Red Mountain Mining (ASX: RMX) has strengthened its US critical minerals portfolio with the acquisition of the Thompson Falls antimony project in Idaho, comprising three historical underground mines and an open pit.
The project is located on the Montana-Idaho border adjacent to US Antimony Corporation’s (USAC) Thompson Falls smelter—America’s only operating antimony smelter, considered crucial to the nation’s critical minerals supply chain.
It sits within the same host stratigraphy and USAC’s Stibnite Hill mine, the country’s second-largest stibnite vein deposit that was restarted in last year in response to severe domestic supply shortages.
Red Mountain’s acquisition has created a unique Western asset base that will position the company to benefit from US and Australian government support as both nations seek to secure supply.
High-Grade Antimony And Gold
Initial assays from Red Mountain’s first-pass exploration at the Eastern Star underground mine returned best results of 36.5% antimony and 0.48 grams per tonne gold, 21% antimony and 0.65g/t gold, and 13.7% antimony and 0.14g/t gold, with elevated arsenic also recorded.
The company said the wide variety of listed metals for the three mines within the project area suggest that Thompson Falls has potential to also host the silver-rich polymetallic vein mineralisation typical of Idaho’s rich Coeur d’Alene mineral district immediately west of Red Mountain’s claims.
The district accounted for 18% of a total 1.25 billion ounces US accumulated silver production between 1884 and 2020 along with 7.8Mt lead, 3Mt zinc, 1.1Moz gold, 191,000t copper and 160,000t antimony.
Further Reconnaissance Work Planned
Red Mountain paid $158,000 to secure the Thompson Falls claims, liaising with Bureau of Land Management offices in both Idaho and Montana.
The company has planned further reconnaissance exploration and sampling over the project area to locate additional undocumented historical mine workings and potential mineralised exposures.
It also plans to inspect and sample the Thompson Falls underground mines to better understand the nature of mineralisation prior to finalising drill targets.
The US Government launched a $12 billion strategic minerals stockpile initiative this week, aimed at securing critical mineral supply chains.
