Facing increasing export control by the Chinese Communist Party in crucial mineral sectors, the US defense system is accelerating efforts to rebuild its supply chain. Recently, the US Army announced the initiation of a notable strategic plan – the development of mobile and modular small-scale refining plants for domestic production of military-grade antimony trisulfide.
This critical material, used in the production of bullet primers, has been out of production in the US for over half a century and has been predominantly supplied by China. With a series of export bans implemented by China from 2024 to 2025, antimony suddenly became a focus of national security and economic interests. The US military-led demonstration of the “mobile refining plant” signifies America’s attempt to restart the long-lost domestic antimony supply chain through technological innovation and cross-sector cooperation.
On December 9th, the US military announced plans to develop a series of modular small-scale refining plants for producing key minerals essential in manufacturing bullets, armor, and other types of weapons. The goal is to tap into domestic mineral resources to supplement the long-standing monopoly of special minerals by Chinese miners. Antimony ore is the first mineral to be refined under this military plan.
Antimony, a bluish-silver mineral, is commonly used in alloys to enhance durability. Antimony trisulfide, used to manufacture primers, the explosive cap at the bottom of bullets, is a crucial material for military products. However, the US has ceased production of this antimony since the 1960s, relying heavily on imports for antimony products.
To produce antimony trisulfide, the US Army has invested $30 million and spent several years developing a small-scale refining plant project. Designed by the Canadian private company Westpro Machinery, this small-scale refining plant is modular and can be transported in four shipping containers.
This type of mobile and modular refining plant can theoretically be moved like shipping containers via trucks or trains to conduct antimony refining at any location identified by the military, eliminating the need for occupying a fixed space like traditional large-scale refining plants.
Each of these small-scale refining plants can produce 7 to 10 tons of military-grade antimony trisulfide annually, although it is significantly lower than the output of commercial refining plants, it is adequate to meet the demand of the US Army in peacetime.
Mark Mezger, an ammunition procurement consultant for the US Army, told Reuters on December 9th, “We need to find a way to produce our critical minerals domestically so that we can truly monitor and control these minerals within our borders.”
“Without antimony trisulfide, you can’t make primers. Without primers, you can’t make bullets. A military without bullets is just a parade,” Mezger said.
Mezger stated, “In the event of a conflict, the army can expand processing capacity by adding modules to the small-scale refining plant to handle antimony ore from Perpetua’s mine in Idaho.”
The US Army’s small-scale antimony refining plant project is developed in partnership with the Idaho National Laboratory (INL) and antimony miner Perpetua Resources.
Perpetua Resources, based in Boise, Idaho, is a company with billionaire investor John Paulson as its largest shareholder. The Stibnite Gold Project owned by Perpetua is located in central Idaho near the town of Yellow Pine. Since the early 20th century, it has been a significant mineral producing area in the US, being the world’s largest Stibnite production area in the 1930s-1950s. During World War II, the mine provided approximately 90% of antimony and 40% of tungsten for the US military and was designated as a strategic resource zone.
This area is a mixed gold and antimony mine and is the only known antimony mine in the US, estimated to have up to 148 million pounds of antimony reserves. According to a 2023 briefing by the United States Geological Survey (USGS), the mine is expected to meet approximately 35% of the US’s antimony demand in the first six years of extraction.
Besides antimony resources, the Stibnite Gold mine is also set to become one of the highest-grade open-pit gold mines in the US. As per data from Perpetua, the site is estimated to contain around 4.8 million ounces of gold, with an estimated annual production of 450,000 ounces in the first four years.
With nearly no other economically viable antimony deposits in the US, the Stibnite Gold mine is the only antimony project recognized by the Department of Defense and the Department of Energy as a “domestic critical mineral supply strategic asset.”
After China imposed the ban on antimony exports in 2024-2025, the Stibnite Gold mine is seen as the fastest and most reliable domestic source for the US to break China’s monopoly.
Reducing the US’s dependency on critical minerals from China has become one of the Trump administration’s top priorities. In March of this year, President Trump signed an executive order authorizing the acceleration of critical mineral development projects.
On April 18, the White House announced that ten mineral development projects, including the Stibnite Gold mine in Idaho, will be included in the Federal Permitting Improvement Steering Council (FAST-41), granting them status that requires open tracking of approval progress and priority processing benefits.
Perpetua plans to mine antimony in the Stibnite Gold mine area, but they do not refine it themselves. They are actively seeking partners to complete the refining step, which is necessary.
The US Army’s pilot plant project is part of a broader collaboration between Perpetua and the US Army through the Defense Ordnance Technology Consortium (DOTC) to ensure the domestic supply of critical minerals.
