Court Upholds Perpetua’s Stibnite Gold Approvals

A federal judge has upheld the core federal approvals behind Perpetua Resources’ Stibnite Gold Project in central Idaho, rejecting most of an environmental coalition’s legal challenge and clearing the way for construction to keep moving at the gold-antimony site.

At a glance

• On August 18, 2026, the U.S. District Court for Idaho upheld the Forest Service’s approval of Stibnite, rejecting challenges brought under the National Environmental Policy Act and the National Forest Management Act.
• Judge Amanda Brailsford found narrow gaps in the Forest Service’s Endangered Species Act paperwork for bull trout and wolverines, and sent that one piece back for a fix rather than reopening the whole approval.
• Construction keeps running while the fix is made: autoclave components are being built in Europe, permanent worker housing is going up, and an access road and processing pad are under construction.
• Plaintiffs, a coalition including the Idaho Conservation League, Idaho Rivers United, and the Center for Biological Diversity, have appealed the ruling.
• Perpetua has also drawn more than $87 million in U.S. Department of War and Army funding, on top of a $2.9 billion Export-Import Bank loan approved in May 2026.

What did the plaintiffs argue, and what did the judge decide?

The environmental coalition, which also included Save the South Fork Salmon, Idaho Rivers United, Earthworks, and American Rivers, sued to block Stibnite’s federal approvals, arguing the Forest Service had not done enough to protect the South Fork Salmon River watershed and the species living in it. Judge Brailsford’s ruling sided with the Forest Service on nearly every count, finding the agency’s environmental review adequate under NEPA and its forest management decisions sound under the National Forest Management Act.

The one piece she did not clear was narrower than a permit reversal: the “incidental take statements” covering bull trout and wolverines did not spell out, in her words, when rising water temperatures would count as harm to bull trout or what would trigger a fresh look at wolverine impacts. She called the gaps fixable, since the missing detail already sits in the administrative record, and ordered the Forest Service to amend the statements rather than restart the review. Perpetua’s own update on the ruling confirms construction continues while that remand plays out, and notes the plaintiffs have filed an appeal.

Why does a mine in Idaho’s backcountry keep drawing federal money and legal fights?

Stibnite is not just another gold mine. During World War II, the district supplied up to 90 percent of the antimony used in U.S. munitions and roughly half its tungsten, then sat idle and unreclaimed for decades. Perpetua’s plan pairs a gold mine, expected to produce 463,000 ounces a year in its first four years, with what would become the country’s only primary domestic antimony source, a metal the United States currently imports almost entirely from China, Russia, and Tajikistan. That dependency is why the project draws Defense Production Act funding and Export-Import Bank financing, and why permitting delays here matter beyond one company’s balance sheet. Our Idaho master report and Stibnite tour stop cover the district’s wartime history and its second act in full.

The same federal interest cuts both ways in court. Environmental groups argue a project moving this fast on national-security grounds still needs a full accounting of its impact on salmon, bull trout, and wolverines in the watershed. The ruling did not dismiss those concerns outright, it separated the record’s adequate parts from the one piece that was not, letting both sides claim a piece of this decision.

What happens next at Stibnite?

With the appeal pending but no injunction in place, Perpetua’s construction schedule keeps running. The company reports roughly half of its permanent modular housing units delivered as of late August, ongoing work on the Burntlog access route and administrative pad, and four rigs running toward a planned 10,000 meter exploration program. An antimony processing pilot plant at Idaho National Laboratory opened in July to test samples from the site, a step toward proving out domestic processing alongside domestic mining. A final investment decision is expected later in 2026, with first gold production targeted for 2029. The pending appeal remains a real, if narrower, risk than before this ruling.

Gold and antimony rarely show up in the same headline, but Stibnite is the reason they do in Idaho: one ore body, two federally designated critical outputs, and now one court record that both sides are still arguing over.