The proposed Rosemont Mine has won a big victory on the regulatory front, with a new agency decision it no longer needs a federal Clean Water Act permit.
The U.S. Army Corps of Engineers decided Wednesday that the mine no longer is covered by the Clean Water Act because of Trump administration changes to what's been known as the federal "Waters of the U.S." rule.
Those changes, approved in June 2020, meant development of ephemeral washes that only run after storms is no longer regulated under the act.
The Corps says the streams that would be affected by mine construction are mostly ephemeral, and that those that do sometimes carry water have no connection in normal years to rivers such as the Santa Cruz. So now, no permit is needed.
A Clean Water Act permit had been considered a crucial permit for the mine because to build the project, the mining company would have to discharge 42 acres of dredge and fill material from those washes, essentially covering some of them up.
The decision doesn't mean the mine is home free, however. Hudbay Minerals Inc., which proposes to build it in the Santa Rita Mountains southeast of Tucson, still must get a higher court to overturn a U.S. District Court ruling from July 2019. A federal judge in Tucson threw out the U.S. Forest Service's approval of the $1.9 billion project. That case is now awaiting a ruling from the 9th Circuit Court of Appeals.
If Hudbay wins that case, it must also secure federal sign-off on a new biological opinion covering Rosemont's impacts on imperiled species. The District Court also overturned approval of an earlier biological opinion, which must be rewritten because Hudbay only appealed part of the ruling.