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Independent Auditors’ Report on Internal  Controls under Standardsof the Public Company Accounting Oversight  Board (United States)



To the Shareholders of Augusta  Resource Corporation

We have audited Augusta Resource  Corporation’s (the “Company”) internal control over financial reporting as at  December 31, 2009, based on criteria established in Internal  Control—Integrated Frameworkissued by the Committee of Sponsoring  Organizations of the Treadway Commission (“the COSO criteria”). The Company’s  management is responsible for maintaining effective internal control over  financial reporting, and for its assessment of the effectiveness of internal control  over financial reporting included in the accompanying Management’s assessment  of internal control over financial reporting. Our responsibility is to express  an opinion on the Company’s internal control over financial reporting based on  our audit.

We conducted our audit in accordance  with the standards of the Public Company Accounting Oversight Board (United  States). Those standards require that we plan and perform the audit to obtain  reasonable assurance about whether effective internal control over financial  reporting was maintained in all material respects. Our audit included obtaining  an understanding of internal control over financial reporting, assessing the  risk that a material weakness exists, testing and evaluating the design and  operating effectiveness of internal control, and performing such other  procedures as we considered necessary in the circumstances. We believe that our  audit provides a reasonable basis for our opinion.

A company’s internal control over  financial reporting is a process designed to provide reasonable assurance  regarding the reliability of financial reporting and the preparation of  financial statements for external purposes in accordance with generally  accepted accounting principles. A company’s internal control over financial  reporting includes those policies and procedures that (1) pertain to the  maintenance of records that, in reasonable detail, accurately and fairly  reflect the transactions and dispositions of the assets of the Company; (2)  provide reasonable assurance that transactions are recorded as necessary to  permit preparation of financial statements in accordance with generally  accepted accounting principles, and that receipts and expenditures of the Company  are being made only in accordance with authorizations of management and  directors of the Company; and (3) provide reasonable assurance regarding  prevention or timely detection of unauthorized acquisition, use or disposition  of the Company’s assets that could have a material effect on the financial  statements.

Because of its inherent limitations,  internal control over financial reporting may not prevent or detect  misstatements.  Also, projections of any  evaluation of effectiveness to future periods are subject to the risk that  controls may become inadequate because of changes in conditions, or that the  degree of compliance with the policies or procedures may deteriorate.

In our opinion, the Company  maintained, in all material respects, effective internal control over financial  reporting as of December 31, 2009, based on the COSO criteria.

We have also audited, in accordance  with Canadian generally accepted auditing standards and the standards of the  Public Company Accounting Oversight Board (United States), the consolidated  balance sheets as at December 31, 2009 and 2008 and the consolidated statements  of shareholders’ equity, operations, comprehensive loss and cash flows for each  of the years in the three-year period ended December 31, 2009 of the Company  and our report dated March 25, 2010 expressed an unqualified opinion on those  financial statements.



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|March 25, 2010
    Vancouver,  Canada | Ernst & Young LLPChartered  Accountants

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