Augusta Resource Announces Rosemont Copper EIS Delivered

Published: July 1, 2013

By Augusta Resource Corporation

TORONTO, July 1, 2013 — /PRNewswire/ - Augusta Resource Corporation (TSX/NYSE MKT: AZC) ("Augusta" or "the Company") is pleased to announce that the Preliminary Administrative ("PA") Final Environmental Impact Statement ("FEIS") for Rosemont Copper has been delivered by the U.S. Forest Service ("USFS") to the Federal, State and Local cooperating agencies for their final comments today. This follows a detailed internal review by the regional and Washington, D.C. offices of the USFS. The cooperating agencies have been given 30 days to provide their final comments, following which the FEIS will be finalized and issued.

The PA FEIS includes a description of the environmental impacts of the Rosemont Copper Project, including impacts to water and air quality, cultural resources, recreation and wildlife. This discussion includes the results of consultation with the U.S. Fish and Wildlife Service ("USFWS"). The PA FEIS concludes, supported by the USFWS, that the project would not jeopardize the continued existence of any of the ten federally listed (threatened and endangered) species that may occur in the project area. The PA FEIS also concludes that the project will not result in adverse modification of any designated critical habitat. Further, as anticipated and planned for, certain monitoring and mitigation requirements will be required to minimize the impacts of the project.

"The Rosemont Mine Plan of Operations and associated mitigation programs are comprehensive, progressive, and thorough," commented Jamie Sturgess, Augusta's Senior Vice President, Corporate Development and Government Affairs. "The issues and concerns of many parties have been addressed, through careful project facility siting, technology selection, pollution prevention, land and water set-asides, compensatory mitigation funding, community endowment efforts, and voluntary acquisition of ranches and rare surface water rights for preservation of habitat values."

The USFS is also completing the Record of Decision ("ROD") with the objective of issuing the ROD concurrently with the publication of the FEIS. Augusta expects both of these events to occur in the third quarter of 2013.

In addition, the Army Corps of Engineers (ACOE) Section 404 permit continues to advance. The ACOE will use the FEIS to finalize the impacts and mitigation requirements for the Rosemont Project. Receipt of this last required permit is expected shortly after the ROD and publication of the FEIS.

"The USFS remains focused on moving the permitting process forward towards completion," said Gil Clausen, Augusta's President and CEO. "This year will be a transformative year for Augusta and our project partners as we move from permitting into construction at Rosemont. Our team is fully prepared and ready to execute on its development. Project financing is moving rapidly to conclusion and detailed construction engineering and procurement is well advanced."

ABOUT AUGUSTA Augusta is a base metals company focused on advancing the Rosemont Copper www.heraldonline.com/2013/07/01/4991404/augusta-resource-announces-rosemont.html 1/3

7/1/13 TORONTO, July 1, 2013: Augusta Resource Announces Rosemont Copper EIS Delivered to Cooperating Agencies for Final Comments | PRNewswire | Rock Hill...

deposit near Tucson, Arizona. Rosemont hosts a large copper/molybdenum reserve that would account for about 10% of US copper output once in production (for details refer to www.augustaresource.com). The exceptional experience and strength of Augusta's management team, combined with the developed infrastructure and robust economics of the Rosemont project, propels Augusta to becoming a solid mid-tier copper producer. The Company trades on the Toronto Stock Exchange and the NYSE MKT under the symbol AZC.