U.S. Environmental Protection Agency: Rosemont mine would cause “substantial and unacceptable impact” to southern Arizona water supplies

Chalk up a potential reprieve for the Santa Cruz valley watershed and clean drinking water! On November 7th, the U.S. Environmental Protection Agency (EPA) issued a letter to the U.S. Army Corps of Engineers recommending denial of a Clean Water Permit for the operation that would allow the Augusta Resource Corporation to dump potentially toxic mine waste from the proposed Rosemont Mine into area waterways. This could play a major role in altering or halting proposed mine construction, as the EPA has ultimate veto authority over the Corps of Engineers’ 404 Clean Water Act permitting process. The permit can only be issued if the proposed mine meets Clean Water Act Standards and is required before any construction can begin.

The proposed open pit copper mine would be located south of Tucson in the Santa Rita Mountains. The mile-wide and half-mile deep operation, on Rosemont’s in-holding located within the Coronado National Forest and impacting thousands of acres of forest lands, would have devastating effects on biologically sensitive areas, including Las Ciengas National Conservation Area. Endangered species, such as the southwest willow flycatcher and chiricahua leopard frog, rely on the riparian areas found in the Las Cienegas watershed for survival. The proposed mine would severely impact these and many other sensitive species by potentially poisoning water sources and restricting water flow.

The EPA reached its decision based on detailed analysis that concluded Rosemont’s mitigation plan to be “scientifically flawed” and “grossly inadequate” to combat the mines permanent negative effects to water sources and the ecosystem.  The EPA advised the Corps of Engineers that the project “should not be permitted as proposed”.

The EPA was very critical of all aspects of Rosemont’s mitigation plan and deemed it “insufficient to avoid ‘significant degradation’ of the aquatic ecosystem.’” Furthermore, “(t)he pit will permanently reverse the natural direction of groundwater flow toward and into the mine pit, and away from the sensitive aquatic habitats in Las Cienegas NCA and Cienega Creek Natural Preserve,” the EPA letter states. The EPA also indicates that while the mitigation plan may be sufficient for smaller projects (“e.g., flood control or highway projects”) it is unacceptable for the potential impacts of the proposed mine.

It the midst of all this, Augusta Resource, Rosemont Copper’s Canadian parent company, is facing financial crisis. Stocks are remaining at a 52-week low and the company has less than $1 million is cash reserves as of September 30th according to regulatory filings released last week. These monetary issues raise questions about whether Rosemont even has the funds to address the numerous concerns and criticisms the EPA has about the Clean Water Act Permit.

The full letter can be downloaded here.

Please also visit Save the Scenic Santa Ritas for more information!