Stibnite Gold-Antimony Mine in the US Receives Approval from USACE

According to a report on Mining.com, Perpetua Resources announced on Monday that its Stibnite (stibnite ore) antimony-gold project in Idaho had received a permit from the US Army Corps of Engineers (USACE) under Section 404 of the Clean Water Act.

This decision, made after eight years of rigorous review by federal agencies, represents the final federal permit required for the project to proceed to construction.

The company stated that the Stibnite project, which recently received approval from the US Forest Service (USFS), is now ready to produce antimony, a critical mineral essential for national security and energy technologies.

Antimony is classified by the US as a critical mineral vital for high-tech, defense, and energy sectors, as there is currently no domestic production in the country.

With antimony reserves of 148 million pounds (approximately 67,000 mt), the Stibnite project is the only large antimony mine discovered in the US to date and one of the largest in the world.

According to the US Minerals Yearbook 2023 antimony data, the project is expected to meet 35% of the US's antimony demand within six years of production.

The company also stated that the project is one of the highest-grade open-pit gold mines in the US, with gold reserves of approximately 4.8 million ounces, capable of producing 450,000 ounces of gold annually in the first four years of production.

"Today's final federal permit from USACE is the culmination of eight years of permit applications, scientific research, project optimization, and extensive work," said Jon Cherry, CEO of Perpetua Resources, in a press release. "We are thrilled to reach this milestone. It's time to advance the Stibnite gold project into its next phase of development."

The Stibnite gold project also aims to rehabilitate this historic antimony mining district, redevelop gold, silver, and antimony ore resources, and conduct environmental restoration to rehabilitate abandoned sites. The company's vision of "restoring the mine site" was a significant factor in the project's approval.

Perpetua Resources stated that the project aims to remove, reprocess, and safely store legacy tailings and waste to improve water quality, restore the natural flow of the Salmon River's headwaters, reopen miles of fish passage to critical spawning habitats that have been blocked for over 80 years, and increase wetland acreage and quality.

In 2016, the company formally submitted its permit application under the National Environmental Policy Act (NEPA). In 2020, the USFS released a draft Environmental Impact Statement (EIS), followed by a Supplemental EIS in 2022, a Final EIS and Draft Record of Decision in September 2024, and a Final Record of Decision in January 2025.

In April, in accordance with Trump's executive order in March 2025 to support the production of mineral products in the US, the project was selected by the Trump administration as a transparency project and included in the FAST-41 list of the Federal Permitting Improvement Steering Council.

Perpetua Resources stated that its current focus was on completing the remaining state permits and securing the necessary funding for project construction.