Red Mountain Reports Up to 36.5% Antimony and 1.12 g/t Gold at Thompson Falls

Outstanding Assay Results from Historical Eastern Star Mine

Red Mountain Mining Ltd (ASX: RMX) has announced a series of impressive assay results from its Thompson Falls Antimony Project, situated on the Montana-Idaho border. Sampling from the historical Eastern Star Silver-Lead mine has revealed consistently high-grade antimony values, with assays reaching as high as 36.5% antimony (Sb) and gold grades up to 1.12 grams per tonne (g/t). Notably, a stibnite-rich rock sample returned a spot pXRF reading of 47.3% Sb, underscoring the exceptional mineralisation present.

These results highlight the project's potential as a significant source of critical minerals, particularly antimony, a metal vital for flame retardants, batteries, and other industrial applications. The presence of anomalous gold further enhances the project's economic appeal.

Strategic Location Near US Antimony Smelter

The Thompson Falls project is strategically located just 4.2 kilometres from the United States Antimony Corporation’s smelter in Montana, the only operating antimony smelter in the US. This proximity offers potential logistical advantages and synergies for future development. The project area encompasses multiple historical underground mines and pits, with mineralisation hosted in fault-controlled siderite-quartz-sulfide veins typical of the prolific Coeur d’Alene mineral district.

The Coeur d’Alene district is renowned for its polymetallic vein deposits, historically producing vast quantities of silver, lead, zinc, gold, copper, and antimony. Red Mountain’s findings suggest that Thompson Falls shares this rich mineral endowment, positioning it as a promising exploration target within a globally significant mining belt.

Advancing Exploration and Permitting Efforts

Red Mountain is accelerating its exploration program with plans for comprehensive surface mapping and sampling to better define the resource potential. The company has bolstered its US technical team with dedicated drill-permitting expertise, aiming to fast-track approvals and prepare for drilling campaigns. Additional assay results from recent sampling campaigns are expected shortly, which may further inform exploration strategies.

While no drilling has yet been conducted, the company’s methodical approach to exploration, combined with its strong assay results, lays a solid foundation for advancing the project toward resource definition.

Broader Critical Minerals Portfolio

Thompson Falls is part of Red Mountain’s broader US and Australian critical minerals portfolio, which includes the Armidale Antimony-Gold Project in New South Wales and the Utah Antimony Project. The company is focused on delivering reliable, high-quality sources of critical minerals to support strategic supply chains in the US and Western countries.

With the global demand for antimony and other critical minerals rising, Red Mountain’s exploration success at Thompson Falls could position it as a key player in securing domestic supply of these essential commodities.