Stockhead - Red Mountain Mining moves to secure slice of US domestic antimony supply

Special Report: Red Mountain Mining is aggressively advancing its critical minerals portfolio in the US with the intention of becoming a domestic antimony supplier.

In the past six months, the company has been on the hunt for assets in Tier-1 regions in highly prospective antimony mineral districts in Montana, Utah and Idaho.

This coincides with US Government initiatives to secure domestic antimony supplies.

This is particularly important with antimony classified as a critical metal by the United States and Australian governments.

Already, Red Mountain Mining’s (ASX:RMX) Thompson Falls antimony project has returned high-grade assays up to 36.5% antimony and 0.65g/t gold.

That project is just 4km from United States Antimony Corporation’s (NYSE:UAMY) smelter – the only operating antimony smelter in the country.

Additional assay results are expected by the end of February and a comprehensive surface mapping and sampling program to fast-track the definition of the project’s resource potential, is planned to start next month.

Don’t forget Utah and Idaho

At the Utah antimony project, RMX said mapping suggested that the same type of host rocks and extensions of the large epithermal antimony mineralising system targeted by American Tungsten and Antimony (ASX:AT4) at Antimony Canyon Project (ACP) were present.

This is notable as the projects adjoin and ACP is one of the largest and highest-grade antimony projects in the US, returning rock chip results of up to 33% with an exploration target of 12.8Mt to 15.6Mt at 0.75% to 1.5% Sb, containing between 96,000t and 234,000t of metal.

Earlier this month, Grand Gulf Energy (ASX:GGE), holding the claims between AT4 and Red Mountain’s northern claims area, reported the presence of visible stibnite in samples collected from the Dry Wash antimony project.

AT4’s Northern Extension and the Dry Wash prospects are interpreted to be controlled by north-south trending faults that extend into RMX’s claims north and south of AT4’s ground.

This points to the potential for significant mineralisation along strike from ACP, including into Red Mountain’s project area.

And in Idaho, the company is confident the Yellow Pine project holds all the necessary elements for the formation of economic gold-antimony mineralisation, featuring prospective host rocks and evidence of historical workings.

What’s more, it is in close proximity to Perpetua Resources’ (NASDAQ:PPTA) Stibnite project, at which mine construction has started based on a proven and probable reserve of 4.8Moz gold and 67,100t antimony.

USGS geology of the area encompassing Red Mountain’s Thompson Falls antimony project and UAMY’s Thompson Falls smelter and Stibnite Hill antimony mine. Source: RMX.

Western countries fund domestic supply

The Australian Government recently set aside $1.2 billion to establish a Critical Minerals Strategic Reserve, targeting antimony and rare earth elements, which is set to be operational by the second half of 2026.

In the US, the Export-Import Bank of the United States (EXIM) approved a Direct Loan of up to US$10b for Project Vault, a US initiative that aims to strengthen America’s critical minerals sector and establish a domestic strategic reserve by shielding domestic manufacturers from supply shocks, and funding expansion of US production and processing of critical raw materials.

“This and other positive signals from the US Government have driven strong interest in exploration and development projects for antimony, with US Antimony Corporation, Perpetua Resources and other players moving rapidly to increase the country’s domestic smelter and processing capacity and seeking to secure new ore supply to meet an anticipated surge in domestic US demand,” RMX said.

Looking forward, the company is well positioned to advance its US and Australian critical minerals portfolio with the warm tailwind of an unprecedented shortage of Western antimony supply and growing US and Australian government demand for critical strategic commodities.