Perpetua starts building $1.3B Stibnite gold-antimony mine in Idaho

Perpetua Resources (Nasdaq, TSX: PPTA) has begun early works construction at its $1.3 -billion Stibnite gold-antimony project in central Idaho, fast-tracked by the Trump administration as part of efforts to strengthen the U.S. critical minerals supply chain.

The Stibnite project is to start producing in 2028 roughly 450,000 oz. of gold annually and as much as 35% of America’s demand for antimony, a mineral that’s made headlines this year for China’s export limits. The West lacks supplies to support its use in defence systems, energy storage and semiconductors. 

“Today, we break ground on the Stibnite gold project,” President and CEO Jon Cherry said in a release. “As America’s answer to China’s antimony export bans, we are focused on swiftly and safely bringing our antimony and gold project into development.”  

The project has proven and probable reserves of 148 million lb. of antimony, one of the few domestic sources of the mineral and one of the largest deposits outside China’s control. Stibnite is expected to be among the country’s highest-grade open-pit gold mines. It hods more than 6 million oz. of the yellow metal, which has a spot price of more than $4,000 per oz. that’s attracting global attention. 

Site work

The construction milestone follows the company’s posting of $139 million in financial assurance and confirmation from the U.S. Forest Service that all pre-construction conditions have been met. The service issued its record of decision in January and granted final federal approval in May.

The company is also advancing financing discussions, with preliminary backing from the U.S. Export-Import Bank’s Make More in America and China Transformational Export programs. The proposal includes up to $2 billion in debt financing, with final board review expected in spring 2026.

Shares in Perpetua Resources fell 3.7% by early afternoon Wednesday in Toronto to C$31.98 apiece but they have doubled in value this year. The company has a market capitalization of C$3.45 billion ($2.47 billion).

Mine reclamation

Perpetua plans to create about 950 direct jobs during construction and 550 during operations. After nine years of permitting, CEO Cherry said the project would both deliver critical minerals and restore an abandoned mine site.

“With our reclamation performance bond to reclaim the work we undertake at the project site in place, we officially started early works construction today and are making good on our promises to Idaho and America,” he said.

Perpetua has said the final mine plan was redesigned to shrink the project footprint by 13%, improve stream and wetland conditions, and reconnect fish habitats. The company has pledged to restore legacy environmental damage from past mining activity in Idaho’s Stibnite-Yellow Pine district, about 222 km northeast of Boise.

Despite these measures, the Nez Perce Tribe has opposed the project, citing potential risks to salmon populations and downstream ecosystems.

The site was a key antimony supplier during the Second World War and now hosts 104.6 million proven and probable tonnes grading 1.43 grams gold per tonne and 0.064% antimony, for a total of 4.8 million oz. of gold and 148 million lb. of antimony, according to 2020 feasibility data.