- 01RMX: high-grade Sb-Au at Thompson Falls.
- 02Best: 36.5% Sb, 1.12 g/t Au; 47.3% Sb pXRF.
- 03Spring reconnaissance, more sampling, and drilling prep.
Red Mountain Mining (ASX: RMX) has delivered additional high-grade antimony and gold assay results from the historical Eastern Star Silver-Lead mine within its Thompson Falls antimony project on the Montana-Idaho border in the US.
Red Mountain’s US field team located three historical underground mines and a pit within the Thompson Falls project area, with records from the Idaho Geological Survey and Montana Bureau of Mines and Geology listing produced metals as silver-lead, antimony, and antimony-silver-copper-zinc-lead.
The company reported strong average values of 8.7% antimony and 0.37 grams per tonne gold from sampling at Eastern Star, with peak assays returning up to 36.5% antimony and 1.12g/t gold.
An exceptionally high-grade stibnite sample also returned 47.3% antimony from a spot portable X-ray fluorescence (pXRF) reading, highlighting the project’s emerging potential within a Tier-1 United States mining district.
High-Grade Results from Eastern Star
Sampling at the historical Eastern Star mine produced a series of elevated to high-grade antimony results accompanied by detectable gold across all samples collected.
New assay results received include 17.0% antimony and 1.12g/t gold, 16.4% antimony and 0.17g/t gold, 15.4% antimony and 0.32g/t gold, 11.0% antimony and 0.04g/t gold, and 10.2% antimony and 0.71g/t gold.
The highest values recorded across the overall sampling program reached 36.5% antimony and 1.12g/t gold.
A stibnite-rich rock sample returned 47.3% antimony from a spot pXRF reading, with visual logging estimating 45% stibnite across the full sample.
Geology and Mineralisation Profile
Most samples collected from Eastern Star closely resemble the quartz-stibnite veins mined at United States Antimony Corporation’s nearby Stibnite Hill deposit approximately 7 kilometres east of the project area.
The veins in the district principally comprise siderite with quartz and sulphide minerals including tetrahedrite, galena, sphalerite and chalcopyrite, and can extend along strike for more than one kilometre and to depths of up to 1.5km.
Red Mountain believes the variety of metals produced historically within the project area suggests potential for silver-rich polymetallic vein mineralisation typical of the Coeur d’Alene mineral district immediately west of its claims.
Further Reconnaissance Sampling
With the spring season commencing, Red Mountain plans to undertake further reconnaissance exploration and sampling to locate additional undocumented historical mines or mineralised exposures across the project area.
The company also intends to inspect and sample the underground mines already located to better understand the nature of mineralisation prior to designing the next stage of exploration aimed at defining resource potential.
Red Mountain has engaged specialist permitting expertise to assist with the anticipated drilling process at the Thompson Falls Antimony Project as it advances its US critical minerals portfolio.
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