UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

SCHEDULE TO

(Rule 14d-100)

Amendment No. 15

TENDER OFFER STATEMENT UNDER SECTION 14(d)(1)
OR SECTION 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934

AUGUSTA RESOURCE CORPORATION

(Name of Subject Company (Issuer))

HUDBAY MINERALS INC.

(Names of Filing Persons (Offeror))

Common Shares
(Title of Class of Securities)

050912203

(CUSIP Number of Class of Securities)

HudBay Minerals Inc.

25 York Street, Suite 800,

Toronto, ON M5J 2V5

Attention: Patrick Donnelley, Esq.

Vice President, Legal and Corporate Secretary

(416) 362-2576(Name, address and telephone number of person authorized to receive notices and communications on behalf of filing persons)

with copies to:

	Kari MacKay, Esq.
Mark L. Mandel, Esq.	Goodmans LLP
Milbank, Tweed, Hadley & McCloy LLP	Bay Adelaide Centre
One Chase Manhattan Plaza	333 Bay Street, Suite 3400
New York, NY 10005-1413	Toronto, ON M5H 2S7
(212) 530-5026	(416) 979-2211

(Name, address and telephone number of person authorized to receive notices and communications on behalf of filing persons)

CALCULATION OF FILING FEE:

Transaction Valuation*	Amount of Filing Fee**
$238,887,478.07	$30,768.71

*Estimated solely for the purpose of calculating the amount of the filing fee based on a transaction value equal to the product of (i) US$1.795, which is the average of high and low sale prices of the common shares of Augusta Resource Corporation as reported on the NYSE MKT on February 5, 2014, and (ii) 133,084,946 Common Shares in the aggregate that may be received by Hudbay Minerals Inc. or cancelled in the transaction described herein.

**The amount of filing fee is calculated in accordance with Rule 0-11 of the Securities Exchange Act of 1934, as amended.

xCheck the box if any part of the fee is offset as provided by Rule 0-11(a)(2) and identify the filing with which the offsetting fee was previously paid.  Identify the previous filing by registration statement number or the Form or Schedule and the date of its filing.

Amount Previously Paid:	$30,768.71
Form or Registration No:	Form F-10
Filing Party:	HudBay Minerals Inc.
Date Filed:	February 11, 2014

oCheck the box if the filing relates to preliminary communications made before the commencement of a tender offer.

Check the appropriate boxes below to designate any transactions to which the statement relates:

x   THIRD-PARTY TENDER OFFER SUBJECT TO RULE 14D-1.

o    ISSUER TENDER OFFER SUBJECT TO RULE 13E-4.

o    GOING-PRIVATE TRANSACTION SUBJECT TO RULE 13E-3.

o    AMENDMENT TO SCHEDULE 13D UNDER RULE 13D-2.

Check the following box if the filing is a final amendment reporting the results of the tender offer:  o

If applicable, check the appropriate box(es) below to designate the appropriate rule provision(s) relied upon:

o    Rule 13e-4(i) (Cross-Border Issuer Tender Offer)

o    Rule 14d-1(d) (Cross-Border Third-Party Tender Offer)

This Amendment No. 15 (this “Amendment”) to Schedule TO amends and supplements the Tender Offer Statement on Schedule TO originally filed with the Securities and Exchange Commission (the “SEC”) on February 11, 2014 (the “Schedule TO”), by HudBay Minerals Inc., a corporation organized under and governed by the laws of Canada (“Hudbay”) relating to the offer to purchase (the “Offer”) by Hudbay for all of the issued and outstanding common shares (the “Augusta Shares”) of Augusta Resource Corporation, a corporation existing under the laws of Canada (“Augusta”), other than any Augusta Shares held directly or indirectly by Hudbay and its affiliates, including any Augusta Shares that may become issued and outstanding upon the exercise, exchange or conversion of any options or any other rights to acquire Augusta Shares after the date of the Offer but prior to the expiry time of the Offer, together with the associated rights issued under Augusta’s shareholder rights plan, for consideration per Augusta Share of 0.315 of a common share of Hudbay.

Hudbay has also filed a registration statement on Form F-10 with the SEC relating to the common shares it proposes to issue to Augusta shareholders in connection with the Offer that includes the Offer and Circular as a prospectus, and also has filed all other tender offer documents required under applicable Canadian and United States securities regulations.

The information set forth in the Offer and Circular (as previously amended, the “Original Offer and Circular”), the Letter of Transmittal and the Notice of Guaranteed Delivery, each as previously amended, filed, respectively, as Exhibits (a)(1)(i), (a)(1)(ii) and (a)(1)(iii) to the Schedule TO, including all schedules, exhibits and annexes thereto, is hereby expressly incorporated herein by reference in response to all items of information required to be included in, or covered by, this Schedule TO, and is supplemented by the information specifically provided herein.

ITEM 10. FINANCIAL STATEMENTS.

The first sentence of the first paragraph under the heading “Summary of the Offeror’s Historical and Pro Forma Financial Information” on page 36 of the Original Offer and Circular is hereby deleted and replaced by the following:

“Augusta Shareholders should refer to Schedule “B” to this Offer and Circular for the Offeror’s unaudited pro forma consolidated financial statements of the Offeror as at and for the year ended December 31, 2013, giving effect to the proposed acquisition of all of the issued and outstanding Augusta Shares in the manner set forth therein.”

The second paragraph under the heading “Summary of the Offeror’s Historical and Pro Forma Financial Information” on page 36 of the Original Offer and Circular is hereby deleted and replaced by the following:

“The tables set out below include a summary of (i) the Offeror’s historical consolidated financial information as at and for the years ended December 31, 2013 and 2012, prepared in accordance with IFRS, and (ii) the unaudited pro forma condensed consolidated financial information for the Offeror as at and for the year ended December 31, 2013. The historical financial information as at and for the years ended December 31, 2013 and 2012 has been derived from the Offeror’s consolidated financial statements, which are incorporated by reference herein.  The unaudited pro forma consolidated financial information for the Offeror has been derived from the audited consolidated financial statements of the Offeror and Augusta for the year ended December 31, 2013.”

The second sentence of the third paragraph under the heading “Summary of the Offeror’s Historical and Pro Forma Financial Information” on page 36 of the Original Offer and Circular is hereby deleted and replaced by the following:

“The summary unaudited pro forma consolidated financial information for the Offeror gives effect to the proposed acquisition of Augusta as if it had occurred as at December 31, 2013, for the purposes of the pro forma consolidated balance sheet information and as at January 1, 2013 for the purposes of the pro forma consolidated statement of earnings for the year ended December 31, 2013.”

That certain table “Summary of Historical Financial Information of the Offeror” on page 37 of the Original Offer and Circular is hereby deleted and replaced by the following:

Summary of Historical Financial Information of the Offeror
(in millions of $ except per share information)

	Year ended December 31
	2013		2012(2)
Certain Income Statement Data
Revenue	516.8		702.6
Gross Profit	80.0		193.9
Results from operating activities	(6.9	)	101.7
(Loss) profit from continuing operations	(109.3	)	(23.5	)
Loss from discontinued operations, net of taxes	—		—
Loss for the period/year	(109.3	)	(23.5	)
Loss per share (basic and diluted)(1)	(0.59	)	(0.12	)
Ratio of earnings to fixed charges	(0.8	)	(3.6	)

	Year ended December 31
	2013	2012
Certain Balance Sheet Data
Cash and cash equivalents	631.4	1,337.1
Property, plant and equipment	2,665.1	1,732.2
Current assets	925.2	1,527.7
Non-current assets	2,918.8	1,948.8
Total assets	3,844.0	3,476.5
Current liabilities	342.0	345.7
Long-term debt	779.3	479.5
Equity	1,627.7	1,653.5
Total liabilities and equity	3,844.0	3,476.5
Book value per share	9.5	9.6

(1)Attributable to owners.

(2)The 2012 balances reflect adjustments related to the adoption of amended IAS 19, Employee Benefits, effective January 1, 2013. As a result of the amended standards, equity was decreased by $107.5 million as at December 31, 2012. In addition, net loss was increased by $2.3 million reflecting increased employee benefit expense.

