The US Department of Defense (DoD) awarded an Ordnance Technology Initiative Agreement (OTIA) of up to US$15.5M to Perpetua Resources.

Perpetua will need to demonstrate a US domestic antimony trisulphide supply chain using ore from its Stibnite gold project. Under the OTIA, Perpetua will be reimbursed for these activities on a cost-plus fixed fee basis over a 24-month period. The estimate of up to US$15.5M is subject to adjustment based on scope, costs, budget, or other factors as the program advances.

Antimony trisulphide is mainly used for ordnance primers, tracer bullets, pyrotechnics, and for friction brakes. As such, it is a key component in military applications. The USA is dependent on imports of antimony to meet its demand. United States Antimony Corporation (USAC) operates the Thompson Falls plant in Montana as the only remaining antimony refinery in the USA, supported by mines owned and operated in Mexico. USAC installed antimony trisulphide furnaces in 2022 and at the start of 2023 to supply the DoD and Defense Logistics Agency (DLA).

Military applications, which gain the metal its criticality status in the USA, are however only a small portion of antimony’s demand. Major uses of the metal are in lead-acid batteries (largely met from recycled end-of-life feedstock) and as antimony trioxide in flame retardants and plastics (the main driver of primary mined antimony).

According to Project Blue data, antimony is and will remain in tight supply to meet global demand. Demand estimates for 2023 have been revised downwards based on a lack of feedstock availability, with the market now supply-driven. While this paints a positive picture for new mines to enter the market, the risks include by-product antimony from large gold mines able to flood the market intermittently and that the majority of the antimony smelters are in China.

The published mine plan and antimony supply from the Stibnite gold project will add crucial units to the market, though a little too late to support the current demand erosion. While reported annual volumes are significant, the life of mine is limited to support the global industry beyond the current supply concerns, so a domestic partnership may prove crucial for the project.