Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of the Company’s Consolidated Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include inventories; mineral reserves and resources; long-lived asset impairments; reclamation obligations; post-employment and other employee benefit obligations; useful lives, depletion and amortization; reserves for workers’ compensation and black lung claims; deferred income taxes; income taxes payable; income taxes refundable and receivable; reserves for contingencies and litigation; and fair value of financial instruments. Estimates are based on facts and circumstances believed to be reasonable at the time; however, actual results could differ from those estimates. Cash and Cash Equivalents Cash and cash equivalents consist of cash held with reputable depository institutions and highly liquid, short-term investments, such as highly-rated money market funds, with original maturities of three months or less. Cash and cash equivalents are stated at cost, which approximates fair value. Restricted Cash Amounts included in restricted cash represent cash and cash equivalents that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure the certain obligations which have been written on the Company’s behalf. Refer to Note 21 for further information. Investments Short-term investments consist of U.S government securities. Restricted investments consist of Federal Deposit Insurance Company (“FDIC”) insured certificates of deposit, corporate fixed income, and U.S. government securities that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure certain obligations which have been written on the Company’s behalf. All investments are classified as trading securities as of December 31, 2023 and 2022. Trading securities are recorded initially at cost and are adjusted to fair value at each reporting period with unrealized gains and losses recorded in current period earnings or loss. Refer to Note 21 for further information. Deposits Deposits represent cash deposits held at third parties as required by certain agreements entered into by the Company to provide cash collateral to secure the following obligations which have been written on the Company’s behalf. Refer to Note 21 for further information. Trade Accounts Receivable and Allowance for Credit Losses Trade accounts receivable are recorded at their invoiced amounts and do not bear interest. The Company markets its coal primarily to international and domestic steel producers and electric utilities in the United States. Credit is extended based on an evaluation of a customer’s financial condition, including a review of third-party credit score information. Collateral is generally not required. Accounts receivable balances are monitored against approved credit limits. Credit limits are monitored and adjusted as considered necessary based on changes to a customer’s credit profile. If a customer’s credit deteriorates, the Company may reduce credit risk exposure by reducing credit limits, obtaining letters of credit (“LCs”), obtaining credit insurance, or requiring pre-payment for shipments. Credit losses have historically not been material. Account balances are written-off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. Refer to Note 22 for further information. Inventories Coal is reported as inventory at the point in time the coal is extracted from the mine. Raw coal represents coal stockpiles that may be sold in current condition or may be further processed prior to shipment to a customer. Saleable coal represents coal stockpiles that require no further processing prior to shipment to a customer. Coal inventories are valued at the lower of average cost or net realizable value. The cost of coal inventories is determined based on the average cost of production, which includes labor, supplies, equipment costs, operating overhead, depreciation, and other related costs. Net realizable value considers the projected future sales price of the product, less estimated preparation and selling costs. Material and supplies inventories are valued at average cost, less an allowance for obsolete and surplus items. Refer to Note 6 for further information. Advanced Mining Royalties Lease rights to coal reserves are often acquired in exchange for royalty payments. Advanced mining royalties are advanced payments made to lessors under terms of mineral lease agreements that are recoupable against future production royalties. These advanced payments are deferred and charged to operations as the coal reserves are mined. The Company regularly reviews recoverability of advanced mining royalties and establishes or adjusts the allowance for advanced mining royalties as necessary using the specific identification method. Advanced royalty balances are generally charged off against the allowance when they are no longer recoupable. Advanced mining royalties are included within Other non-current assets on the Company’s Consolidated Balance Sheets. Refer to Note 9 for further information. Property, Plant, and Equipment, Net Costs for mine development incurred to expand capacity of operating mines or to develop new mines are capitalized and charged to operations on the units-of-production method over the estimated proven and probable reserve tons directly benefiting from the capital expenditures. Mine development costs include costs incurred for site preparation and development of the mines during the development stage less any incidental revenue generated during the development stage. Mining equipment, buildings, and other fixed assets are stated at cost and depreciated on a straight-line basis over estimated useful lives ranging from one to 25 years. Leasehold improvements are amortized using the straight-line method, over the shorter of the estimated useful lives or term of the lease. Major repairs and betterments that significantly extend original useful lives or improve productivity are capitalized and depreciated over the period benefited. Maintenance and repairs are expensed as incurred. When equipment is retired or disposed, the related cost and accumulated depreciation are removed from the respective accounts and any profit or loss on disposal is recognized in Other (income) expense in the Company’s Consolidated Statements of Operations. Refer to Note 8 for further information. Owned and Leased Mineral Rights Owned and leased mineral rights, net of accumulated depletion and amortization, for the years ended December 31, 2023 and 2022 were $451,160 and $451,062, respectively, and are reported in assets in the Company’s Consolidated Balance Sheets. These amounts include $27,473 and $20,284 of asset retirement obligation assets, net of accumulated amortization, associated with active mining operations for the years ended December 31, 2023 and 2022, respectively. Costs to obtain owned and leased mineral rights are capitalized and amortized to operations as depletion expense using the units-of-production method. Only proven and probable reserves are included in the depletion base. Depletion expense is included in Depreciation, depletion and amortization in the accompanying Consolidated Statements of Operations and was $23,944, $23,078, and $23,541 for the years ended December 31, 2023, 2022, and 2021 respectively. Depletion expense for the years ended December 31, 2023, 2022, and 2021 includes a credit of ($34), a credit of ($3,016), and an expense of $5,782, respectively, related to revisions to asset retirement obligations. Refer to Note 15 for further disclosures related to asset retirement obligations. Leases In accordance with ASC 842, the Company recognizes right of use assets and lease liabilities on the Consolidated Balance Sheets for all leases with a term longer than 12 months. Some of these leases include both lease and non-lease components which are accounted for as a single lease component as the Company has elected the practical expedient to combine these components for all leases. The discount rates used to determine the present value of the lease assets and liabilities are based on the Company’s incremental borrowing rate at the lease commencement date and commensurate with the remaining lease term. As the rates implicit in most of the Company’s leases are not readily determinable, the Company uses a collateralized incremental borrowing rate based on the information available at the lease commencement date in determining the present value of future payments. The Company uses the portfolio approach and groups leases by short-term and long-term categories, applying the corresponding incremental borrowing rates to these categories of leases. For leases with a term of 12 months or less, no right of use assets or liabilities are recognized on the Consolidated Balance Sheets and the Company recognizes the lease expense on a straight-line basis over the lease term. Additionally, the