Perpetua Resources (Nasdaq: PPTA) (TSX: PPTA) announced Monday that the United States Army Corps of Engineers (USACE) has issued Perpetua’s Clean Water Act Section 404 permit for the Stibnite Gold project in Idaho.
The decision comes after eight years of rigorous inter-agency federal permitting, and was the last federal permit required to progress towards construction.
The Stibnite project, with its recently secured record of decision from the US Forest Service, is uniquely positioned to supply the critical mineral antimony, which is essential to national security and energy technology, the company said.
Antimony, classified as a critical mineral essential for technology, defense, and energy applications, is imported into the US as there is currently no domestic production. China accounted for 60% of globally mined antimony in 2024, according to data from the US Geological Survey.
Last year, China banned exports of the metal to the US.
The Stibnite project holds an estimated 148-million-pound antimony reserve — the only identified antimony reserve in the US and one of the largest reserves outside of Chinese control.
It is estimated the project could meet about 35% of U.S. antimony demand during its initial six years of production, based on the 2023 USGS antimony commodity summary.
The company said the project is also projected to be one of the highest-grade open-pit gold mines in the United States, with gold reserves of approximately 4.8 million ounces, and is expected to produce approximately 450,000 ounces of gold annually over its first four years of production.
“Today’s final federal permit from the Army Corps marks the culmination of eight years of permitting, scientific study, project refinement, and lots of hard work,” Perpetua Resources CEO Jon Cherry said in a news release. “We are immensely proud to achieve this milestone. It’s time to move forward and take the Stibnite Gold project into a new and exciting phase of development.”
Reviving a historical mining district
The Stibnite Gold Project is also designed to redevelop the historical Stibnite Mining District for gold, silver and antimony, while conducting environmental restoration to rehabilitate the abandoned site. Perpetua’s vision to “Restore the Site” is a central tenet of the approved mine plan.
The project, the company said, is designed to remove, reprocess, and safely store legacy tailings and waste to improve water quality, restore the natural flow of the headwaters of the Salmon River and reopen fish passage to miles of critical spawning habitat that have been blocked for over 80 years and provide a net increase in wetland acres and an uplift in wetlands quality.
Perpetua Resources began the formal permitting process under the National Environmental Policy Act (NEPA) in 2016. The US Forest Service issued a Draft Environmental Impact Statement in 2020, a Supplemental Draft Environmental Impact Statement in 2022, a Final Environmental Impact Statement and Draft Record of Decision in September of 2024, and a Final Record of Decision in January 2025.
In April, the project was selected by the Trump Administration as a Transparency Project in response to its March 2025 Executive Order to bolster American mineral production and was included on the Federal Permitting Improvement Steering Council FAST-41 dashboard.
Perpetua said it is now focused on finalizing the remaining state permits and securing project financing needed to begin construction.
Perpetua Resources stock closed the day up 6.95% on the Nasdaq. The company has a $913.6 million market capitalization.