 9/3/2024 CA101493730 CA101493730 CAMC51749 CAMC51692 LUCKY STRIKE NO 5 ACTIVE LODE CLAIM 9/3/2024 CA101493733 CA101493733 CAMC5863 CAMC5840 SYENITE 24 ACTIVE LODE CLAIM 9/3/2024 CA101493736 CA101493736 CAMC177689 CAMC177640 SOUTH ACTIVE LODE 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 16 of 21 DEPARTIRENT O F THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date SYENITE 50 CLAIM CA101493744 CA101493744 CAMC234420 CAMC234416 SYENITE 198 ACTIVE LODE CLAIM 9/3/2024 CA101493750 CA101493750 CAMC16265 CAMC16264 MINERAL HILL NO 2 ACTIVE LODE CLAIM 9/3/2024 CA101493760 CA101493760 CAMC234493 CAMC234416 SYENITE 271 ACTIVE LODE CLAIM 9/3/2024 CA101493764 CA101493764 CAMC177678 CAMC177640 SOUTH SYENITE 39 ACTIVE LODE CLAIM 9/3/2024 CA101494022 CA101494022 CAMC177658 CAMC177640 SOUTH SYENITE 19 ACTIVE LODE CLAIM 9/3/2024 CA101494024 CA101494024 CAMC5919 CAMC5840 SYENITE 80 ACTIVE LODE CLAIM 9/3/2024 CA101494125 CA101494125 CAMC234477 CAMC234416 SYENITE 255 ACTIVE LODE CLAIM 9/3/2024 CA101494154 CA101494154 CAMC5946 CAMC5840 SYENITE 110 ACTIVE LODE CLAIM 9/3/2024 CA101495479 CA101495479 CAMC244768 CAMC244736 CMF 33 ACTIVE LODE CLAIM 9/3/2024 CA101496241 CAIO1496241 CAMC5866 CAMC5840 SYENITE 27 ACTIVE LODE CLAIM 9/3/2024 CA101496271 CA101496271 CAMC177648 CAMC177640 SOUTH SYENITE 9 ACTIVE LODE CLAIM 9/3/2024 CA101496338 CA101496338 CAMC47648 CAMC47621 BAILEY 28 ACTIVE LODE CLAIM 9/3/2024 CA101496343 CA101496343 CAMC177671 CAMC177640 SOUTH SYENITE 32 ACTIVE LODE CLAIM 9/3/2024 CA101496578 CA101496578 CAMC177647 CAMC177640 SOUTH SYENITE 8 ACTIVE LODE CLAIM 9/3/2024 CA101496580 CA101496580 CAMC244779 CAMC244736 CMF 44 ACTIVE LODE CLAIM 9/3/2024 CA101496583 CA101496583 CAMC120582 CAMC120576 DESERT POPPY 6 ACTIVE LODE CLAIM 9/3/2024 CA101496892 CA101496892 CAMC234431 CAMC234416 SYENITE 209 ACTIVE LODE CLAIM 9/3/2024 CA101496894 CA101496894 CAMC5925 CAMC5840 SYENITE 86 ACTIVE LODE CLAIM 9/3/2024 CA101497039 CA101497039 CAMC233782 CAMC233774 SYENITE 184A ACTIVE LODE CLAIM 9/3/2024 CA101497041 CA101497041 CAMC47651 CAMC47621 BAILEY 31 ACTIVE LODE CLAIM 9/3/2024 CA101497524 CA101497524 CAMC5935 CAMC5840 SYENITE 99 ACTIVE LODE CLAIM 9/3/2024 CA101497746 CA101497746 CAMC244737 CAMC244736 CMF 2 ACTIVE LODE CLAIM 9/3/2024 CA101498009 CA101498009 CAMC244793 CAMC244736 CMF 58 ACTIVE LODE CLAIM 9/3/2024 CA101498219 CA101498219 CAMC234435 CAMC234416 SYENITE 213 ACTIVE LODE CLAIM 9/3/2024 CA101498832 CA101498832 CAMC5854 