That certain table “Summary of Unaudited Pro Forma Consolidated Financial Information of the Offeror” on page 38 of the Original Offer and Circular is hereby deleted and replaced by the following:

Summary of Unaudited Pro Forma Consolidated Financial Information of the Offeror

(in millions of $ except per share information)

	Year ended		Year ended		Year ended
	Dec-31		Dec-31		Dec-31
	2013		2013		2013
	100%		33%		51%
Certain Income Statement Data
Revenue	516.8		516.8		516.8
Gross Profit	80.0		80.0		80.0
Results from operating activities	(15.1	)	(6.9	)	(15.1	)
(Loss) profit for the period/year	(107.6	)	(103.2	)	(107.6	)
(Loss) profit attributable to owners of the Company	(99.6	)	(95.3	)	(96.4	)
(Loss) profit per share (basic and diluted)(1)	(0.47	)	(0.53	)	(0.51	)
Ratio of earnings to fixed charges	(0.7	)	(0.7	)	(0.7	)
Certain Balance Sheet Data
Cash and cash equivalents	620.7		618.4		620.7
Property, plant and equipment	3,342.6		2,665.1		3,352.1
Current assets	939.7		912.2		939.7
Non-current assets	3,565.2		3,027.2		3,574.7
Total assets	4,504.9		3,939.4		4,514.4
Current liabilities	449.4		342.0		449.4
Long-term debt	786.0		779.3		786.0
Equity	2,022.3		1,723.1		2,028.1
Total liabilities and equity	4,504.9		3,939.4		4,514.4
Book value per share	9.5		9.6		10.7

(1)Attributable to owners.

The paragraph under the heading “Consolidated Capitalization” on page 39 of the Original Offer and Circular is hereby deleted and replaced by the following:

“As at the date hereof, there have been no material changes in the Hudbay Share or loan capitalization of the Offeror since December 31, 2013, other than: (i) the issuance of 20,930,000 Hudbay Shares pursuant to an equity offering (the “Equity Offering”) and (ii) the draw down of approximately $56.5 million pursuant to the equipment financing facility the Offeror has entered into with Cat Financial (the “Equipment Financing Loan”). The following table sets forth the consolidated capitalization of the Company: (i) as at December 31, 2013; (ii) as at December 31, 2013 after giving effect to the Equity Offering and the Equipment Financing Loan and before giving effect to the Offer; (iii) as at December 31, 2013 after giving effect to the Equity Offering, the Equipment Financing Loan and the acquisition in the Offer of all of the issued and outstanding Augusta Shares; (iv) as at December 31, 2013 after giving effect to the Equity Offering, the Equipment Financing Loan and the acquisition in the Offer of 33% of the issued and outstanding Augusta Shares (including Augusta Shares held by the Offeror and its affiliates prior to the commencement of the Offer); and (v) as at December 31, 2013 after giving effect to the Equity Offering, the Equipment Financing Loan and the acquisition in the Offer of 51% of the issued and outstanding Augusta Shares (including Augusta Shares held by the Offeror and its affiliates prior to the commencement of the Offer).”

That certain table “Consolidated Capitalization” on page 39 of the Original Offer and Circular is hereby deleted and replaced by the following:

	ActualDecember 31, 2013		After giving effect to the Equity Offering and the Equipment Financing Loan before giving effect to the Offer			After giving effect to the Equity Offering, the Equipment Financing Loan and the Offer(6)100%			After giving effect to the Equity Offering, the Equipment Financing Loan and the Offer(7)33%			After giving effect to the Equity Offering, the Equipment Financing Loan and the Offer(8)51%
	(Dollar amount in thousands)
Cash and cash equivalents(1)	$	631,427	$	797,031	(4)	$	786,308	(4)	$	784,031	(4)	$	786,308	(4)
Debt (including current maturities):
Existing Credit Facilities(2)	—		—			—			—			—
Other secured debt(3)	—		$	60,083		$	60,083		$	60,083		$	60,083
Total secured debt	—		$	60,083		$	60,083		$	60,083		$	60,083
Total senior unsecured debt	$	779,331	$	779,331		$	779,331		$	779,331		$	779,331
Long-term debt incurred in Offer (including current portion)(5)	—		—			$	106,146		—			$	106,146
Total debt	$	779,331	$	839,414		$	945,560		$	839,414		$	945,560
Equity:
Equity	$	1,627,707	$	1,627,707		$	1,627,707		$	1,627,707		$	1,627,707
Equity Offering(4)	—		$	165,604		$	165,604		$	165,604		$	165,604
Shares issued pursuant to the Offer	—		—			$	379,800		$	74,257		$	160,242
Total equity	$	1,627,707	$	1,793,311		$	2,173,111		$	1,867,568		$	1,953,553
Total capitalization(1)	$	2,407,038	$	2,632,725		$	3,118,671		$	2,706,982		$	2,899,113

(1)Reflects the United States dollar/Canadian dollar closing exchange rate as reported by the Bank of Canada as at December 31, 2013.

(2)As of December 31, 2013, there were no borrowings outstanding under the Credit Facility. As of December 31, 2013, the Offeror had commitments available to be borrowed under its credit facility of US$73 million (based on the maximum availability, equal to the lesser of US$100 million and a borrowing base related to accounts receivable and inventory of the Manitoba business unit); however, borrowing capacity was reduced by $64.1 million of letters of credit outstanding on such date.

(3)Does not include available credit facilities, including the undrawn portion of the equipment financing facility for the Constancia mobile fleet which the Offeror has entered into with Cat Financial. The equipment financing facility will be used to finance the purchase of up to approximately US$130 million of equipment.

(4)Reflects net proceeds from the Equity Offering of $165.6 million.

(5)On December 16, 2013, Augusta announced that it had closed an additional loan facility for US$26.6 million (the “Expanded Loan”) and had drawn down the first tranche of US$3.5 million. In connection with the Expanded Loan, Augusta paid an arrangement fee of US$1,120,000 and issued a total of 3.3 million Warrants to the lender with an exercise price of US$2.12 per share, subject to amendment if certain conditions are not met. The Warrants expire on December 12, 2016.

(6)Refer to the unaudited pro forma consolidated financial statements of the Offeror for the year ended December 31, 2013 attached as Schedule “B” to this Offer and Circular for details regarding the assumptions used to calculate the effect of the Offer.

(7)Refer to the unaudited pro forma consolidated financial statements of the Offeror for the year ended December 31, 2013 attached as Schedule “D” to this Offer and Circular for details regarding the assumptions used to calculate the effect of the Offer.

(8)Refer to the unaudited pro forma consolidated financial statements of the Offeror for the year ended December 31, 2013 attached as Schedule “E” to this Offer and Circular for details regarding the assumptions used to calculate the effect of the Offer.

Schedules “B”, “D” and “E” to the Original Offer and Circular are hereby deleted and replaced with the following:

SCHEDULE B

UNAUDITED PRO FORMA FINANCIAL STATEMENT

Hudbay Minerals Inc.

Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

Hudbay Minerals Inc.

Pro Forma Consolidated Balance Sheet

(Unaudited) As at December 31, 2013

(expressed in thousands of Canadian dollars)