Company recognizes variable lease payments as an expense in the period incurred. The Company has elected to show net instead of gross amounts for right-of-use assets and liabilities within its Consolidated Statements of Cash Flows. Refer to Note 11 for further information. Acquired Intangibles The Company has recognized assets for acquired mine permits which were valued based on the replacement cost and lost profits method as of the Merger date. The balances of such assets as of December 31, 2023 and 2022, net of accumulated amortization, were $46,579 and $55,102, respectively, and are included within Other acquired intangibles, net of accumulated amortization, on the Company’s Consolidated Balance Sheets. The acquired mine permits are amortized over the estimated life of the associated mine. Amortization expense is included in Amortization of acquired intangibles, net in the accompanying Consolidated Statements of Operations and was $8,523, $19,498, and $13,571 for the years ended December 31, 2023, 2022, and 2021, respectively. Additionally, the Company previously recognized assets for acquired above market-priced coal supply agreements and liabilities for acquired below market-priced coal supply agreements. The agreements were amortized over the actual number of tons shipped over the life of each contract. Amortization expense is included in Amortization of acquired intangibles, net in the accompanying Consolidated Statements of Operations and was $0, $0, and ($327) for the years ended December 31, 2023, 2022, and 2021, respectively. Future net amortization expense related to acquired intangibles is expected to be $6,703, $5,892, $5,373, $4,790, $4,790, and $19,031 for 2024, 2025, 2026, 2027, 2028, and after 2028, respectively. Goodwill Goodwill represents the excess of the purchase price over the fair value of the net identifiable tangible and intangible assets of acquired companies. Goodwill for the years ended December 31, 2023 and 2022 was $11,124 and $10,736, respectively, and is included within Other non-current assets on the Company’s Consolidated Balance Sheets. In January 2023, primarily to secure additional coal trucks and related equipment and facilities, the Company purchased substantially all the assets of a freight, hauling and transportation services business for $11,919, resulting in $388 of goodwill. The acquired goodwill, related primarily to the acquired workforce and expected cost synergies, was allocated to the Company's Met reportable segment. In December 2022, the Company purchased substantially all of the assets of a mining equipment component manufacturing and rebuild business to help secure the supply of certain underground mining equipment parts needed for the Company’s operations for $24,878, which included $7,787 of working capital, $6,355 of property, plant, and equipment, and $10,736 of goodwill. The acquired goodwill, related primarily to the acquired workforce and expected cost synergies, was allocated to the Company’s Met reportable segment. Goodwill is not amortized; instead, it is tested for impairment annually as of October 31 of each year or more frequently if indicators of impairment exist. The Company assesses goodwill for impairment on a qualitative basis. If the Company determines that more likely than not the fair value of a reporting unit containing goodwill exceeds its carrying amount, no further impairment testing is required. If the qualitative assessment indicates that an impairment potentially exists, then the Company quantitatively tests goodwill for impairment by comparing the fair value of the reporting unit to its carrying amount. If the fair value of the reporting unit is lower than its carrying amount, its goodwill is written down by the lesser of the amount by which the reporting units carrying amount exceeded its fair value or its carrying amount of goodwill. Asset Impairment Long-lived assets, such as property, plant, and equipment, mineral rights, and acquired intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset groups may not be recoverable. Recoverability of assets or asset groups to be held and used is measured by a comparison of the carrying amount of an asset or asset group to the estimated undiscounted future cash flows expected to be generated by the asset or asset group. Long-lived assets located in a close geographic area are grouped together for purposes of impairment testing when, after considering revenue and cost interdependencies, circumstances indicate the assets are used together to produce future cash flows. The Company’s asset groups generally consist of the assets and applicable liabilities of one or more mines and preparation plants and associated coal reserves for which cash flows are largely independent of cash flows of other mines, preparation plants, and associated coal reserves. If the carrying amount of an asset or asset group exceeds its estimated future cash flows, the potential impairment is equal to the amount by which the carrying amount of the asset or asset group exceeds the fair value of the asset or asset group. The Company estimates the fair value of an asset group generally using discounted cash flow analysis based on estimates of future sales volumes, coal prices, production costs, and a risk-adjusted cost of capital. These estimates generally constitute unobservable Level 3 inputs under the fair value hierarchy. The amount of impairment, if any, is allocated to the long-lived assets on a pro-rata basis, except that the carrying value of the individual long-lived assets are not reduced below their estimated fair value. Asset Retirement Obligations Minimum standards for mine reclamation have been established by various regulatory agencies and dictate the reclamation requirements at the Company’s operations. The Company’s asset retirement obligations consist principally of costs to reclaim acreage disturbed at surface operations and estimated costs to reclaim support acreage, treat mine water discharge, and perform other related functions at underground mines. The Company records these reclamation obligations at fair value in the period in which the legal obligation associated with the retirement of the long-lived asset is incurred. Changes to the liability at operations that are not currently being reclaimed are offset by increasing or decreasing the carrying amount of the related long-lived asset. Changes to the liability at operations that are currently being reclaimed are recorded to Depreciation, depletion, and amortization. Over time, the liability is accreted and any capitalized cost is depreciated or depleted over the useful life of the related asset. To settle the liability, the obligation is paid, and any difference between the liability and the amount of cash paid is recorded within Depreciation, depletion and amortization within the Consolidated Statements of Operations at the time the reclamation work is completed. On at least an annual basis, the Company reviews its estimated future cash flows for its asset retirement obligations. Refer to Note 15 for further information. Income Taxes The Company recognizes deferred tax assets and liabilities using enacted tax rates for the effect of temporary differences between the book and tax bases of recorded assets and liabilities. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized. In evaluating its ability to recover deferred tax assets within the jurisdiction in which they arise, the Company considers all available positive and negative evidence, including the expected reversals of deferred tax liabilities, projected future taxable income, taxable income available via carryback to prior years, tax planning strategies, and results of recent operations. The Company assesses the realizability of its deferred tax assets, including scheduling the reversal of its deferred tax assets and liabilities, to determine the amount of valuation allowance needed. Scheduling the reversal of deferred tax asset and liability balances requires judgment and estimation. The Company believes the deferred tax liabilities relied upon as future taxable income in its assessment will reverse in the same period and jurisdiction and are of the same character as the temporary differences giving rise to the deferred tax assets that will be realized. Refer to Note 17 for further information. Deferred Financing Costs The costs to obtain new debt financing or amend existing financing agreements are generally deferred and amortized to interest expense over the life of the related indebtedness or credit facility using the effective interest method. Unamortized deferred financing costs are presented in the Consolidated Balance Sheets as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts or premiums. Unamortized deferred financing costs associated with undrawn credit facilities are included in the Consolidated