CAMC5840 SYENITE 15 ACTIVE LODE CLAIM 9/3/2024 CA101526286 CA101526286 CAMC234456 CAMC234416 SYENITE 234 ACTIVE LODE 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 17 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CLAIM CA101540601 CA101540601 CAMC245124 CAMC245118 SOUTH SYENITE 113 ACTIVE LODE CLAIM 9/3/2024 CA101540603 CA101540603 CAMC244743 CAMC244736 CMF 8 ACTIVE LODE CLAIM 9/3/2024 CA101540721 CA101540721 CAMC234479 CAMC234416 SYENITE 257 ACTIVE LODE CLAIM 9/3/2024 CA101540725 CA101540725 CAMC5856 CAMC5840 SYENITE 17 ACTIVE LODE CLAIM 9/3/2024 CA101540729 CA101540729 CAMC5929 CAMC5840 SYENITE 189 ACTIVE LODE CLAIM 9/3/2024 CA101540861 CA101540861 CAMC244784 CAMC244736 CMF 49 ACTIVE LODE CLAIM 9/3/2024 CA101542063 CA101542063 CAMC47643 CAMC47621 BAILEY 23 ACTIVE LODE CLAIM 9/3/2024 CA101542115 CA101542115 CAMC245125 CAMC245118 SOUTH SYENITE 114 ACTIVE LODE CLAIM 9/3/2024 CA101542123 CA101542123 CAMC51706 CAMC51692 CLARK MOUNTAIN NO 24 ACTIVE LODE CLAIM 9/3/2024 CA101542169 CA101542169 CAMC47644 CAMC47621 BAILEY 24 ACTIVE LODE CLAIM 9/3/2024 CA101542206 CA101542206 CAMC234458 CAMC234416 SYENITE 236 ACTIVE LODE CLAIM 9/3/2024 CA101542264 CA101542264 CAMC177643 CAMC177640 SOUTH SYENITE 4 ACTIVE LODE CLAIM 9/3/2024 CA101543402 CA101543402 CAMC201791 CAMC201787 SYENITE 95 ACTIVE LODE CLAIM 9/3/2024 CA101543403 CA101543403 CAMC177673 CAMC177640 SOUTH SYENITE 34 ACTIVE LODE CLAIM 9/3/2024 CA101543429 CA101543429 CAMC47676 CAMC47621 BAILEY 65 ACTIVE LODE CLAIM 9/3/2024 CA101543539 CA101543539 CAMC5975 CAMC5840 SYENITE 139 ACTIVE LODE CLAIM 9/3/2024 CA101543575 CA101543575 CAMC244753 CAMC244736 CMF 18 ACTIVE LODE CLAIM 9/3/2024 CA101544613 CA101544613 CAMC177663 CAMC177640 SOUTH SYENITE 24 ACTIVE LODE CLAIM 9/3/2024 CA101544615 CA101544615 CAMC5961 CAMC5840 SYENITE 125 ACTIVE LODE CLAIM 9/3/2024 CA101544667 CA101544667 CAMC5885 CAMC5840 SYENITE 46 ACTIVE LODE CLAIM 9/3/2024 CA101544668 CA101544668 CAMC5954 CAMC5840 SYENITE 118 ACTIVE LODE CLAIM 9/3/2024 CA101544694 CA101544694 CAMC244786 CAMC244736 CMF 51 ACTIVE LODE CLAIM 9/3/2024 CA101544955 CA101544955 CAMC234416 CAMC234416 SYENITE 194 ACTIVE LODE CLAIM 9/3/2024 CA101545807 CA101545807 CAMC5911 CAMC5840 SYENITE 72 ACTIVE LODE CLAIM 9/3/2024 CA101547304 CA101547304 CAMC244755 CAMC244736 CMF 20 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 18 of 21 DEPARTS ENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101547435 CA101547435 CAMC177642 