	Hudbay$		Augusta$		Adjustments$		Note 4	Pro formaconsolidated$
			(note 1)
Assets
Current assets
Cash and cash equivalents	631,427		2,412		(13,135	)	(b),(c),(f)	620,704
Trade and other receivables	168,298		8,156		—			176,454
Inventories	52,201		—		—			52,201
Prepaid expenses and other current assets	28,917		16,957		—			45,874
Other financial assets - current	807		146		—			953
Taxes receivable	37,644		—		—			37,644
Assets held for sale	5,864		—		—			5,864
Total current assets	925,158		27,671		(13,135	)		939,694
Receivables	57,376		—		—			57,376
Inventories	7,888		—		—			7,888
Prepaid expenses	574		—		—			574
Other financial assets - long-term	71,182		1,449		(34,126	)	(g),(h)	38,505
Intangible assets - computer software	13,573		1,485		—			15,058
Property, plant, and equipment	2,665,075		311,855		365,681		(d)	3,342,611
Goodwill	71,373		—		—			71,373
Deferred tax assets	31,787		—		—			31,787
Total assets	3,843,986		342,460		318,420			4,504,866
Liabilities
Current liabilities
Trade and other payables	218,898		4,707		—			223,605
Taxes payable	33		—		—			33
Other liabilities	41,139		3,194		—			44,333
Other financial liabilities - current	16,348		99,464		—			115,812
Deferred revenue	65,616		—		—			65,616
Total current liabilities	342,034		107,365		—			449,399
Other financial liabilities	23,039		3,848		—			26,887
Long-term debt	779,331		6,682		—		(e)	786,013
Deferred revenue	464,135		—		—			464,135
Provisions	146,062		—		—			146,062
Pension obligations	25,931		—		—			25,931
Other employee benefits	142,114		—		—			142,114
Deferred tax liabilities	293,633		3,583		144,810		(d)	442,026
Total liabilities	2,216,279		121,478		144,810			2,482,567
Shareholders’ Equity
Share capital (note 5)	1,021,088		235,031		144,769		(a),(c),(f),(i)	1,400,888
Reserves	49,557		28,734		(28,873	)	(a),(g),(h),(i)	49,418
Retained earnings	564,966		(42,783	)	57,714		(a),(b),(h)	579,897
Total equity attributable to Hudbay shareholders	1,635,611		220,982		173,610			2,030,203
Non-controlling interest	(7,904	)	—		—			(7,904	)
Total equity	1,627,707		220,982		173,610			2,022,299
Total liabilities and shareholders’ equity	3,843,986		342,460		318,420			4,504,866

The accompanying notes are an integral part of these pro forma consolidated financial statements.

Hudbay Minerals Inc.

Pro Forma Consolidated Statement of Income

(Unaudited) For the year ended December 31, 2013

(expressed in thousands of Canadian dollars)

	Hudbay$		Augusta$		Adjustments$		Note 4	Pro formaconsolidated$
			(note 1)
Revenue	516,801		—		—			516,801
Cost of sales
Mine operating costs	360,085		—		—			360,085
Depreciation and amortization	76,714				—			76,714
	436,799		—		—			436,799
Gross profit	80,002		—		—			80,002
Selling and administrative expenses	39,956		6,737		—			46,693
Exploration and evaluation	23,286		1,493		—			24,779
Other operating income	(913	)	—		—			(913	)
Other operating expenses	9,197		—		—			9,197
Asset impairment loss	15,356		—		—			15,356
Results from operating activities	(6,880	)	(8,230	)	—			(15,110	)
Finance income	(3,494	)	(811	)	—			(4,305	)
Finance expenses	8,921		249		—			9,170
Other finance losses	43,697		(826	)	(8,414	)	(h),(i)	34,457
Net finance expense	49,124		(1,388	)	(8,414	)		39,322
Loss before tax	(56,004	)	(6,842	)	8,414			(54,432	)
Tax expense	53,272		(151	)	—			53,121
Loss for the year	(109,276	)	(6,691	)	8,414			(107,553	)
Attributable to
Owners of the Company	(101,359	)						(99,636	)
Non-controlling interests	(7,917	)						(7,917	)
Loss for the year	(109,276	)						(107,553	)
Loss per share attributable to owners of the Company
Basic and diluted (note 6)	(0.59	)						(0.47	)
Weighted average number of common shares outstanding
Basic and diluted (in thousands) (note 6)	172,048							212,452

The accompanying notes are an integral part of these pro forma consolidated financial statements.

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

1Basis of presentation

The unaudited pro forma consolidated balance sheet of Hudbay Minerals Inc. (the “Company” or “Hudbay”) as at December 31, 2013 and the unaudited pro forma consolidated statement of income for the year ended December 31, 2013 have been derived by management based on financial statements prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board (IASB), for illustrative purposes only, after giving effect to the proposed acquisition of Augusta Resource Corporation (“Augusta”) by the Company. Adjustments applied are directly attributable to the transaction, factually supportable, and expected to have a continuing impact. Terms not otherwise defined herein have the meanings given thereto in the Company’s offer and take-over bid circular dated February 10, 2014, as amended.

These unaudited pro forma consolidated financial statements have been compiled as follows:

a)an unaudited pro forma consolidated balance sheet giving effect to the transaction described in note 3, as if the transaction occurred on December 31, 2013 combining:

·the audited consolidated balance sheet of the Company as at December 31, 2013; and

·the audited consolidated statement of financial position of Augusta as at December 31, 2013.

b)an unaudited pro forma consolidated income statement for the year ended December 31, 2013, which assumes the transaction occurred as of January 1, 2013, combining:

·the audited consolidated income statement of the Company for the year ended December 31, 2013; and

·the audited consolidated statement of comprehensive loss of Augusta for the year ended December 31, 2013.

It is management’s opinion that these unaudited pro forma consolidated financial statements include all adjustments necessary for the fair presentation, in all material respects, of the transactions described in notes 3 and 4 in accordance with IFRS, applied on a basis consistent with the Company’s accounting policies. The unaudited pro forma consolidated financial information is not necessarily indicative of the results of operations that might be obtained in the future.

The unaudited pro forma consolidated financial statements should be read in conjunction with the historical consolidated financial statements and notes thereto of the Company and Augusta.

1

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

Augusta’s financial statements are presented in United States dollars. For the purposes of these unaudited pro forma consolidated financial statements, line items have been translated into Canadian dollars at the following rates:

·December 31, 2013 balance sheet at the exchange rate of $1.0636; and

·December 31, 2013 income statement at the average rate for the year of $1.0299.

All foreign exchange rates have been obtained from the Bank of Canada website. Unless where otherwise noted, these unaudited pro forma consolidated financial statements and their accompanying notes are presented in Canadian dollars.

Prior to the transaction described in note 3, the Company owned 23,058,585 shares of Augusta, which were recorded on the audited consolidated year-end balance sheet of the Company as at December 31, 2013 at a fair value of $34,127 (cost of $69,058).

The allocation of the preliminary purchase price to reflect the fair values of the assets acquired and liabilities assumed is based on management’s estimate of such assets and liabilities and, accordingly, the adjustments that have been included in the pro forma consolidated balance sheet may be subject to change. For purposes of these pro forma financial statements, the excess of the purchase price over the estimated fair value of the net assets acquired has been allocated to property, plant and equipment. The final purchase price allocations may differ materially from the allocations included herein.

2Summary of significant accounting policies

These unaudited pro forma consolidated financial statements have been compiled using the significant accounting policies, as set out in the audited consolidated financial statements of the Company as at December 31, 2013. Management has determined, based on their initial assessment, that certain adjustments are necessary to conform Augusta’s audited consolidated financial statements to the accounting policies used by the Company in the preparation of its audited consolidated financial statements:

a)Stock based compensation - Augusta capitalizes stock based compensation related to personnel that service their development project to development costs. Hudbay expenses similar charges to various income statement accounts. The amount of the cumulative impact is unknown at the current time.

b)Deposits and prepayments on long-lead equipment - Augusta presents this as a separate financial statement line item. Hudbay groups these assets within prepaid expenses. An amount of $12,413 has been reclassified to conform to Hudbay policies.

2

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

3The transaction

Proposed transaction

Hudbay has offered to purchase all of the issued and outstanding common shares of Augusta, other than any Augusta Shares held directly or indirectly by Hudbay and its affiliates, including any Augusta Shares that may become issued and outstanding after the date hereof but before the expiry time upon the exercise, exchange or conversion of any convertible securities, together with the associated rights issued under the Shareholder Rights Plan.