Balance Sheets within Other non-current assets. Revenue Recognition In accordance with ASC 606 Revenue from Contracts with Customers (“ASC 606”), the Company measures revenue based on the consideration specified in a contract with a customer and recognizes revenue as a result of satisfying its promise to transfer goods or services in a contract with a customer using the following general revenue recognition five-step model: (1) identify the contract; (2) identify performance obligations; (3) determine transaction price; (4) allocate transaction price; and (5) recognize revenue. Freight and handling costs paid to third-party carriers and invoiced to coal customers are recorded as freight and handling costs and freight and handling fulfillment revenues within cost of coal sales and coal revenues, respectively. Refer to Note 3 for further information. Workers’ Compensation and Pneumoconiosis (Black Lung) Benefits Workers’ Compensation As of December 31, 2023, the Company’s subsidiaries generally utilize high-deductible insurance programs for workers’ compensation claims at its operations with the exception of certain subsidiaries in which the Company is a qualified self-insurer for workers’ compensation obligations. The liabilities for workers’ compensation claims are estimates of the ultimate losses incurred based on the Company’s experience and include a provision for incurred but not reported losses. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These short-term and long-term obligations are included in the Consolidated Balance Sheets within Accrued expenses and other current liabilities and Workers’ compensation and black lung obligations, respectively, with the related expected insurance receivables within Prepaid expenses and other current assets and Other non-current assets. As of December 31, 2023 and 2022, the workers’ compensation liability was net of a discount of $22,205 and $22,824, respectively, related to fair value adjustments associated with acquisition accounting. Refer to Note 18 for further information. Black Lung Benefits The Company is required by federal and state statutes to provide benefits to employees for awards related to black lung. As of December 31, 2023, certain of the Company’s subsidiaries are insured for black lung obligations by a third-party insurance provider and certain subsidiaries are self-insured for state black lung obligations. Certain other subsidiaries are self-insured for federal black lung benefits and may fund benefit payments through a Section 501(c)(21) tax-exempt trust fund. Charges are made to operations for black lung claims, as determined by an independent actuary at the present value of the actuarially computed liability for such benefits over the employee’s applicable term of service. The Company recognizes in its Consolidated Balance sheets the amount of the Company’s unfunded Accumulated Benefit Obligation (“ABO”) at the end of the year. The actuarial gains and losses recognized in accumulated other comprehensive income (loss) are amortized into components of net periodic benefit cost over the expected lifetime of active participants (the Company does not use a corridor method). These short-term and long-term obligations are included in the Consolidated Balance Sheets within Accrued expenses and other current liabilities and Workers’ compensation and black lung obligations, respectively. Refer to Note 18 for further information. Pension The Company is required to recognize the overfunded or underfunded status of a defined benefit pension plan as an asset or liability in its Consolidated Balance Sheets and to recognize changes in that funded status in the year in which the changes occur through other comprehensive (loss) income. The actuarial gains and losses recognized in accumulated other comprehensive income (loss) are amortized into components of net periodic benefit cost over the average future lifetime of participants expected to have benefits (the Company does not use a corridor method). The Company is required to measure plan assets and benefit obligations as of the date of the Company’s fiscal year-end Consolidated Balance Sheet and provide the required disclosures as of the end of each fiscal year. Refer to Note 18 for information. Postretirement Life Insurance Benefits As part of the Alpha Natural Resources, Inc. bankruptcy reorganization plan and the Retiree Committee Settlement Agreement, the Company assumed the liability for life insurance benefits for certain disabled and non-union retired employees. Provisions are made for estimated benefits based on annual evaluations prepared by independent actuaries. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These obligations are included in the Consolidated Balance Sheets as Accrued expenses and other current liabilities and Other non-current liabilities. Refer to Note 18 for further information. Net Income per Share Basic net income per share is computed by dividing net income by the weighted-average number of outstanding common shares for the period. Diluted earnings per share reflects the potential dilution that could occur if instruments that may require the issuance of common shares in the future were settled and the underlying common shares were issued. Diluted earnings per share is computed by increasing the weighted-average number of outstanding common shares computed in basic earnings per share to include the additional common shares that would be outstanding after issuance and adjusting net income for changes that would result from the issuance. Only those securities that are dilutive are included in the calculation. In periods of loss, the number of shares used to calculate diluted earnings is the same as basic earnings per share. Refer to Note 5 for further information. Stock-Based Compensation The Company recognizes expense for stock-based compensation awards based on their grant-date fair value. The expense is recorded over the respective service period of the underlying award. Liability classified stock-based compensation awards are remeasured each reporting period at fair value until the award is settled. The Company recognizes forfeitures of stock-based compensation awards as they occur. Refer to Note 19 for further information. Warrants On July 26, 2016 (the “Initial Issue Date”), the Company issued warrants, which were classified as equity instruments, and were exercisable for cash or on a cashless basis at any time from the Initial Issue Date until July 26, 2023, and no fractional shares were issued upon warrant exercises. The exercise price and the warrant share number were adjusted in respect of certain dilutive events with respect to common stock. At 5:00 pm Eastern time on July 26, 2023 the Company’s Series A Warrants expired pursuant to their terms. Refer to Note 7 for additional information. Equity Method Investments Investments and membership interests in joint ventures are accounted for under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. Under the equity method of accounting, the Company’s proportionate share of the entity’s comprehensive income or loss each reporting period is reflected in Equity loss in affiliates in the Consolidated Statements of Operations. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable. The carrying values of the Company’s equity method investments are included within Other non-current assets on the Company’s Consolidated Balance Sheets. Refer to Notes 9 and 10 for additional information. Recent Accounting Guidance Segment Disclosures: In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). This update requires public entities to disclose significant segment expenses that are regularly provided to its chief operating decision maker and other segment items and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. The additional disclosures are required to be provided on a retrospective basis. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. The Company will provide the additional required disclosures upon adoption. Income Tax Disclosures: In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). This update requires public business entities to disclose in their income tax rate reconciliation table additional categories of information about federal, state, and foreign income taxes and to provide additional details about the reconciling items in categories meeting a quantitative threshold. The guidance will also require entities to disclose income taxes paid, net of refunds, disaggregated by federal, state, and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold. The additional disclosures are required to be provided on a prospective basis with the option to provide retrospectively. The amendments are effective for fiscal years beginning after December 15, 2024. The Company will provide the additional required disclosures upon adoption.

