CuMo Mine Exploration Follow-Up

June 25, 2025 – Advocates for the West and Idaho conservation groups filed suit against the U.S. Forest Service for its approval of a mine exploration project on public lands in the headwaters of the Boise River. The CuMo Mine Exploration Project threatens critical clean water, fish and wildlife habitat, and the rare plant Sacajawea’s bitterroot. Despite overwhelming public opposition, the Forest Service in March approved the four-year plan by Idaho Copper Corporation to build nearly nine miles of new roads, clear 122 drill pads, and drill 250 bore holes across 2,617 acres of National Forest public lands adjacent to Grimes Creek, a tributary to Mores Creek and the Boise River.

Twice before, courts have struck down variations of the project due to the risks it posed to water quality and sensitive species. A federal court struck down the project in 2012 because the Forest Service failed to adequately assess the risks that extensive underground drilling could contaminate groundwater. The court struck it down again in 2016 because of the project’s threats to Sacajawea’s bitterroot.

Through the project, Idaho Copper hopes to find sufficient copper and molybdenum to excavate one of the largest open-pit accessible molybdenum mines in the world. The exploration site is upstream of half of Idaho’s population, and the Boise River watershed provides approximately 30 percent of Boise’s drinking water supply and irrigates over 300,000 acres of farmland.

The Grimes Creek watershed and surrounding public lands are home to imperiled and sensitive species such as wolverines, bull trout, great gray owls, flammulated owls, goshawks, and the rare Sacajawea’s bitterroot—the largest known populations of which occur within the project site.

Last year, the Forest Service received more than 1,200 public comments on the CuMo Mine Exploration Project’s draft environmental review, with over 99% of them opposed to the project.

Recent changes in ownership of Idaho Copper and financial struggles also have raised concerns about the project’s future management and environmental oversight, especially given recent staffing cuts impacting the Boise National Forest. Last year, Idaho Copper was forced into a transition in ownership through a sheriff’s sale, resulting in a Hong Kong-based investment company as the new majority shareholder.

The conservation groups are represented by Advocates for the West and Roger Flynn of the Western Mining Action Project.