The transaction will be accounted for as a business combination with Hudbay identified as the acquirer. A summary of the allocation of the preliminary purchase price to the acquired assets and liabilities assumed is as follows:

	$
Preliminary purchase price
Hudbay share consideration (note 4(a(ii)))	379,800
Fair value of Augusta options settled in cash (note 4(f))	5,345
Fair value of Augusta warrants exchanged for Hudbay warrants (note 4(i))	642
Fair value of Augusta shares previously held by Hudbay (note 4(g))	68,276
Total consideration	454,063

3

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

The preliminary purchase price has been allocated to the following net assets based on their estimated fair values as of December 31, 2013:

	$	Pro formapresentation$
Assets acquired and liabilities assumed Cash and cash equivalents (note 4(c),(f))		14,622
Accounts receivable	8,141
Due from related parties	15
Trade and other receivables		8,156
Prepaids and other	4,544
Deposits on long-lead equipment	12,413
Prepaid expenses and other current assets		16,957
Short-term investments	146
Other financial assets - current		146
Restricted funds	410
Other assets	1,039
Other financial assets		1,449
Other assets	1,485
Intangible assets - computer software		1,485
Development costs	193,812
Property, plant, and equipment	91,887
Mineral properties	26,156
Property, plant and equipment		311,855
Current liabilities		(107,365	)
Long-term liabilities		(10,530	)
Deferred tax liabilities		(148,393	)
Unallocated purchase price (note 1)		365,681
Total net assets acquired		454,063

The final purchase price and the fair value of the net assets of Augusta to be acquired will ultimately be determined after the closing of the transaction. Therefore, it is likely that the purchase price, including share consideration, and the fair values of assets acquired and liabilities assumed will vary from those shown above. These differences may be material. For purposes of sensitivity, a 10% increase in Hudbay share price is estimated to increase the purchase price by approximately $45,000.

4

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

4Pro forma assumptions and adjustments

The unaudited pro forma consolidated financial statements reflect the following assumptions and adjustments to give effect to the acquisition of all of the issued and outstanding common shares of Augusta as described in note 3 as if the transactions had occurred on January 1, 2013 for statement of income items and December 31, 2013 for balance sheet items. Assumptions relating to the share price of Hudbay or Augusta have used the date of February 7, 2014 which represents the last trading day before February 10, 2014.

a)i)An adjustment to eliminate the historical equity accounts of Augusta.

ii)An adjustment to reflect the issuance of 40,404,237 Hudbay shares in exchange for 128,267,418 common shares of Augusta representing a share exchange ratio of 0.315 Hudbay share to 1 Augusta share. The closing price of Augusta shares on February 7, 2014 was $2.51. Future movements in share prices may impact the share numbers disclosed within.

b)An adjustment to reflect the transaction costs related to the transaction, including $7,000 of change of control payments and $13,000 in professional fees.

c)For purposes of pro forma presentation, no adjustment has been made to settle or convert the existing debt on Augusta’s statement of financial position on the assumption that this debt is out-of the money as at February 7, 2014.

On December 16, 2013, Augusta announced that it has closed an additional loan facility for US$26.6 million (the “Expanded Loan”) and has drawn down the first tranche of US$3.5 million. In connection with the Expanded Loan, Augusta paid an arrangement fee of US$1.12 million and issued a total of 3.3 million common share purchase warrants (“Warrants”) to the lender with an exercise price of US$2.12 per share, subject to amendment if certain conditions are not met. The Warrants expire on December 12, 2016.

An adjustment has been reflected for the impact of the exercise of these warrants upon change of control. The impact on the share consideration of the exercise of these warrants is an increase of $6,996 and the issuance of an additional 1,039,500 Hudbay common shares.

d)An adjustment to reflect the fair value of the property, plant, and equipment acquired, in excess of the book value and the resulting deferred tax liability, assuming an income tax rate of 39.6%. The applicable tax rate is based on the tax jurisdiction of the asset where it will be recovered through use.

e)On September 4, 2013, Augusta closed the first tranche for $2,000 of a previously announced financing for a total of $10,000 in convertible unsecured notes. The second tranche of $1,500 closed on September 19, 2013. The third tranche is assumed to have closed on October 25, 2013. The fourth tranche closed on October 25, 2013. Together, the third and fourth tranche totalled $3,250.

This disclosure is provided for informational purposes only.

5

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

f)An adjustment to reflect the cash paid for the fair value of stock options issued by Augusta of $5,345, outstanding as at February 7, 2014 which are estimated to be out of-the-money. The options have been valued using a Black-Scholes model, using the share price of Augusta as at February 7, 2014, and the following assumptions: exercise prices ($2.78 to $4.35), life of options (3.13 to 3.54 years), interest rate (1.13%) and volatility rates (90.8% to 92.2%).

All other options that are estimated to be in-the-money as February 7, 2014, are assumed to be converted into common shares of Augusta, with the corresponding exercise price received as proceeds of $5,214.

g)An adjustment to re-measure the fair value of the Company’s existing investment in Augusta held prior to acquisition of control. This investment is designated as an available-for-sale investment by Hudbay, carried at fair value and all fair value changes are recognized in other comprehensive income (OCI), except for other than temporary decline in values recognized in the statement of comprehensive loss.

h)An adjustment to eliminate the Company’s existing investment in Augusta as at December 31, 2013 and an adjustment to eliminate the related accumulated fair value gains (losses) in reserves. Correspondingly, recognized fair value changes in the statement of income are eliminated of $8,314 for the year ended December 31, 2013.

i)An adjustment to reflect the warrants issued by Hudbay in exchange for the warrants issued by Augusta, outstanding as at February 7, 2014. For purposes of pro forma presentation, the warrants issued by Augusta are assumed to be out-of-the money (except for those noted in 4(c)) and therefore not exercised. Based on the exchange share ratio of Hudbay shares for Augusta shares (note 4(a)) of 0.315 to 1, respectively, 564,386 warrants were issued on February 7, 2014. The warrants have been valued using a Black-Scholes model using the following assumptions: exercise price of $12.22, interest rates of 0.78% to 1.13%, life of warrants of 1.47 to 2.47 years and volatility rates of 40.4% to 40.7%.

An adjustment was also made to eliminate losses arising in the year ended December 31, 2013 from re-measurement of warrants issued by Augusta recognized in its statement of comprehensive income of $100.

j)All unvested restricted shares and restricted share units of Augusta are assumed to vest immediately on February 10, 2014. An adjustment is made for the issuance of the common shares of $2,058.

5Pro forma share capital

	Number ofshares(000s)	$
Hudbay’s common shares outstanding	172,078	1,021,088
Hudbay’s common shares issued under the proposed transaction (note 4(a))	40,404	379,800
Pro forma share capital	212,482	1,400,888

6

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

6Pro forma loss per share

For the purposes of the unaudited pro forma consolidated financial statements, the loss per share has been calculated using the weighted average number of shares which would have been outstanding as at the year end, after giving effect to the transaction described in notes 3 and 4 as if it had occurred on January 1, 2013.

	$
Actual weighted average number of Hudbay shares outstanding (thousands)	172,048
Assumed number of Hudbay shares issued to Augusta shareholders (note 4(a)) (thousands)	40,404
Pro forma weighted average number of Hudbay shares outstanding (thousands)	212,452
Pro forma loss attributable to owners of the Company	(99,636	)
Pro forma loss per share - basic and diluted	(0.47	)

7

SCHEDULE D

UNAUDITED PRO FORMA FINANCIAL STATEMENT

Hudbay Minerals Inc.

Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

Hudbay Minerals Inc.

Pro Forma Consolidated Balance Sheet

(Unaudited) As at December 31, 2013

(expressed in thousands of Canadian dollars)

	Hudbay$		Adjustments$		Note 4	Pro formaconsolidated$
Assets
Current assets
Cash and cash equivalents	631,427		(13,000	)	(b)	618,427
Trade and other receivables	168,298		—			168,298
Inventories	52,201		—			52,201
Prepaid expenses and other current assets	28,917		—			28,917
Other financial assets	807		—			807
Taxes receivable	37,644		—			37,644
Assets held for sale	5,864		—			5,864
Total current assets	925,158		(13,000	)		912,158
Receivables	57,376		—			57,376
Inventories	7,888		—			7,888
Prepaid expenses	574		—			574
Investment in Augusta	—		142,532		(a)	142,533
Other financial assets - long-term	71,182		(34,126	)	(d)	37,055
Intangible assets - computer software	13,573		—			13,573
Property, plant and equipment	2,665,075		—			2,665,075
Goodwill	71,373		—			71,373
Deferred tax assets	31,787		—			31,787
Total assets	3,843,986		95,406			3,939,392
Liabilities
Current liabilities
Trade and other payables	218,898		—			218,898
Taxes payable	33		—			33
Other liabilities	41,139		—			41,139
Other financial liabilities - current	16,348		—			16,348
Deferred revenue	65,616		—			65,616
Total current liabilities	342,034		—			342,034
Other financial liabilities	23,039		—			23,039
Long-term debt	779,331		—			779,331
Deferred revenue	464,135		—			464,135
Provisions	146,062		—			146,062
Pension obligations	25,931		—			25,931
Other employee benefits	142,114		—			142,114
Deferred tax liabilities	293,633		—			293,633
Total liabilities	2,216,279		—			2,216,279
Shareholders’ Equity
Share capital	1,021,088		74,256		(a)	1,095,344
Reserves	49,557		(34,931	)	(d)	14,626
Retained earnings	564,966		56,081		(b), (c)	621,047
Total equity attributable to Hudbay shareholders	1,635,611		95,406			1,731,017
Non-controlling interests	(7,904	)	—			(7,904	)
Total equity	1,627,707		95,406			1,723,113
Total liabilities and shareholders’ equity	3,843,986		95,406			1,731,017

The accompanying notes are an integral part of these pro forma consolidated financial statements.