The preparation of the Company’s Consolidated Financial Statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the Consolidated Financial Statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates and assumptions include inventories; mineral reserves and resources; long-lived asset impairments; reclamation obligations; post-employment and other employee benefit obligations; useful lives, depletion and amortization; reserves for workers’ compensation and black lung claims; deferred income taxes; income taxes payable; income taxes refundable and receivable; reserves for contingencies and litigation; and fair value of financial instruments. Estimates are based on facts and circumstances believed to be reasonable at the time; however, actual results could differ from those estimates.

Short-term investments consist of U.S government securities. Restricted investments consist of Federal Deposit Insurance Company (“FDIC”) insured certificates of deposit, corporate fixed income, and U.S. government securities that are restricted as to withdrawal as required by certain agreements entered into by the Company and provide collateral to secure certain obligations which have been written on the Company’s behalf.

Trade accounts receivable are recorded at their invoiced amounts and do not bear interest. The Company markets its coal primarily to international and domestic steel producers and electric utilities in the United States. Credit is extended based on an evaluation of a customer’s financial condition, including a review of third-party credit score information. Collateral is generally not required. Accounts receivable balances are monitored against approved credit limits. Credit limits are monitored and adjusted as considered necessary based on changes to a customer’s credit profile. If a customer’s credit deteriorates, the Company may reduce credit risk exposure by reducing credit limits, obtaining letters of credit (“LCs”), obtaining credit insurance, or requiring pre-payment for shipments. Credit losses have historically not been material. Account balances are written-off against the allowance after all means of collection have been exhausted and the potential for recovery is considered remote. Refer to Note 22 for further information.