CAMC177640 SOUTH SYENITE 3 ACTIVE LODE CLAIM 9/3/2024 CA101547436 CA101547436 CAMC244774 CAMC244736 CMF 39 ACTIVE LODE CLAIM 9/3/2024 CA101547625 CA101547625 CAMC245123 CAMC245118 SOUTH SYENITE 112 ACTIVE LODE CLAIM 9/3/2024 CA101548828 CA101548828 CAMC177653 CAMC177640 SOUTH SYENITE 14 ACTIVE LODE CLAIM 9/3/2024 CA101548940 CA101548940 CAMC5883 CAMC5840 SYENITE 44 ACTIVE LODE CLAIM 9/3/2024 CA101550011 CA101550011 CAMC177670 CAMC177640 SOUTH SYENITE 31 ACTIVE LODE CLAIM 9/3/2024 CA101550031 CA101550031 CAMC5904 CAMC5840 SYENITE 65 ACTIVE LODE CLAIM 9/3/2024 CA101550111 CA101550111 CAMC5965 CAMC5840 SYENITE 129 ACTIVE LODE CLAIM 9/3/2024 CA101600612 CA101600612 CAMC244787 CAMC244736 CMF 52 ACTIVE LODE CLAIM 9/3/2024 CA101600620 CA101600620 CAMC47657 CAMC47621 BAILEY 37 ACTIVE LODE CLAIM 9/3/2024 CA101600722 CA101600722 CAMC234480 CAMC234416 SYENITE 258 ACTIVE LODE CLAIM 9/3/2024 CA101600728 CA101600728 CAMC47632 CAMC47621 BAILEY 12 ACTIVE LODE CLAIM 9/3/2024 CA101600768 CA101600768 CAMC5970 CAMC5840 SYENITE 134 ACTIVE LODE CLAIM 9/3/2024 CA101600771 CA101600771 CAMC5881 CAMC5840 SYENITE 42 ACTIVE LODE CLAIM 9/3/2024 CA101600946 CA101600946 CAMC47636 CAMC47621 BAILEY 16 ACTIVE LODE CLAIM 9/3/2024 CA101601067 CA101601067 CAMC5957 CAMC5840 SYENITE 121 ACTIVE LODE CLAIM 9/3/2024 CA101601216 CA101601216 CAMC47642 CAMC47621 BAILEY 22 ACTIVE LODE CLAIM 9/3/2024 CA101601219 CA101601219 CAMC247588 CAMC247586 CMF 72 ACTIVE LODE CLAIM 9/3/2024 CA101601292 CA101601292 CAMC177686 CAMC177640 SOUTH SYENITE 47 ACTIVE LODE CLAIM 9/3/2024 CA101601378 CA101601378 CAMC234417 CAMC234416 SYENITE 195 ACTIVE LODE CLAIM 9/3/2024 CA101601601 CA101601601 CAMC245126 CAMC245118 SOUTH SYENITE 115 ACTIVE LODE CLAIM 9/3/2024 CA101601603 CA101601603 CAMC244745 CAMC244736 CMF 10 ACTIVE LODE CLAIM 9/3/2024 CA101601835 CA101601835 CAMC5937 CAMC5840 SYENITE 101 ACTIVE LODE CLAIM 9/3/2024 CA101601873 CA101601873 CAMC244756 CAMC244736 CMF 21 ACTIVE LODE CLAIM 9/3/2024 CA101601922 CA101601922 CAMC47673 CAMC47621 BAILEY 62 ACTIVE LODE CLAIM 9/3/2024 CA101602001 CA101602001 CAMC5927 CAMC5840 SYENITE 88 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 19 of 21 DEPARTSMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101602004 CA101602004 CAMC177665 CAMC177640 SOUTH SYENITE 26 ACTIVE LODE CLAIM 9/3/2024 CA101602121 CA101602121 CAMC177654 CAMC177640 SOUTH SYENITE 15 ACTIVE LODE CLAIM 9/3/2024 CA101603434 CA101603434 CAMC215722 CAMC215721 SYENITE 