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News Releases from Region 09

EPA Seeks Comment on Gunnison Copper Project Proposed Permit

Contact Information: 
Nahal Mogharabi (

SAN FRANCISCO – The U.S. Environmental Protection Agency is seeking public comment on a draft Underground Injection Control (UIC) permit and aquifer exemption for Excelsior Mining Arizona, Inc. (Excelsior).  The permit, if approved, would allow the company to construct and operate a copper production facility.  The proposed 332-acre Gunnison Copper Project is in Cochise County, between Benson and Willcox, Arizona.

EPA is seeking public comment on the draft permit and the proposed aquifer exemption.  The permit, if approved, would authorize Excelsior to inject a solution into the copper orebody, approximately 400 – 1400 feet underground, to produce copper. The draft permit would allow the company to drill wells, extract copper in solution and restore the aquifer over 20 years.  After the 20-year operational period, Excelsior would be required to properly close the wells, continue aquifer restoration for three additional years, and monitor the aquifer for at least five more years.

The aquifer qualifies for exemption because it does not serve as a source of drinking water and it contains commercially producible minerals. The draft permit would require the company to contain all injection associated with the copper production facility within the exempt portion of the aquifer to ensure protection of the surrounding groundwater.   

To view the draft permit and aquifer exemption, please visit or the Elsie S. Hogan Library, 100 North Curtis Ave., Willcox, Arizona 85643.

Comments should be mailed, faxed or emailed by January 8, 2018 to:

U.S. Environmental Protection Agency, Region 9
Drinking Water Protection Section, Mail Code WTR-3-2
75 Hawthorne Street
San Francisco, CA 94105
Attention: Nancy Rumrill
Telephone: (415) 972-3293