Utah Antimony

Highlights

• Antimony prices remain trading near all-time highs due to its strategic global value.

• RMX has acquired 87 claims “Utah Antimony Project” in the prospective Antimony Mining District in Utah, USA

• Red Mountain’s Utah Antimony Project directly adjoins Trigg Minerals’ (ASX: TMG) Antimony Canyon Project (ACP) – one of the largest and highest-grade Antimony projects in the USA, with a defined conceptual Exploration Target of 12.8 to 15.6 Mt @ 0.75% to 1.5% Sb, containing between 96,000 to 234,000 tonnes of Antimony metal

• Antimony-bearing Flagstaff Formation and controlling structures outcrop within TMG’s claims and are interpreted to extend below shallow cover (less than 20m) into Red Mountain’s Project

• RMX believes the Utah Antimony Project has high potential for discovery and similar mineralisation to that observed at TMG’s Antimony Canyon Project

• Funding was achieved 100% through internal financing, with no third-party vendor shares

• Exploration activities are set to commence shortly, with RMX’s US based technical team currently assessing further opportunities to complement the Utah Antimony Project

• The Trump administration has taken urgent measures towards securing its Critical Minerals supply chains with the intention for a federal investment up to US$1b, announced in August

Antimony mineralisation in the Antimony Mining District

RMX’s claims lie immediately along strike to the north and south of Trigg Minerals’ (ASX:TMG) Antimony Canyon Project (Figure 1). Trigg recently entered the district through the initial purchase of 49 mining claims (ASX: TMG Announcement 20 May 2025). ACP includes more than 30 historical mine workings surrounding both Antimony Canyon and Dry Wash Canyon, approximately 6km north of the main prospect. 

Antimony mineralisation within the Antimony Mining District is related to a north-south trending fault system interpreted to be splays of the Paunsaugunt Fault. These structures are considered to have acted as pathways for hydrothermal fluids sourced from nearby volcanic centres. Antimony is typically found in discrete veins or in stockwork zones, where numerous stibnite veins form dense networks within the host rocks that run roughly parallel to the surrounding rock layers.

At Antimony Canyon and Dry Wash Canyon, the main host unit is the Early Palaeocene Flagstaff Formation, comprising carbonate-rich fluvial sandstones and conglomerates. Recent work by Trigg Minerals  (ASX: TMG) has highlighted a brittle felsic volcaniclastic horizon within the Formation as a particularly prospective host, with mineralisation also observed across multiple rock layers. This indicates that mineralisation potentially extends both across the area and at depth. Channel sampling by TMG within and adjacent to historical workings has returned multiple assays exceeding 10% Sb, including a best result of 1.5 m @ 33.2% Sb from the Stebenite Mine at Antimony Canyon.

Antimony Canyon and Dry Wash Canyon represent two eroded windows into the Flagstaff Formation through a thin (interpreted to be mostly <20m thick), but laterally extensive blanket of alluvial and sedimentary cover. However, north-south trending faults that provide fluid conduits for antimony-rich mineralising fluids and the Flagstaff Formation host stratigraphy are interpreted to extend beneath the cover and into RMX’s tenements. Red Mountain therefore believes that the Utah Antimony Project has high potential for discovery similar mineralisation to that seen at Antimony Canyon and Dry Wash Canyon.