USAC Antimony Expansion Targets July Start for US Defense Stockpile Supply

USAC Antimony

USAC antimony expansion at Thompson Falls in Montana is expected to be fully online by mid-July, strengthening US domestic supply of a critical defense metal. The company has started commissioning the smelter expansion and plans to bring operations online in phases.

USAC antimony expansion will add capacity at a time when Washington is trying to secure antimony ingots for the national defense stockpile. Antimony is used in ammunition, flame retardants, alloys and other defense-related applications.

USAC antimony expansion depends on the arrival of furnace parts expected in the last week of May. The company plans to start one to two furnaces each week until all nine furnaces are operating around mid-July.

By the end of July, US Antimony expects the expansion to produce at nearly 80% of its 230 t/month capacity. The company then plans to temporarily shut its older 75 t/month plant for four to eight weeks for maintenance and emissions upgrades.

Montana Capacity Supports Fixed-Price DLA Contract

The Thompson Falls expansion is directly tied to US Antimony’s five-year fixed-price contract with the Defense Logistics Agency. The contract covers 6.7mn lb, or 3,039t, of antimony ingots for the national defense stockpile and is worth up to $245mn.

USAC has received $12mn in DLA sales orders to date. It has also received the first two delivery notices for finished antimony ingots to the Department of Defense.

The federal contract will become a major revenue driver. USAC expects $75mn-95mn of its estimated $125mn revenue in 2026 to come from shipments to the US government.

That structure makes the Montana expansion strategically important. The project is not only a capacity increase; it is part of a government-backed supply chain for a material with limited domestic production.

USAC’s antimony inventories also increased sharply. Inventories reached $21.7mn at the end of the first quarter, up from $12mn at the end of 2025.

However, execution has not been smooth. The expansion was initially expected to be completed in January but was delayed by supplier and third-party issues involving concrete pads, building construction and heat exchangers.

Federal Funding Pushes US Antimony Beyond Thompson Falls

The Department of Defense awarded USAC $27mn in Defense Production Act Title III funds in February to expand antimony production and refining capacity in Montana and Alaska. The company received $12.8mn of that grant in April.

This funding shows that US antimony supply is now a defense industrial priority. China’s dominant role in antimony processing has made domestic and allied capacity more strategically valuable.

USAC is also pursuing a larger hydrometallurgical processing project in Idaho with Canadian miner Americas Gold and Silver. The joint venture was established in February.

The partners expect to complete construction of the Idaho facility in 2028. The project is targeting capacity of up to 1,000 t/month of 99.9% pure antimony.

USAC has applied for more than $274mn in federal grants across several projects. These include the hydromet facility and tungsten exploration at the Fostung site in Canada.

The company’s financial results still show the strain of expansion. USAC reported an $11.3mn first-quarter loss, compared with a $0.5mn profit a year earlier, while revenue fell by 3% to $6.8mn.

The near-term challenge is therefore operational execution. USAC must bring the Montana furnaces online, meet emissions requirements, deliver to the DLA and convert federal support into reliable production.

The Metalnomist Commentary

USAC’s Montana expansion shows how the US is trying to rebuild antimony capacity through defense contracts, stockpiles and public funding. The strategic risk is execution: domestic supply security depends on furnaces actually running, not only grants and offtake contracts.