187 ACTIVE LODE CLAIM 9/3/2024 CA101603492 CA101603492 CAMC51741 CAMC51692 EARL NO 3 ACTIVE LODE CLAIM 9/3/2024 CA101606407 CA101606407 CAMC5943 CAMC5840 SYENITE 107 ACTIVE LODE CLAIM 9/3/2024 CA101606408 CA101606408 CAMC47649 CAMC47621 BAILEY 29 ACTIVE LODE CLAIM 9/3/2024 CA101609046 CA101609046 CAMC5973 CAMC5840 SYENITE 137 ACTIVE LODE CLAIM 9/3/2024 CA101609679 CA101609679 CAMC234476 CAMC234416 SYENITE 254 ACTIVE LODE CLAIM 9/3/2024 CA101610219 CA101610219 CAMC5993 CAMC5840 SYENITE 158 ACTIVE LODE CLAIM 9/3/2024 CA101730629 CA101730629 CAMC244751 CAMC244736 CMF 16 ACTIVE LODE CLAIM 9/3/2024 CA101751224 CA101751224 CAMC5984 CAMC5840 SYENITE 149 ACTIVE LODE CLAIM 9/3/2024 CA101751226 CA101751226 CAMC5899 CAMC5840 SYENITE 60 ACTIVE LODE CLAIM 9/3/2024 CA101751235 CA101751235 CAMC5849 CAMC5840 SYENITE 10 ACTIVE LODE CLAIM 9/3/2024 CA101751261 CA101751261 CAMC47675 CAMC47621 BAILEY 64 ACTIVE LODE CLAIM 9/3/2024 CA101751510 CA101751510 CAMC47641 CAMC47621 BAILEY 21 ACTIVE LODE CLAIM 9/3/2024 CA101751521 CA101751521 CAMC47634 CAMC47621 BAILEY 14 ACTIVE LODE CLAIM 9/3/2024 CA101751627 CA101751627 CAMC177662 CAMC177640 SOUTH SYENITE 23 ACTIVE LODE CLAIM 9/3/2024 CA101752643 CA101752643 CAMC47668 CAMC47621 BAILEY 55 ACTIVE LODE CLAIM 9/3/2024 CA101754007 CA101754007 CAMC5886 CAMC5840 SYENITE 47 ACTIVE LODE CLAIM 9/3/2024 CA101754010 CA101754010 CAMC5959 CAMC5840 SYENITE 123 ACTIVE LODE CLAIM 9/3/2024 CA101754125 CA101754125 CAMC47666 CAMC47621 BAILEY 53 ACTIVE LODE CLAIM 9/3/2024 CA101754177 CA101754177 CAMC234437 CAMC234416 SYENITE 215 ACTIVE LODE CLAIM 9/3/2024 CA101755423 CA101755423 CAMC5855 CAMC5840 SYENITE 16 ACTIVE LODE CLAIM 9/3/2024 CA101755425 CA101755425 CAMC5924 CAMC5840 SYENITE 85 ACTIVE LODE CLAIM 9/3/2024 CA101755430 CA101755430 CAMC177745 CAMC177640 SOUTH SYENITE 106 ACTIVE LODE CLAIM 9/3/2024 CA101755495 CA101755495 CAMC244795 CAMC244736 CMF 60 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 20 of 21 DEPARTMENT O F THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due Date CA101755519 CA101755519 CAMC247587 CAMC247586 CMF 71 ACTIVE LODE CLAIM 9/3/2024 CA101756663 CA101756663 CAMC247589 CAMC247586 CMF 73 ACTIVE LODE CLAIM 9/3/2024 CA101756696 CA101756696 CAMC177652 CAMC177640 SOUTH SYENITE 13 ACTIVE LODE CLAIM 9/3/2024 CA101756700 CA101756700 CAMC5909 CAMC5840 SYENITE 70 ACTIVE LODE CLAIM 9/3/2024 CA101756843 CA101756843 CAMC5915 CAMC5840 SYENITE 76 ACTIVE LODE CLAIM 9/3/2024 CA101756918 