The Arizona Department of Environmental Quality Wednesday issued the final state environmental clearance for Rosemont Copper Mine.
The state granted the mining company a conditional water quality certification for its proposed mine in the Santa Rita Mountains south of Tucson. The certification will allow the mining company to move some of the extracted dirt from its proposed open pit mine into nearby canyons.
The review is required by the federal government, said Linda Taunt, a technical adviser on water quality for the Arizona Department of Environmental Quality.
"There's a section in the Clean Water Act that requires states to review federal permit applications or federal licenses to make sure that water quality standards are going to be protected," she said.
ADEQ evaluated the plan for downstream runoff in a few of the watersheds in the Santa Ritas, Taunt said.
“That’s what we were looking at, is placing the waste rock and the tailings in those drainages," she said. "How is that going to impact the surface waters immediately downstream, and then most importantly Davidson Canyon and Cienega, which are outstanding Arizona waters, further downstream?"
The certification is conditional because it will require Rosemont to make some changes to its plans, she said. One such condition is a restriction on dumping mine material into a watershed.
"We believe with the conditions that we've included, that the downstream waters will be protected," Taunt said said.
If the mining operation violates the terms of the certification, it could be revoked.
This state certification will be included with Rosemont’s application for federal environmental clearance, known as a 404 permit, from the Army Corps of Engineers.
"It doesn’t really allow Rosemont to go out and do anything because they still need to get their 404 permit issued by the Corps," Taunt said.