Hudbay Minerals Inc.

Pro Forma Consolidated Statement of Income

(Unaudited) For the year ended December 31, 2013

(expressed in thousands of Canadian dollars)

	Hudbay$		Adjustments$		Note 4	Pro formaconsolidated$
Revenue	516,801		—			516,801
Cost of sales
Mining operating costs	360,085		—			360,085
Depreciation and amortization	76,714		—			76,714
	436,799		—			436,799
Gross profit	80,002		—			80,002
Selling and administrative expenses	39,956		—			39,956
Exploration and evaluation	23,286		—			23,286
Other operating income	(913	)	—			(913	)
Other operating expenses	9,197		—			9,197
Asset impairment loss	15,356		—			15,356
Results from operating activities	(6,880	)	—			(6,880	)
Finance income	(3,494	)	—			(3,494	)
Finance expenses	8,921		—			8,921
Other finance losses	43,697		(8,314	)	(d)	35,383
Net finance expense	49,124		(8,314	)		40,810
Share of investment in Augusta			(2,230	)	(e)	(2,230	)
Loss before tax	(56,004	)	6,084			(49,920	)
Tax expense	53,272		—			53,272
Loss for the year	(109,276	)	6,084			(103,192	)
Attributable to
Owners of the Company	(101,359	)	6,084			(95,275	)
Non-controlling interests	(7,917	)	—			(7,917	)
Loss for the year	(109,276	)	6,084			(103,192	)
Loss per share attributable to owners of the company
Basic and diluted (note 6)	(0.59	)				(0.53	)
Weighted average shares outstanding (thousands)
Basic and diluted (in thousands) (note 6)	172,048					179,948

The accompanying notes are an integral part of these pro forma consolidated financial statements.

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

1Basis of presentation

The unaudited pro forma consolidated balance sheet of Hudbay Minerals Inc. (the “Company” or “Hudbay”) as at December 31, 2013 and the unaudited pro forma consolidated income statement for the year ended December 31, 2013 have been derived by management based on financial statements prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board (IASB), for illustrative purposes only, after giving effect to the acquisition of a 33% interest in the share capital of Augusta Resource Corporation (“Augusta”) including common shares the Company owned prior to the Take-over Bid Circular, by the Company (note 3). Adjustments applied are directly attributable to the transaction, factually supportable, and expected to have a continuing impact. Terms not otherwise defined herein have the meanings given thereto in the Company’s offer and take0-over bid circular February 10, 2014, as amended.

These unaudited pro forma consolidated financial statements have been compiled as follows:

a)an unaudited pro forma consolidated balance sheet giving effect to the transaction described in note 3, as if the transaction occurred on December 31, 2013 based on:

·the audited consolidated balance sheet of the Company as at December 31, 2013; and

·information derived from the audited consolidated statement of financial position of Augusta as at December 31, 2013.

b)an unaudited pro forma consolidated income statement for the year ended December 31, 2013, which assumes the transaction occurred as of January 1, 2013, based on:

·the audited consolidated income statement of the Company for the year ended December 31, 2013; and

·information derived from the audited consolidated statement of comprehensive loss of Augusta for the year ended December 31, 2013.

It is management’s opinion that these unaudited pro forma consolidated financial statements include all adjustments necessary for the fair presentation, in all material respects, of the transactions described in notes 3 and 4 in accordance with IFRS, applied on a basis consistent with the Company’s accounting policies. The unaudited pro forma consolidated financial information is not necessarily indicative of the results of operations that might be obtained in the future.

1

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

The unaudited pro forma consolidated financial statements should be read in conjunction with the historical consolidated financial statements and notes thereto of the Company and Augusta.

Augusta’s financial statements are presented in United States dollars. For the purposes of these unaudited pro forma consolidated financial statements, line items have been translated into Canadian dollars at the following rates:

·December 31, 2013 balance sheet at the exchange rate of $1.0636; and

·December 31, 2013 income statement at the average rate for the year of $1.0299.

All foreign exchange rates have been obtained from the Bank of Canada website. Unless where otherwise noted, these unaudited pro forma consolidated financial statements and their accompanying notes are presented in Canadian dollars.

Prior to the transaction described in note 3, the Company owned 23,058,585 shares of Augusta which were recorded on the audited consolidated year-end balance sheet of the Company at December 31, 2013 at a fair value of $34,127 (cost of $69,058).

The Company assumes it will have significant influence over Augusta subsequent to the transaction. The allocation of the preliminary purchase price to reflect the fair values of the identifiable net assets is based on management’s estimate of such assets and liabilities and, accordingly, the adjustments that have been included in the pro forma consolidated balance sheet may be subject to change. The final purchase price allocations may differ materially from the allocations included herein.

2Summary of significant accounting policies

These unaudited pro forma consolidated financial statements have been compiled using the significant accounting policies, as set out in the audited consolidated financial statements of the Company as at December 31, 2013. Management has determined, based on their initial assessment, that certain adjustments maybe necessary to conform Augusta’s audited consolidated financial statements to the accounting policies used by the Company in the preparation of its audited consolidated financial statements:

a)Stock based compensation — Augusta capitalizes stock based compensation related to personnel that service their development project to development costs. Hudbay expenses similar charges to various income statement accounts. The amount of the cumulative impact is unknown at the current time.

2

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

3The transaction

Proposed transaction

These pro forma financial statements have been prepared on the basis consistent with the terms of the Take-over Bid Circular, but under the assumption that Hudbay acquires 33% of the issued and outstanding common shares of Augusta, including any Augusta Shares held directly or indirectly by Hudbay and its affiliates prior to the Take-over Bid Circular.

The transaction will be accounted for as an investment in associate under the equity method. A summary of the allocation of the preliminary purchase price to the acquired assets and liabilities assumed is as follows:

	$
Preliminary purchase price
Hudbay share consideration (note 4(a))	74,256
Fair value of Augusta shares previously held by Hudbay (note 4(c))	68,276
Total consideration	142,532

The final purchase price and the Company’s share of Augusta’s fair value of the identifiable net assets acquired will ultimately be determined at the closing of the transaction. For these pro forma financial statements, the Company assumes that the fair value of net assets acquired is equal to the total consideration paid. It is likely that the purchase price, including share consideration, and the fair values of net assets acquired will vary from those shown above. These differences may be material.  For purposes of sensitivity, a 10% increase in Hudbay share price is estimated to increase the purchase price by approximately $14,000.

4Pro forma assumptions and adjustments

The unaudited pro forma consolidated financial statements reflect the following assumptions and adjustments to give effect to the acquisition of 33% of the issued and outstanding common shares of Augusta as described in note 3 as if the transactions had occurred on January 1, 2013 for statement of income items and December 31, 2013 for balance sheet items. Assumptions relating to the share price of Hudbay or Augusta have used the date of February 7, 2014 which represents the last trading day before February 10, 2014.

a)An adjustment to reflect the issuance of 7,899,596 Hudbay shares in exchange for 25,078,082 common shares of Augusta representing a share exchange ratio of 0.315 Hudbay share to 1 Augusta share and an adjustment to recognize the related investment in Augusta. The closing price of Augusta shares on February 7, 2014 was $2.51. Future movements in share prices may impact the share numbers disclosed within.

b)An adjustment to reflect the transaction costs of $13,000 in professional fees.