In May 2025, Perpetua received an additional $6.9 million in DOTC funding, bringing its total DOTC funding to $22.4 million. This funding combines Perpetua’s antimony resources in Idaho with the world-class research capabilities of the Idaho National Laboratory to support the US Army’s goal of establishing a fully domestic “from mine to ammunition” antimony supply chain.
These small-scale refining plant facilities will be located at INL, leveraging the laboratory’s critical strategic materials and defense projects. INL’s well-trained operators and professionals will be responsible for the plant’s commissioning and operation, along with a six-month testing period. During this process, INL scientists will validate their processing methods according to military standards and ensure the entire process is “cleaner and more efficient.” If the testing is successful, the small-scale refining plants will be jointly operated by the Army and Perpetua.
If the model of small-scale antimony refining plant proves successful, Washington also plans to develop refining plants for its other minerals, including tungsten, rare earths, and boron, all considered critical minerals by the US government.
Officials have indicated that refining plants for other minerals may also be located on military bases or other government lands. Reuters first reported in March that the Trump administration is considering building metal refining plants within US military bases.
Jon Cherry, President and CEO of Perpetua, stated in a press release on December 9th, “We are honored to collaborate with the Idaho National Laboratory to further enhance America’s defense capabilities and help ensure the domestic supply of antimony trisulfide.”
He said, “This collaboration highlights Idaho’s role in national security and demonstrates our continued commitment to responsible resource development, job creation, and workforce training in Idaho. The successful demonstration of this plant will contribute to the ongoing growth of American mineral resource independence and resilience.”
The Idaho National Laboratory possesses extensive expertise in various fields, including mineral characterization, geochemical modeling, and material separation. INL’s critical materials research focuses on essential components required for energy and national security.
John Wagner, Director of INL, stated, “The ability to produce antimony trisulfide, necessary for producing ammunition and defense systems domestically, not only strengthens the resilience of the US supply chain but also enhances Idaho’s leading position in critical mineral and workforce development.”
For a long time, the US has faced significant challenges in antimony mining and processing, mostly due to high dependence on imports. Data shows that the US is highly reliant on antimony imports, with 83% dependency, of which 63% of the imported amount comes from China. In 2022, the US antimony consumption was around 27,000 tons, with 40% used in flame retardants production and 36% in military equipment manufacturing.
This excessive reliance on imports has left the US vulnerable in critical mineral supply chains. Any disruption in external supply, whether due to geopolitical conflicts or changes in supplying country policies, could have a significant impact on related industries in the US.
As the primary producer of global antimony, China accounts for about 48% of the extraction and a higher refining proportion. In 2024, the Chinese authorities gradually strengthened export controls on antimony, leading to a comprehensive ban on the US eventually. On August 14, 2024, the Chinese Ministry of Commerce announced initial control measures, implementing an export permit system for antimony ore and related products.
Christopher Ecclestone, a mining strategist at London-based Hallgarten & Company, believes that the restrictions imposed by China will put pressure on the US and European armed forces. He stated that the military use of antimony has become a key factor in controlling the industry: “Everyone needs it to make armaments, so it’s better to keep it rather than sell it.”
On December 3, the Chinese Ministry of Commerce issued another notice announcing the decision to strengthen export controls on military and dual-use items to the US, essentially denying export of bismuth, germanium, antimony, superhard materials, and other dual-use items to the US.
Entering 2025, the ban led to a surge in antimony ore imports to the US from countries like Thailand and Mexico, acting as transit points for Chinese antimony, causing antimony prices to reach $57,000 per ton at one point. This accelerated global supply chain restructuring, with the US spearheading the revival of the domestic project, Stibnite Gold mine.
At the end of October, Trump and Chinese leader Xi Jinping met in South Korea, leading to a relaxation of tensions in US-China bilateral trade. On November 9, 2025, China announced a one-year suspension of the ban but retained the permit approval system for antimony exports.
From mining companies to national laboratories, and to the US Army, the cooperation of all three parties is gradually forming a strategic mining lifeline that was overlooked in the past. Antimony is just the first step, and if this mobile modular refining technology proves viable, tungsten, rare earths, boron, and more critical minerals may also return to US domestic production through the same model.
In response to the further strengthening of export approval systems by China and the pressure of global supply chain reorganization, Washington is taking action, no longer entrusting the lifeline of its armaments to foreign countries. In the future, whether the US can truly break its dependency through this new “from mine to ammunition” chain, establish resilience, will become a key indicator in observing the US-China strategic competition.