Coal inventories are valued at the lower of average cost or net realizable value. The cost of coal inventories is determined based on the average cost of production, which includes labor, supplies, equipment costs, operating overhead, depreciation, and other related costs. Net realizable value considers the projected future sales price of the product, less estimated preparation and selling costs. Material and supplies inventories are valued at average cost, less an allowance for obsolete and surplus items. Refer to Note 6 for further information.

Lease rights to coal reserves are often acquired in exchange for royalty payments. Advanced mining royalties are advanced payments made to lessors under terms of mineral lease agreements that are recoupable against future production royalties. These advanced payments are deferred and charged to operations as the coal reserves are mined. The Company regularly reviews recoverability of advanced mining royalties and establishes or adjusts the allowance for advanced mining royalties as necessary using the specific identification method. Advanced royalty balances are generally charged off against the allowance when they are no longer recoupable. Advanced mining royalties are included within Other non-current assets on the Company’s Consolidated Balance Sheets. Refer to Note 9 for further information.

Costs for mine development incurred to expand capacity of operating mines or to develop new mines are capitalized and charged to operations on the units-of-production method over the estimated proven and probable reserve tons directly benefiting from the capital expenditures. Mine development costs include costs incurred for site preparation and development of the mines during the development stage less any incidental revenue generated during the development stage. Mining equipment, buildings, and other fixed assets are stated at cost and depreciated on a straight-line basis over estimated useful lives ranging from one to 25 years. Leasehold improvements are amortized using the straight-line method, over the shorter of the estimated useful lives or term of the lease. Major repairs and betterments that significantly extend original useful lives or improve productivity are capitalized and depreciated over the period benefited. Maintenance and repairs are expensed as incurred. When equipment is retired or disposed, the related cost and accumulated depreciation are removed from the respective accounts and any profit or loss on disposal is recognized in Other (income) expense in the Company’s Consolidated Statements of Operations. Refer to Note 8 for further information.

Owned and leased mineral rights, net of accumulated depletion and amortization, for the years ended December 31, 2023 and 2022 were $451,160 and $451,062, respectively, and are reported in assets in the Company’s Consolidated Balance Sheets. These amounts include $27,473 and $20,284 of asset retirement obligation assets, net of accumulated amortization, associated with active mining operations for the years ended December 31, 2023 and 2022, respectively.