3

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

c)An adjustment to re-measure the fair value of the Company’s existing investment in Augusta held prior to investment becoming an associate. This adjustment is recognized under the “Reserves” account in the pro forma consolidated balance sheet. The investment is designated as an available-for-sale investment by Hudbay, carried at fair value and all fair value changes are recognized in other comprehensive income (OCI), except for declines in values which are significant or prolonged which are recognized in the Company’s consolidated income statement.

d)An adjustment to eliminate the Company’s existing investment in Augusta as at December 31, 2013, previously held as an available for sale investment and an adjustment to eliminate the related accumulated fair value gains (losses) in reserves. Correspondingly, recognized fair value changes in the statement of income are eliminated of $8,314 for the year ended December 31, 2013.

e)An adjustment to recognize Hudbay’s proportionate share of Augusta’s loss for the period.

5Pro forma share capital

	Numberof shares(000s)	$
Hudbay’s common shares outstanding	172,078	1,021,088
Hudbay’s common shares issued under the proposed transaction (note 4(a))	7,900	74,256
Pro forma share capital	179,978	1,095,344

6Pro forma loss per share

For the purposes of the unaudited pro forma consolidated financial statements, the loss per share has been calculated using the weighted average number of shares which would have been outstanding as at the year end, after giving effect to the transaction described in notes 3 and 4 as if it had occurred on January 1, 2013.

	$
Actual weighted average number of Hudbay shares outstanding (thousands)	172,048
Assumed number of Hudbay shares issued to Augusta shareholders (note 4(a)) (thousands)	7,900
Pro forma weighted average number of Hudbay shares outstanding - basic (thousands)	179,948
Pro forma loss attributable to owners of the Company	(95,275	)
Pro forma loss per share — basic and diluted	(0.4453	)

4

SCHEDULE E

UNAUDITED PRO FORMA FINANCIAL STATEMENT

Hudbay Minerals Inc.

Pro Forma Consolidated Financial Statements

(Unaudited)

December 31, 2013

(expressed in thousands of Canadian dollars)

Hudbay Minerals Inc.

Pro Forma Consolidated Balance Sheet

(Unaudited) As at December 31, 2013

(expressed in thousands of Canadian dollars)

	Hudbay$		Augusta$		Adjustments$		Note 4	Pro formaconsolidated$
			(note 1)
Assets
Current assets
Cash and cash equivalents	631,427		2,412		(13,135	)	(b),(c),(f)	620,704
Trade and other receivables	168,298		8,156		—			176,454
Inventories	52,201		—		—			52,201
Prepaid expenses and other current assets	28,917		16,957		—			45,874
Other financial assets - current	807		146		—			953
Taxes receivable	37,644		—		—			37,644
Assets held for sale	5,864		—		—			5,864
Total current assets	925,158		27,671		(13,135	)		939,694
Receivables	57,376		—		—			57,376
Inventories	7,888		—		—			7,888
Prepaid expenses	574		—		—			574
Other financial assets - long-term	71,182		1,449		(34,126	)	(g),(h)	38,505
Intangible assets - computer software	13,573		1,485		—			15,058
Property, plant and equipment	2,665,075		311,855		375,205		(d)	3,352,135
Goodwill	71,373		—					71,373
Deferred tax assets	31,787		—					31,787
Total assets	3,843,986		342,460		327,944			4,514,390
Liabilities
Current liabilities
Trade and other payables	218,898		4,707		—			223,605
Taxes payable	33		—		—			33
Other liabilities	41,139		3,194		—			44,333
Other financial liabilities - current	16,348		99,464		—			115,812
Deferred revenue	65,616		—		—			65,616
Total current liabilities	342,034		107,365		—			449,399
					—
Other financial liabilities	23,039		3,848		—			26,887
Long-term debt	779,331		6,682		—		(e)	786,013
Deferred revenue	464,135		—		—			464,135
Provisions	146,062		—		—			146,062
Pension obligations	25,931		—		—			25,931
Other employee benefits	142,114		—		—			142,114
Deferred tax liabilities	293,633		3,583		148,582		(d)	445,798
Total liabilities	2,216,279		121,478		148,582			2,486,339
Shareholders’ Equity
Share capital (note 5)	1,021,088		235,031		(74,789	)	(a),(c),(f),(j)	1,181,330
Reserves	49,557		28,734		(28,873	)	(a),(i),(g),(h),(j)	49,418
Retained earnings (deficit)	564,966		(42,783	)	57,714		(a),(b),(h)	579,897
Total equity attributable to Hudbay shareholders	1,635,611		220,982		(45,948	)		1,810,645
Non-controlling interests	(7,904	)	—		225,310		(a)	217,406
Total equity	1,627,707		220,982		179,362			2,028,051
Total liabilities and shareholders’ equity	3,843,986		342,460		327,944			4,514,390

The accompanying notes are an integral part of these pro forma consolidated financial statements.

Hudbay Minerals Inc.

Pro Forma Consolidated Statement of Income

(Unaudited) For the year ended December 31, 2013

(expressed in thousands of Canadian dollars)

	Hudbay$		Augusta$		Adjustments$		Note 4	Pro formaconsolidated$
			(note 1)
Revenue	516,801		—		—			516,801
Cost of sales
Mining operating costs	360,085		—		—			360,085
Depreciation and amortization	76,714		—		—			76,714
	436,799		—		—			436,799
Gross profit	80,002		—		—			80,002
Selling and administrative expenses	39,956		6,737		—			46,693
Exploration and evaluation	23,286		1,493		—			24,779
Other operating income	(913	)	—		—			(913	)
Other operating expenses	9,197		—		—			9,197
Asset impairment loss	15,356		—		—			15,356
Results from operating activities	(6,880	)	(8,230	)	—			(15,110	)
Finance income	(3,494	)	(811	)	—			(4,305	)
Finance expenses	8,921		249		—			9,170
Other finance losses	43,697		(826	)	(8,414	)	(h) (i)	34,457
Net finance expense	49,124		(1,388	)	(8,414	)		39,322
Loss before tax	(56,004	)	(6,842	)	8,414			(54,432	)
Tax expense (recovery)	53,272		(151	)	—			53,121
Loss for the period	(109,276	)	(6,691	)	8,414			(107,553	)
Attributable to
Owners of the Company	(101,359	)	(6,691	)	11,692			(96,358	)
Non-controlling interests	(7,917	)	—		(3,278	)	(a)	(11,195	)
Loss for the period	(109,276	)	(6,691	)	8,414			(107,553	)
Loss per share attributable to owners of the company
Basic and diluted (note 6)	(0.59	)						(0.51	)
Weighted average number of common shares outstanding
Basic and diluted (in thousands) (note 6)	172,048							189,095

The accompanying notes are an integral part of these pro forma consolidated financial statements.

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

1Basis of presentation

The unaudited pro forma consolidated balance sheet of Hudbay Minerals Inc. (the “Company” or “Hudbay”) as at December 31, 2013 and the unaudited pro forma consolidated statements of income for the year ended December 31, 2013 have been derived by management based on financial statements prepared in accordance with International Financial Reporting Standards (IFRS) as issued by the International Accounting Standards Board (IASB), for illustrative purposes only, after giving effect to the acquisition of 51% of the share capital of Augusta Resource Corporation (“Augusta”) including common shares the Company owned prior to the Take-over Bid Circular, by the Company (note 3). Adjustments applied are directly attributable to the transaction, factually supportable, and expected to have a continuing impact. Terms not otherwise defined herein have the meanings given thereto in the Company’s offer and take-over bid circular dated February 10, 2014, as amended.

These unaudited pro forma consolidated financial statements have been compiled as follows:

a)an unaudited pro forma consolidated balance sheet giving effect to the transaction described in note 3, as if the transaction occurred on December 31, 2013 combining:

·the audited consolidated balance sheet of the Company as at December 31, 2013; and

·the audited consolidated statements of financial position of Augusta as at December 31, 2013.

b)an unaudited pro forma consolidated income statement for the year ended December 31, 2013, which assumes the transaction occurred as of January 1, 2013, combining:

·the audited consolidated income statement of the Company for the year ended December 31, 2013; and

·the audited consolidated statements of comprehensive loss of Augusta for the year ended December 31, 2013.

