The U.S. Department of Defense has awarded another round of funding to advance Perpetua Resources’ Stibnite mine in eastern Valley County.
The Boise mining company announced today that it received up to $6.9 million to continue developing plans for processing antimony from Stibnite into military munitions.
Specifically, the money will expand antimony sampling and increase the size of a modular processing plant being developed for the U.S. Army, according to the company.
“We are honored to continue our work with the U.S. Army to secure a domestic source of antimony trisulfide,” Perpetua President and CEO Jon Cherry said. “Advancing America’s capabilities to process minerals critical to national defense is essential for our long-term mineral independence and resilience.”
The additional funding builds on $15.5 million Perpetua was awarded in 2023 by the Defense Department to develop a “ground-to-round” domestic supply chain for antimony.
Overall, Perpetua has received more than $80 million in funding from the Defense Department since 2022, including nearly $60 million to cover general expenses associated with permitting the Stibnite mine.
Critical mineral designation
The Defense Department’s continued interest in the Stibnite mine follows the federal government’s 2018 designation of antimony as “critical” to the country’s economic and national security.
Perpetua estimates the Stibnite mine could yield about 106 million pounds of antimony. It would be the only mine in the United States that produces the mineral and could provide up to 35% of national demand for antimony in the first six years of mining, according to Perpetua.
The antimony would be used by the Defense Department for munitions, mortars, artillery, mines, flares, grenades and missiles.
“Antimony trisulfide is an essential and non-replaceable component to over 300 types of munitions, making it important to source in America,” said Col. Steven Power of the Picatinny Arsenal, a military research and manufacturing facility in New Jersey.
“Establishing a fully domestic supply chain of this critical mineral is foundational to keeping America’s warfighters safe,” Power said.
China, Russia, and Tajikistan produced about 79% of all mined antimony in 2023, according to data from the U.S. Geological Survey.
In December, China, which is the world’s leading antimony producer, banned exports of the mineral to the United States.
Despite the political benefits of antimony to Perpetua, 4.2 million ounces of gold that the Stibnite mine is expected to produce would account for more than 90% of the mine’s projected revenue.
Construction timeline
Earlier this year, Perpetua’s mining proposal was approved by the Payette National Forest, the lead permitting agency on the mine.
However, the company still needs to obtain a few permits from the state and assemble a financing package that guarantees site clean-up work is funded, said Marty Boughton, a Perpetua spokesperson.
Without donors like you, this story would not exist.
Make a donation of any size here
Construction of the mine, which is expected to take up to three years, could still begin as soon as this summer, Boughton said.
The company recently applied for $2 billion in construction funding financed by the Export-Import Bank of the United States. Boughton said it could take months for that application to be processed.
Precious metals at Stibnite would be extracted from three open pit mines totaling about 473 acres within the 1,740-acre project zone, which is about three miles from the Frank Church – River of No Return Wilderness.
Opponents of the mine fear it could pollute the East Fork South Fork Salmon River, which flows through the project site, and cause other environmental damage.
A lawsuit filed by conservation groups that say the Payette’s approval of the mine violates federal environmental laws remains pending in U.S. District Court.
