Key U.S. Antimony Mine Advances Towards Restart With EXIM Loan

Perpetua Resources announced on March 31, 2026 the unanimous agreement by the board of the U.S. Export/Import Bank (EXIM Bank) to notify Congress of a $2.7 billion loan to advance development of the company’s Stibnite Gold Mine in central Idaho. It’s a major step towards restarting a mothballed mine which once supplied 90% of U.S. needs for antimony, a critical mineral which goes into an array of high-tech products, renewable energy, and Pentagon weapons systems.

“Today’s decision marks the final phase of EXIM approval,” said Jon Cherry, President & CEO of Perpetua Resources said in the company’s release. “We’ve worked diligently with U.S. EXIM for over two years on a financing solution aimed at strengthening America’s supply chains, creating jobs right here at home, and fortifying national security.” The announcement comes six months after Perpetua held a joint ribbon-cutting ceremony with state and Pentagon officials marking its having obtained final permitting approval to move forward with construction required to restart the mining operations at the Stibnite site.

A Long History of Plentiful Antimony Supply

Though known to contain sizable quantities of an array of minerals, including gold and silver, the Stibnite mine’s reserves of the critical mineral antimony is the main prize the Pentagon hopes to secure from its operations. In documents filed during its years-long permitting process with the U.S. Forest Service, Perpetua estimates the mine’s ore contains as much 4.8 million ounces of gold, 6.4 million ounces of silver, and 149 million pounds of antimony. The overall mining site covers 3,200 acres of land including 3 pit mining sites.

Crucially, Perpetua estimates the Stibnite mine could enhance U.S. energy security and national security by providing up to 35% of U.S antimony needs in the coming decades. That’s an estimate grounded in reality. The Stibnite Mine, first established more than a century ago as a pure gold mining operation, became a key part of Franklin Roosevelt’s “arsenal of democracy,” supplying 90% of America’s huge antimony needs during World War II. The mine went dormant in the 1990s, but Perpetua has spent the last decade-and-a-half working its way through the federal permitting process required to get it restarted.

Cherry points out that the finalization of the EXIM Bank loan moves the ball forward to its goal of making a final investment decision later this year. The company also published updated project economics as part of its release. “Assuming a $4,500/oz gold price, the updated model reports Stibnite’s unlevered, after-tax project NPV of $6.1 billion and after-tax IRR of 32.3% reaffirming Stibnite as a premier gold antimony project,” Cherry says.

An Insulated Stream of Domestic Antimony Supply

The update highlights one of the Stibnite project’s major advantages: The fact that its antimony is recovered along with the mine’s gold production – the two valuable minerals must be separated from one another in the post-production process. It’s a unique feature which insulates the Stibnite Mine from any future effort by the Chinese government to collapse antimony prices by flooding the market, one which helps explain why the Trump Administration – especially the Pentagon – has taken such an interest in ensuring the mine is successfully restarted.

Maj. Gen. John T. Reim, Joint Program Executive Officer Armaments & Ammunition and Picatinny Arsenal Commanding General made the Pentagon’s interest clear at last year’s ribbon cutting. “The Stibnite project currently holds the largest identified reserve of antimony in the U.S. It is one of the largest antimony reserves outside of foreign control,” he told the gathering. “This mine offers a secure, reliable, domestic resource for military grade antimony sulfide and is aligned with the Army’s ongoing ‘Ground-to-Round’ assured munitions strategy for establishing a complete domestic supply chain, from raw material access to material processing to ammunition production.”

With approval of the EXIM Bank’s loan, Perpetua is one step closer to re-establishing that desired domestic the supply chain for antimony. It’s a goal which has been a long time coming.