It is management’s opinion that these unaudited pro forma consolidated financial statements include all adjustments necessary for the fair presentation, in all material respects, of the transactions described in notes 3 and 4 in accordance with IFRS, applied on a basis consistent with the Company’s accounting policies. The unaudited pro forma consolidated financial information is not necessarily indicative of the results of operations that might be obtained in the future.

The unaudited pro forma consolidated financial statements should be read in conjunction with the historical consolidated financial statements and notes thereto of the Company and Augusta.

1

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

Augusta’s financial statements are presented in United States dollars. For the purposes of these unaudited pro forma consolidated financial statements, line items have been translated into Canadian dollars at the following rates:

·December 31, 2013 balance sheet at the exchange rate of $1.0636; and

·December 31, 2013 income statement at the average rate for the year of $1.0299.

All foreign exchange rates have been obtained from the Bank of Canada website. Unless where otherwise noted, these unaudited pro forma consolidated financial statements and their accompanying notes are presented in Canadian dollars.

Prior to the transaction described in Note 3, the Company owned 23,058,585 shares of Augusta which were recorded on the audited consolidated year-end balance sheet of the Company at December 31, 2013 at a fair value of $34,127 (cost of $69,058).

The allocation of the preliminary purchase price to reflect the fair values of the assets acquired and liabilities assumed is based on management’s estimate of such assets and liabilities and, accordingly, the adjustments that have been included in the pro forma consolidated balance sheet may be subject to change. For purposes of these pro forma financial statements, the excess of the purchase price over the estimated fair value of the net assets acquired has been allocated to property, plant and equipment. The final purchase price allocations may differ materially from the allocations included herein.

2Summary of significant accounting policies

These unaudited pro forma consolidated financial statements have been compiled using the significant accounting policies, as set out in the audited consolidated financial statements of the Company as at December 31, 2013. Management has determined, based on their initial assessment, that certain adjustments are necessary to conform Augusta’s audited consolidated financial statements to the accounting policies used by the Company in the preparation of its audited consolidated financial statements:

a)Stock based compensation – Augusta capitalizes stock based compensation related to personnel that service their development project to development costs. Hudbay expenses similar charges to various income statement accounts. The amount of the cumulative impact is unknown at the current time.

b)Deposits and prepayments on long-lead equipment - Augusta presents this as a separate financial statement line item. Hudbay groups these assets within prepaid expenses. An amount of $12,413 has been reclassified to conform to Hudbay policies.

2

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

3The transaction

Proposed transaction

These pro forma financial statements have been prepared on the basis consistent with the terms of the Take-over Bid Circular, but under the assumption that Hudbay acquires 51% of the issued and outstanding common shares of Augusta, including any Augusta Shares held directly or indirectly by Hudbay and its affiliates prior to the Take-over Bid Circular, and any Augusta Shares that may become issued and outstanding after the date hereof but before the expiry time upon the exercise, exchange or conversion of any convertible securities, together with the associated rights issued under the Shareholder Rights Plan.

The transaction will be accounted for as a business combination with Hudbay identified as the acquirer. A summary of the allocation of the preliminary purchase price to the acquired assets and liabilities assumed is as follows:

	$
Preliminary purchase price
Hudbay share consideration (note 4(a(ii)))	160,242
Fair value of Augusta options settled in cash (note 4(f))	5,345
Fair value of Augusta warrants exchanged for Hudbay warrants (note 4(i))	642
Fair value of Augusta shares previously held by Hudbay (note 4(g))	68,276
Total consideration	234,505

The preliminary purchase price has been allocated to the following net assets based on their estimated fair values as of December 31, 2013:

	$	Pro formapresentation$
Assets acquired and liabilities assumed
Cash and cash equivalents (note 4 (c),(f))		14,622
Accounts receivable	8,141
Due from related parties	15
Trade and other receivables		8,156
Prepaids and other	4,544
Deposits on long-lead equipment	12,413
Prepaid expenses and other current assets		16,957
Short-term investments	146
Other financial assets-current		146
Restricted funds	410
Other assets	1,039

3

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

	$	Pro forma presentation $
Other financial assets		1,449
Other assets	1,485
Intangible assets-computer software		1,485
Development costs	193,812
Property, plant, and equipment	91,887
Mineral properties	26,156
Property, plant and equipment		311,855
Current liabilities		(107,365	)
Long-term liabilities		(10,530	)
Deferred tax liabilities		(152,165	)
Unallocated purchase price (note 1)		375,205
Total net assets		459,815
Less: Non-controlling interest		(225,310	)
Total net assets acquired		234,505

The final purchase price and the fair value of the net assets of Augusta to be acquired will ultimately be determined after the closing of the transaction. Therefore, it is likely that the purchase price, including share consideration, and the fair values of assets acquired and liabilities assumed will vary from those shown above. These differences may be material. For purposes of sensitivity, a 10% increase in Hudbay share price is estimated to increase the purchase price by approximately $23,000.

4Pro forma assumptions and adjustments

The unaudited pro forma consolidated financial statements reflect the following assumptions and adjustments to give effect to the acquisition of 51% of the issued and outstanding common shares of Augusta as described in note 3 as if the transactions had occurred on January 1, 2013 for statement of income items and December 31, 2013 for balance sheet items. Assumptions relating to the share price of Hudbay or Augusta have used the date of February 7, 2014 which represents the last trading day before February 10, 2014.

a)i)An adjustment to eliminate the historical equity accounts of Augusta.

ii)An adjustment to reflect the issuance of 17,047,068 Hudbay shares in exchange for 54,117,677 common shares of Augusta representing a share exchange ratio of 0.315 Hudbay share to 1 Augusta share. The closing price of Augusta shares on February 7, 2014 was $2.51. Future movements in share prices may impact the share numbers disclosed within.

iii)An adjustment to reflect the 49% non-controlling interest component of the pro forma adjustments.

4

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

b)An adjustment to reflect the transaction costs related to the transaction, including $7,000 of change of control payments and $13,000 in professional fees.

c)For purposes of pro forma presentation, no adjustment has been made to settle or convert the existing debt on Augusta’s statement of financial position on the assumption that this debt is out-of the money as at February 7, 2014.

On December 16, 2013, Augusta announced that it has closed an additional loan facility for US$26.6 million (the “Expanded Loan”) and has drawn down the first tranche of US$3.5 million. In connection with the Expanded Loan, Augusta paid an arrangement fee of US$1.12 million and issued a total of 3.3 million common share purchase warrants (“Warrants”) to the lender with an exercise price of US$2.12 per share, subject to amendment if certain conditions are not met. The Warrants expire on December 12, 2016.

An adjustment has been reflected in the pro forma consolidated financial statements related to this event as these additional warrants are in-the-money. The impact on the share consideration of the exercise of these warrants is an increase of cash of $6,996 and the issuance of an additional 1,039,500 Hudbay common shares.

d)An adjustment to reflect the fair value of the property, plant, and equipment acquired, in excess of the book value and the resulting deferred tax liability, assuming an income tax rate of 39.6%. The applicable tax rate is based on the tax jurisdiction of the asset where it will be recovered through use.

e)On September 4, 2013, Augusta closed the first tranche for $2,000 of a previously announced financing for a total of $10,000 in convertible unsecured notes. The second tranche of $1,500 closed on September 19, 2013. The third tranche is assumed to have closed on October 25, 2013. The fourth tranche closed on October 25, 2013.  Together, the third and fourth tranche totalled $3,250.

This disclosure is provided for informational purposes only.

f)An adjustment to reflect the cash paid for the fair value of stock options issued by Augusta of $5,345, outstanding as at February 7, 2014 which are estimated to be out of-the-money. The options have been valued using a Black-Scholes model, using the share price of Augusta as at February 7, 2014, and the following assumptions: exercise prices ($2.78 to $4.35), life of options (3.13 to 3.54 years), interest rate (1.13%) and volatility rates (90.8% to 92.2%).

All other options that are estimated to be in-the-money as February 7, 2014, are assumed to be converted into common shares of Augusta, with the corresponding exercise price received as proceeds of $5,214.

