TUCSON, Ariz.— U.S. District Judge Raner C. Collins will hear arguments Nov. 3 in Tucson on a request to halt South32’s Hermosa mine expansion onto public land in southern Arizona’s Patagonia Mountains while a lawsuit challenging the project proceeds.

The Center for Biological Diversity and Patagonia Area Resource Alliance are seeking a preliminary injunction as part of their lawsuit against the U.S. Forest Service and U.S. Fish and Wildlife Service. The lawsuit says the agencies failed to adequately evaluate threats to endangered species, groundwater and other public resources before approve the mine expansion.

What: Oral argument before U.S. District Judge Raner C. Collins on a motion to halt the Hermosa mine expansion, and a supporter rally.

When: Tuesday, Nov. 3, 2026. Rally calling for protection of the Patagonia Mountains’ wildlife, water and communities from 12:15 to 12:45 p.m. MST. Hearing begins at 1:15 p.m.

Where: Rally outside the federal courthouse at 405 W. Congress St., Tucson, AZ 85701. Hearing in Courtroom 6D.

Who: The Center for Biological Diversity, Patagonia Area Resource Alliance and supporters of protecting the Patagonia Mountains.

Background

The Center for Biological Diversity and Patagonia Area Resource Alliance sued the Trump administration over its Sept. 2 approval of South32’s Hermosa mine expansion onto federal public lands in southern Arizona.

The approvals would expand industrial mining activities across more than 52,000 acres of public land in the Coronado National Forest for 83 years. The lawsuit says the agencies violated the Endangered Species Act by failing to adequately evaluate threats to protected species and their designated critical habitat. It also says the Forest Service violated the National Environmental Policy Act by failing to adequately analyze the project’s threats to groundwater and other public resources.

The Patagonia Mountains are a refuge for endangered jaguars and ocelots moving between northern Mexico and southern Arizona. They also contain habitat vital for threatened Mexican spotted owls and western yellow-billed cuckoos and harbor rare plants including Bartram’s stonecrop and beardless chinchweed.

The mine expansion would bring industrial development deep into the public forest, including a 225-acre tailings facility capable of holding up to 38 million tons of mining waste, a 7.6-mile permanent access road, 7.2 miles of new power transmission lines, potentially hundreds of exploratory drill holes and six groundwater wells. Groundwater pumping could lower the water table by as much as 250 feet, potentially reducing or eliminating flows in seeps and springs that sustain wildlife.