2001 photo of Copper Flat

By Allyson Siwik
Gila Resources Information Project and Chapter Water Committee

The Bureau of Land Management in November issued a Draft Environmental Impact Statement for the Copper Flat copper mine in Hillsboro, Sierra County, N.M. The agency has extended the public comment period by 45 days and requests comments by March 4.

The New Mexico Copper Corporation proposes re-establishing a poly-metallic mine and processing facility near Hillsboro. The operation would produce copper concentrate with gold and silver, as well as molybdenum concentrate. Quintana Mineral Corp. operated the mine for three and a half months in 1982.

The 2,190-acre project would use BLM-managed public land and private property. It consists of an open-pit mine, flotation mill, tailings-storage facility, disposal areas for waste rock, ore stockpiles and other ancillary facilities. The preferred alternative will process 30,000 tons of material per day, and the mine is expected to have a 12-year mine life.

BLM held two public meetings in December in Hillsboro and Truth or Consequences to answer questions about the proposal and accept public comment. Residents from Hillsboro, located about 5 miles from the mine site, attended the public meeting. Many made oral comments and were uniformly opposed to the mine proposal.

Community concerns ranged from impairment of water quality and quantity to negative impacts on tourism and the economy, increased traffic, and impacts to wildlife.

Water use under the proposed alternative is estimated to be 22,000 acre-feet per year, with a portion of water use coming from recycled water from the tailings-storage facility. The State Engineer has approved water rights for the company for 888 acre-feet per year, calling into question the viability of the project. Moreover, withdrawals from the company’s wells are anticipated to cause depletions from Caballo Lake and the Rio Grande. A pit lake is expected to gradually form in the open pit once mining ceases. Since the geochemistry work is not completed yet, it is unknown if that pit lake will be acidic, requiring treatment in perpetuity. Up to 19 trucks per day would use Highway 152, the main roadway from Interstate 25 to the Gila National Forest and Silver City, potentially causing traffic problems.

To review the Draft Environmental Impact Statement, visit the BLM Copper Flat information page. Public comments should be submitted to BLM by March 4 via email to BLM_NM_LCDO_Comments@blm.gov.

The Rio Grande Chapter will send an action alert for comments. Contact riogrande.chapter@sierraclub.org to be added to the update list on mining issues.

Comment on Copper Flat due March 4