Costs to obtain owned and leased mineral rights are capitalized and amortized to operations as depletion expense using the units-of-production method. Only proven and probable reserves are included in the depletion base. Depletion expense is included in Depreciation, depletion and amortization in the accompanying Consolidated Statements of Operations and was $23,944, $23,078, and $23,541 for the years ended December 31, 2023, 2022, and 2021 respectively.

In accordance with ASC 842, the Company recognizes right of use assets and lease liabilities on the Consolidated Balance Sheets for all leases with a term longer than 12 months. Some of these leases include both lease and non-lease components which are accounted for as a single lease component as the Company has elected the practical expedient to combine these components for all leases. The discount rates used to determine the present value of the lease assets and liabilities are based on the Company’s incremental borrowing rate at the lease commencement date and commensurate with the remaining lease term. As the rates implicit in most of the Company’s leases are not readily determinable, the Company uses a collateralized incremental borrowing rate based on the information available at the lease commencement date in determining the present value of future payments. The Company uses the portfolio approach and groups leases by short-term and long-term categories, applying the corresponding incremental borrowing rates to these categories of leases. For leases with a term of 12 months or less, no right of use assets or liabilities are recognized on the Consolidated Balance Sheets and the Company recognizes the lease expense on a straight-line basis over the lease term. Additionally, the Company recognizes variable lease payments as an expense in the period incurred. The Company has elected to show net instead of gross amounts for right-of-use assets and liabilities within its Consolidated Statements of Cash Flows. Refer to Note 11 for further information.

The Company has recognized assets for acquired mine permits which were valued based on the replacement cost and lost profits method as of the Merger date. The balances of such assets as of December 31, 2023 and 2022, net of accumulated amortization, were $46,579 and $55,102, respectively, and are included within Other acquired intangibles, net of accumulated amortization, on the Company’s Consolidated Balance Sheets.

Additionally, the Company previously recognized assets for acquired above market-priced coal supply agreements and liabilities for acquired below market-priced coal supply agreements. The agreements were amortized over the actual number of tons shipped over the life of each contract. Amortization expense is included in Amortization of acquired intangibles, net in the accompanying Consolidated Statements of Operations and was $0, $0, and ($327) for the years ended December 31, 2023, 2022, and 2021, respectively.

Goodwill represents the excess of the purchase price over the fair value of the net identifiable tangible and intangible assets of acquired companies. Goodwill for the years ended December 31, 2023 and 2022 was $11,124 and $10,736, respectively, and is included within Other non-current assets on the Company’s Consolidated Balance Sheets. In January 2023, primarily to secure additional coal trucks and related equipment and facilities, the Company purchased substantially all the assets of a freight, hauling and transportation services business for $11,919, resulting in $388 of goodwill. The acquired goodwill, related primarily to the acquired workforce and expected cost synergies, was allocated to the Company's Met reportable segment. In December 2022, the Company purchased substantially all of the assets of a mining equipment component manufacturing and rebuild business to help secure the supply of certain underground mining equipment parts needed for the Company’s operations for $24,878, which included $7,787 of working capital, $6,355 of property, plant, and equipment, and $10,736 of goodwill. The acquired goodwill, related primarily to the acquired workforce and expected cost synergies, was allocated to the Company’s Met reportable segment. Goodwill is not amortized; instead, it is tested for impairment annually as of October 31 of each year or more frequently if indicators of impairment exist.

The Company assesses goodwill for impairment on a qualitative basis. If the Company determines that more likely than not the fair value of a reporting unit containing goodwill exceeds its carrying amount, no further impairment testing is required. If the qualitative assessment indicates that an impairment potentially exists, then the Company quantitatively tests goodwill for impairment by comparing the fair value of the reporting unit to its carrying amount. If the fair value of the reporting unit is lower than its carrying amount, its goodwill is written down by the lesser of the amount by which the reporting units carrying amount exceeded its fair value or its carrying amount of goodwill.

Long-lived assets, such as property, plant, and equipment, mineral rights, and acquired intangibles subject to amortization, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset or asset groups may not be recoverable. Recoverability of assets or asset groups to be held and used is measured by a comparison of the carrying amount of an asset or asset group to the estimated undiscounted future cash flows expected to be generated by the asset or asset group. Long-lived assets located in a close geographic area are grouped together for purposes of impairment testing when, after considering revenue and cost interdependencies, circumstances indicate the assets are used together to produce future cash flows. The Company’s asset groups generally consist of the assets and applicable liabilities of one or more mines and preparation plants and associated coal reserves for which cash flows are largely independent of cash flows of other mines, preparation plants, and associated coal reserves. If the carrying amount of an asset or asset group exceeds its estimated future cash flows, the potential impairment is equal to the amount by which the carrying amount of the asset or asset group exceeds the fair value of the asset or asset group. The Company estimates the fair value of an asset group generally using discounted cash flow analysis based on estimates of future sales volumes, coal prices, production costs, and a risk-adjusted cost of capital. These estimates generally constitute unobservable Level 3 inputs under the fair value hierarchy. The amount of impairment, if any, is allocated to the long-lived assets on a pro-rata basis, except that the carrying value of the individual long-lived assets are not reduced below their estimated fair value.