CA101756918 CAMC5958 CAMC5840 SYENITE 122 ACTIVE LODE CLAIM 9/3/2024 CA101758021 CA101758021 CAMC5934 CAMC5840 SYENITE 98 ACTIVE LODE CLAIM 9/3/2024 CA101758025 CA101758025 CAMC244797 CAMC244736 CMF 62 ACTIVE LODE CLAIM 9/3/2024 CA101758030 CA101758030 CAMC47658 CAMC47621 BAILEY 38 ACTIVE LODE CLAIM 9/3/2024 CA101758039 CA101758039 CAMC234439 CAMC234416 SYENITE 217 ACTIVE LODE CLAIM 9/3/2024 CA101758310 CA101758310 CAMC177674 CAMC177640 SOUTH SYENITE 35 ACTIVE LODE CLAIM 9/3/2024 CA101758313 CAI01758313 CAMC5908 CAMC5840 SYENITE 69 ACTIVE LODE CLAIM 9/3/2024 CA101759275 CA101759275 CAMC47672 CAMC47621 BAILEY 59 ACTIVE LODE CLAIM 9/3/2024 CA101759276 CA101759276 CAMC47627 CAMC47621 BAILEY 7 ACTIVE LODE CLAIM 9/3/2024 CA101759484 CA101759484 CAMC47659 CAMC47621 BAILEY 39 ACTIVE LODE CLAIM 9/3/2024 CA101759521 CAIO1759521 CAMC177664 CAMC177640 SOUTH SYENITE 25 ACTIVE LODE CLAIM 9/3/2024 CA101759615 CA101759615 CAMC101865 CAMC101865 SYENITE #177 ACTIVE LODE CLAIM 9/3/2024 CA101759617 CA101759617 CAMC213564 CAMC213564 EAST SYENITE #2 ACTIVE LODE CLAIM 9/3/2024 CA101759661 CA101759661 CAMC47638 CAMC47621 BAILEY 18 ACTIVE LODE CLAIM 9/3/2024 CA101759673 CA101759673 CAMC47645 CAMC47621 BAILEY 25 ACTIVE LODE CLAIM 9/3/2024 CA101780868 CA101780868 CAMC177650 CAMC177640 SOUTH SYENITE 11 ACTIVE LODE CLAIM 9/3/2024 CA102493275 CA102493275 CAMC5964 CAMC5840 SYENITE 128 CLOSED LODE CLAIM CA102520546 CA102520546 CAMC234463 CAMC234416 SYENITE 241 ACTIVE LODE CLAIM 9/3/2024 CA102521164 CA102521164 CAMC201787 CAMC201787 SYENITE 71 ACTIVE LODE CLAIM 9/3/2024 CA102521176 CA102521176 CAMC234484 CAMC234416 SYENITE 262 ACTIVE LODE CLAIM 9/3/2024 CA102521342 CA102521342 CAMC177659 CAMC177640 SOUTH SYENITE 20 ACTIVE LODE CLAIM 9/3/2024 NO WARRANTY IS MADE BY BLM FOR USE OF THE DATA FOR PURPOSES NOT INTENDED BY BLM

February 2024

SRK Consulting (U.S.), Inc.
SEC Technical Report Summary – Mountain Pass Mine	Appendices

Date and Time Run: 10/4/2023 7:29:38 PM Page 21 of 21 DEPARTMENT OF THE INTERIOR BUREAU OF LAND MANAGEMENT MINING CLAIMS Serial Number Lead File Number Legacy Serial Number Legacy Lead File Number Claim Name Case Disposition Claim Type Next Payment Due â–¡ate CA102521349 CA102521349 CAMC5968 CAMC5840 SYENITE 132 ACTIVE LODE CLAIM 9/3/2024 CA102521367 CA102521367 CAMC234422 CAMC234416 SYENITE 200 ACTIVE LODE CLAIM 9/3/2024 CA102521371 CA102521371 CAMC234443 CAMC234416 SYENITE 221 ACTIVE LODE CLAIM 9/3/2024

February 2024