The U.S. Army is moving to strengthen domestic supply chains for critical defense minerals by backing a new generation of small, mobile refining units, starting with antimony sourced from Perpetua Resources’ (Nasdaq: PPTA; TSX: PPTA) $1.3-billion Stibnite gold-antimony project in Idaho.
The Army has invested roughly $30 million in the development of a modular antimony refinery that can be transported in four standard shipping containers. The unit is designed to produce between 7 and 10 tonnes per year of antimony trisulphide, a key input for ammunition primers, detonators and ignition systems. While modest in scale, the system is intended to demonstrate a flexible refining model that could be deployed rapidly and replicated as demand grows.
In parallel, Idaho National Laboratory (INL) is preparing to host a separate pilot plant for Perpetua that will process ore from the Stibnite project, located about 150 km northeast of Boise. The pilot facility will focus on refining antimony trisulphide suitable for defense and advanced military applications, as well as generating technical data to support future commercial-scale operations.
Analysts say the initiative reflects a broader shift in U.S. policy toward securing domestic supplies of minerals deemed essential to national security. Antimony is listed by the U.S. Geological Survey as a critical mineral, and the United States currently relies almost entirely on imports, with China dominating global production and refining.
“While the volumes from these pilot-scale efforts are not expected to be large, the strategic value lies in developing domestic refining know-how and intellectual property,” BMO Capital Markets said in a note this week. The bank identified antimony as one of the most critical and supply-constrained materials in its latest review of defense-related minerals.
The Army’s work with Perpetua builds on an existing relationship through the Defense Ordnance Technology Consortium, which has awarded the company up to $22.4 million to advance domestic antimony processing. Together, the initiatives underscore the military’s push to establish a fully U.S.-based “ground-to-round” supply chain for key munitions materials, reducing exposure to foreign supply disruptions.
In defense applications, antimony is alloyed with lead to harden bullets and shell casings, while antimony trisulphide plays an essential role in primers and other ignition systems. For several of these uses, there are no viable substitutes, making secure access to supply a priority for the Pentagon as global geopolitical tensions persist.
“The successful demonstration of this plant will help support long-term American mineral independence and supply-chain resilience,” Perpetua Resources CEO Jon Cherry said in a statement.
Investor reaction was swift. Shares of Perpetua Resources rose 14% on Thursday to close at C$40.21 in Toronto, giving the company a market capitalization of approximately C$4.9 billion ($3.56 billion).
Perpetua began early-works construction at Stibnite in October after the project received federal support under an accelerated permitting framework. The development was fast-tracked during the Trump administration as part of a broader effort to rebuild domestic production of critical minerals used in defense systems.
Under an agreement with Battelle Energy Alliance, which manages INL, the laboratory will host, commission and operate the modular pilot plant. The facility will conduct pilot-scale testing to recover antimony and other defense-related minerals from Stibnite ore, producing material suitable for military qualification and further processing.
U.S. Representative Mike Simpson (R-Idaho) said the project highlights Idaho’s growing role in national security supply chains. “This effort demonstrates that Idaho has the potential to provide a reliable domestic source of critical minerals that are essential to meeting our country’s defense needs,” he said.