Minimum standards for mine reclamation have been established by various regulatory agencies and dictate the reclamation requirements at the Company’s operations. The Company’s asset retirement obligations consist principally of costs to reclaim acreage disturbed at surface operations and estimated costs to reclaim support acreage, treat mine water discharge, and perform other related functions at underground mines. The Company records these reclamation obligations at fair value in the period in which the legal obligation associated with the retirement of the long-lived asset is incurred. Changes to the liability at operations that are not currently being reclaimed are offset by increasing or decreasing the carrying amount of the related long-lived asset. Changes to the liability at operations that are currently being reclaimed are recorded to Depreciation, depletion, and amortization. Over time, the liability is accreted and any capitalized cost is depreciated or depleted over the useful life of the related asset. To settle the liability, the obligation is paid, and any difference between the liability and the amount of cash paid is recorded within Depreciation, depletion and amortization within the Consolidated Statements of Operations at the time the reclamation work is completed. On at least an annual basis, the Company reviews its estimated future cash flows for its asset retirement obligations. Refer to Note 15 for further information.

The Company recognizes deferred tax assets and liabilities using enacted tax rates for the effect of temporary differences between the book and tax bases of recorded assets and liabilities. Deferred tax assets are reduced by a valuation allowance if it is more likely than not that some portion or all of the deferred tax assets will not be realized. In evaluating its ability to recover deferred tax assets within the jurisdiction in which they arise, the Company considers all available positive and negative evidence, including the expected reversals of deferred tax liabilities, projected future taxable income, taxable income available via carryback to prior years, tax planning strategies, and results of recent operations. The Company assesses the realizability of its deferred tax assets, including scheduling the reversal of its deferred tax assets and liabilities, to determine the amount of valuation allowance needed. Scheduling the reversal of deferred tax asset and liability balances requires judgment and estimation. The Company believes the deferred tax liabilities relied upon as future taxable income in its assessment will reverse in the same period and jurisdiction and are of the same character as the temporary differences giving rise to the deferred tax assets that will be realized. Refer to Note 17 for further information.

The costs to obtain new debt financing or amend existing financing agreements are generally deferred and amortized to interest expense over the life of the related indebtedness or credit facility using the effective interest method. Unamortized deferred financing costs are presented in the Consolidated Balance Sheets as a direct deduction from the carrying amount of the debt liability, consistent with debt discounts or premiums. Unamortized deferred financing costs associated with undrawn credit facilities are included in the Consolidated Balance Sheets within Other non-current assets.

In accordance with ASC 606 Revenue from Contracts with Customers (“ASC 606”), the Company measures revenue based on the consideration specified in a contract with a customer and recognizes revenue as a result of satisfying its promise to transfer goods or services in a contract with a customer using the following general revenue recognition five-step model: (1) identify the contract; (2) identify performance obligations; (3) determine transaction price; (4) allocate transaction price; and (5) recognize revenue. Freight and handling costs paid to third-party carriers and invoiced to coal customers are recorded as freight and handling costs and freight and handling fulfillment revenues within cost of coal sales and coal revenues, respectively. Refer to Note 3 for further information.

As of December 31, 2023, the Company’s subsidiaries generally utilize high-deductible insurance programs for workers’ compensation claims at its operations with the exception of certain subsidiaries in which the Company is a qualified self-insurer for workers’ compensation obligations. The liabilities for workers’ compensation claims are estimates of the ultimate losses incurred based on the Company’s experience and include a provision for incurred but not reported losses. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These short-term and long-term obligations are included in the Consolidated Balance Sheets within

Accrued expenses and other current liabilities and Workers’ compensation and black lung obligations, respectively, with the related expected insurance receivables within Prepaid expenses and other current assets and Other non-current assets. As of December 31, 2023 and 2022, the workers’ compensation liability was net of a discount of $22,205 and $22,824, respectively, related to fair value adjustments associated with acquisition accounting. Refer to Note 18 for further information.

