The U.S. Environmental Protection Agency recommended that the proposed Rosemont Copper mine should not get a water permit, amid recent agency analysis that concluded mine would not be doing enough to prevent water damage in the area.

A letter by the EPA said the mine, which would lie within the Cienega Creek watershed around the Santa Rita Mountains, could result in the fragmentation of an intact natural hydrologic landscape unit, reverse groundwater flow direction, and cause permanent regional drawdown of groundwater.

Agency also explained that proposed activities by Rosemont to mitigate water damage would not be sufficient.

"These impacts would be direct consequences of the Clean Water Act 404 permit action under the consideration by the (U.S. Army Corps of Engineers), and represent a large and permanent change in the regional ecology of the Cienega Creek watershed to significantly drier, less biologically diverse stream and riparian condition," the letter said.

The EPA's recommendation to deny Rosemont's permit application is potentially devastating to the project, because the agency has veto authority over the permit, said a press release from the Save the Scenic Santa Ritas.

"The EPA letter refers to old plans and issues which were the basis of discussion and not decision," Rosemont's parent company, Augusta Resources Corp., said in a press release. "The ACOE (Corps of Engineers) will make their decisions based on facts, rules and regulations as they continue to maintain good dialog with the EPA."

Rosemont has proposed an open pit mine on the northeastern slope of the Santa Rita Mountains. It has said the mine’s buildout and operation would create 2,900 jobs and inject $19 billion into the state’s economy.