5

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

g)An adjustment to re-measure the fair value of the Company’s existing investment in Augusta held prior to acquisition of control. This adjustment is recognized under the “Reserves” account in the pro forma consolidated balance sheet. The investment is designated as an available-for-sale investment by Hudbay, carried at fair value and all fair value changes are recognized in other comprehensive income (OCI), except for other than temporary decline in values recognized in the statement of comprehensive loss.

h)An adjustment to eliminate the Company’s existing investment in Augusta as at December 31, 2013 and an adjustment to eliminate the related accumulated fair value gains (losses) in reserves. Correspondingly, recognized fair value changes in the statement of income are eliminated of $8,314 for the year ended December 31, 2013.

i)An adjustment to reflect the warrants issued by Hudbay in exchange for the warrants issued by Augusta, outstanding as at February 7, 2014. For purposes of pro forma presentation, the warrants issued by Augusta are assumed to be out-of-the money (except for those noted in c) above) and therefore not exercised. Based on the exchange share ratio of Hudbay shares for Augusta shares (note 4(a)) of 0.315 to 1, respectively, 564,386 warrants were issued on February 7, 2014. The warrants have been valued using a Black-Scholes model using the following assumptions: exercise price of $12.22, interest rates of 0.78% to 1.13%, life of warrants of 1.47 to 2.47 years and volatility rates of 40.4% to 40.7%.

An adjustment was also made to eliminate losses arising in the year ended December 31, 2013 from re-measurement of warrants issued by Augusta recognized in its statement of comprehensive income of $100.

j)All unvested restricted shares and restricted share units of Augusta are assumed to vest immediately on February 10, 2014. An adjustment is made for the issuance of the common shares of $2,058.

5Pro forma share capital

	December 31, 2013
	Numberof shares(000s)	$
Hudbay’s common shares outstanding	172,078	1,021,088
Hudbay’s common shares issued under the proposed transaction (note 4(a))	17,047	160,242
Pro forma share capital	189,125	1,181,330

6

Hudbay Minerals Inc.

Notes to Pro Forma Consolidated Financial Statements

(Unaudited) December 31, 2013

(expressed in thousands of Canadian dollars)

6Pro forma loss per share

For the purposes of the unaudited pro forma consolidated financial statements, the loss per share has been calculated using the weighted average number of shares which would have been outstanding as at the year end, after giving effect to the transaction described in notes 3 and 4 as if it had occurred on January 1, 2013.

	December 31,2013$
Actual weighted average number of Hudbay shares outstanding (thousands)	172,048
Assumed number of Hudbay shares issued to Augusta shareholders (note 4(a)) (thousands)	17,047
Pro forma weighted average number of Hudbay shares outstanding - Basic and diluted (thousands)	189,095
Pro forma loss attributable to owners of the Company	(96,358	)
Pro forma loss per share - basic and diluted	(0.51	)

7

SIGNATURES

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

	HUDBAY MINERALS INC.
	By:	/s/Patrick Donnelly
		Name:	Patrick Donnelly
		Title:	Vice President, Legal and Corporate Secretary
Dated: April 17, 2014

EXHIBIT INDEX

(a)(1)(i)          Offer and Circular dated February 10, 2014.**

(a)(1)(ii)         Form of Letter of Transmittal.**

(a)(1)(iii)        Form of Notice of Guaranteed Delivery.**

(a)(1)(iv)        Press release dated February 9, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 10, 2014).**

(a)(1)(v)         Investor relations presentation regarding the Offer dated February 10, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 10, 2014).**

(a)(1)(vi)        Investor relations presentation regarding Constancia Project (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 10, 2014).**

(a)(1)(vii)       Early warning report under National Instrument 62-103 related to the Offer (incorporated by reference to Hudbay’s Form 6-K filed February 10, 2014).**

(a)(1)(viii)      Conference call transcript dated February 10, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 10, 2014).**

(a)(1)(ix)        Newspaper advertisement dated February 11, 2014.**

(a)(1)(x)         Annual Information Form of HudBay Minerals Inc. for the year ended December 31, 2012 (incorporated by reference to Exhibit 99.1 to Hudbay’s Form 40-F (Commission File No. 001-34244) filed with the Commission on March 28, 2013 (the “Form 40-F”)).**

(a)(1)(xi)        Annual Audited Consolidated Financial Statements of HudBay Minerals Inc. for the years ended December 31, 2012 and 2011 and notes and the auditor’s report in respect thereof, together with the credit supporter disclosure filed concurrently therewith (incorporated by reference to Exhibit 99.2 to the Form 40-F).**

(a)(1)(xii)       Management’s Discussion and Analysis of HudBay Minerals Inc. for the financial years ended December 31, 2012 and 2011 (incorporated by reference to Exhibit 99.3 to the Form 40-F).**

(a)(1)(xiii)      Unaudited Interim Consolidated Financial Statements for the Three and Nine Months Ended September 30, 2013, together with the Notes thereto (incorporated by reference to Exhibit 99.1 to Hudbay’s Form 6-K (Commission File No. 001-34244), furnished to the Commission on November 12, 2013).**

(a)(1)(xiv)      Management’s Discussion and Analysis for the Unaudited Interim Consolidated Financial Statements for the Three and Nine Months Ended September 30, 2013 (incorporated by reference to Exhibit 99.2 to Hudbay’s Form 6-K (Commission File No. 001-34244), furnished to the Commission on November 12, 2013).**

(a)(1)(xv)       Notice of Annual and Special Meeting of Shareholders and Management Information Circular dated April 5, 2013 in respect of the Annual and Special Meeting of Shareholders held on May 10, 2013 (incorporated by reference to Exhibit 99.2 to Hudbay’s Form 6-K (Commission File No. 001-34244), furnished to the Commission on April 10, 2013)**

(a)(1)(xvi)      Material Change Report dated February 14, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 14, 2014).**

(a)(1)(xvii)     The press release of HudBay Minerals Inc., dated February 19, 2014, in respect of the announcement of Hudbay’s fourth quarter 2013 financial results (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 19, 2014).**

(a)(1)(xviii)    Annual Audited Consolidated Financial Statements of HudBay Minerals Inc. for the years ended December 31, 2013 and 2012 and notes and the auditor’s report in respect thereof, together with the credit supporter disclosure filed concurrently therewith (incorporated by reference to Exhibits 99.2 and 99.5 to Hudbay’s Form 6-K filed February 20, 2014).**

(a)(1)(xix)      Management’s Discussion and Analysis of HudBay Minerals Inc. for the financial years ended December 31, 2013 and 2012 (incorporated by reference to Exhibit 99.1 to Hudbay’s Form 6-K filed February 20, 2014).**

(a)(1)(xx)       Investor relations presentation regarding Hudbay’s fourth quarter 2013 financial results dated February 20, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 20, 2014).**

(a)(1)(xxi)     Conference call transcript dated February 20, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 20, 2014).**

(a)(1)(xxii)    Interview transcript dated February 20, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 20, 2014).**

(a)(1)(xxiii)    Investor relations presentation dated February 2014 from the BMO Capital Markets 23rd Global Metals & Mining Conference (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 24, 2014).**

(a)(1)(xxiv)   Press release dated February 27, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on February 27, 2014).**

(a)(1)(xxv)    Interview transcript dated March 4, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on March 5, 2014).**

(a)(1)(xxvi)   Notice of Extension and Variation, dated March 14, 2014.**

(a)(1)(xxvii)  Press release dated March 14, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on March 14, 2014).**

(a)(1)(xxviii) Material change report dated March 21, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on March 21, 2014).**

(a)(1)(xxix)   Notice of Variation and Extension dated March 31, 2014.**(a)(1)(xxx) Press release dated March 31, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on March 31, 2014).**

(a)(1)(xxxi)   Investor relations presentation dated April 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on April 3, 2014).**

(a)(1)(xxxii)  Material change report dated April 4, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on April 4, 2014).**

(a)(1)(xxxiii) Press release dated April 14, 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on April 14, 2014).**

(a)(1)(xxxiv) Investor relations presentation dated April 2014 (incorporated by reference to Hudbay’s filing pursuant to Rule 425 on April 14, 2014).**

*Filed herewith.

**   Incorporated by reference.