The Company is required by federal and state statutes to provide benefits to employees for awards related to black lung. As of December 31, 2023, certain of the Company’s subsidiaries are insured for black lung obligations by a third-party insurance provider and certain subsidiaries are self-insured for state black lung obligations. Certain other subsidiaries are self-insured for federal black lung benefits and may fund benefit payments through a Section 501(c)(21) tax-exempt trust fund. Charges are made to operations for black lung claims, as determined by an independent actuary at the present value of the actuarially computed liability for such benefits over the employee’s applicable term of service. The Company recognizes in its Consolidated Balance sheets the amount of the Company’s unfunded Accumulated Benefit Obligation (“ABO”) at the end of the year. The actuarial gains and losses recognized in accumulated other comprehensive income (loss) are amortized into components of net periodic benefit cost over the expected lifetime of active participants (the Company does not use a corridor method). These short-term and long-term obligations are included in the Consolidated Balance Sheets within Accrued expenses and other current liabilities and Workers’ compensation and black lung obligations, respectively. Refer to Note 18 for further information.

The Company is required to recognize the overfunded or underfunded status of a defined benefit pension plan as an asset or liability in its Consolidated Balance Sheets and to recognize changes in that funded status in the year in which the changes occur through other comprehensive (loss) income. The actuarial gains and losses recognized in accumulated other comprehensive income (loss) are amortized into components of net periodic benefit cost over the average future lifetime of participants expected to have benefits (the Company does not use a corridor method). The Company is required to measure plan assets and benefit obligations as of the date of the Company’s fiscal year-end Consolidated Balance Sheet and provide the required disclosures as of the end of each fiscal year. Refer to Note 18 for information.

As part of the Alpha Natural Resources, Inc. bankruptcy reorganization plan and the Retiree Committee Settlement Agreement, the Company assumed the liability for life insurance benefits for certain disabled and non-union retired employees. Provisions are made for estimated benefits based on annual evaluations prepared by independent actuaries. Adjustments to the probable ultimate liabilities are made annually based on an actuarial study and adjustments to the liability are recorded based on the results of this study. These obligations are included in the Consolidated Balance Sheets as Accrued expenses and other current liabilities and Other non-current liabilities. Refer to Note 18 for further information.

Basic net income per share is computed by dividing net income by the weighted-average number of outstanding common shares for the period. Diluted earnings per share reflects the potential dilution that could occur if instruments that may require the issuance of common shares in the future were settled and the underlying common shares were issued. Diluted earnings per share is computed by increasing the weighted-average number of outstanding common shares computed in basic earnings per share to include the additional common shares that would be outstanding after issuance and adjusting net income for changes that would result from the issuance. Only those securities that are dilutive are included in the calculation. In periods of loss, the number of shares used to calculate diluted earnings is the same as basic earnings per share. Refer to Note 5 for further information.

The Company recognizes expense for stock-based compensation awards based on their grant-date fair value. The expense is recorded over the respective service period of the underlying award. Liability classified stock-based compensation awards are remeasured each reporting period at fair value until the award is settled. The Company recognizes forfeitures of stock-based compensation awards as they occur. Refer to Note 19 for further information.

On July 26, 2016 (the “Initial Issue Date”), the Company issued warrants, which were classified as equity instruments, and were exercisable for cash or on a cashless basis at any time from the Initial Issue Date until July 26, 2023, and no fractional shares were issued upon warrant exercises. The exercise price and the warrant share number were adjusted in respect of certain dilutive events with respect to common stock. At 5:00 pm Eastern time on July 26, 2023 the Company’s Series A Warrants expired pursuant to their terms. Refer to Note 7 for additional information.

Investments and membership interests in joint ventures are accounted for under the equity method of accounting if the Company has the ability to exercise significant influence, but not control, over the entity. Under the equity method of accounting, the Company’s proportionate share of the entity’s comprehensive income or loss each reporting period is reflected in Equity loss in affiliates in the Consolidated Statements of Operations. Equity method investments are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the investment may not be recoverable. The carrying values of the Company’s equity method investments are included within Other non-current assets on the Company’s Consolidated Balance Sheets. Refer to Notes 9 and 10 for additional information.

Segment Disclosures: In November 2023, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures (“ASU 2023-07”). This update requires public entities to disclose significant segment expenses that are regularly provided to its chief operating decision maker and other segment items and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. The additional disclosures are required to be provided on a retrospective basis. The amendments are effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. The Company will provide the additional required disclosures upon adoption.

Income Tax Disclosures: In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures (“ASU 2023-09”). This update requires public business entities to disclose in their income tax rate reconciliation table additional categories of information about federal, state, and foreign income taxes and to provide additional details about the reconciling items in categories meeting a quantitative threshold. The guidance will also require entities to disclose income taxes paid, net of refunds, disaggregated by federal, state, and foreign taxes for annual periods and to disaggregate the information by jurisdiction based on a quantitative threshold. The additional disclosures are required to be provided on a prospective basis with the option to provide retrospectively. The amendments are effective for fiscal years beginning after December 15, 2024. The Company will provide the additional required disclosures upon adoption.