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Highlights
- Near-complete stibnite recovery recorded during rougher flotation testing, with 99.5% sulphur recovery achieved.
- High antimony recoveries were achieved from lower grade samples containing approximately 10.5% antimony.
- 3D modelling across a 1,000m by 700m (170-acre) mineralised area revealed substantial expanding scale potential at Antimony Ridge.
- Further flotation and hydrometallurgical test work is underway, targeting grade improvement from ~30% to above 50% Sb.
Resolution Minerals Ltd (ASX:RML) (OTCQB:RLMLF) has reported encouraging outcomes from ongoing metallurgical test work at the Antimony Ridge prospect within the broader Horse Heaven Project in Idaho, USA. The results highlight near-complete recovery of stibnite (antimony sulphides) during the rougher flotation stage using lower grade samples, supporting the project’s continued advancement.
High Recovery Rates from Initial Test Work
Concentrate testwork on low grade Antimony Ridge samples from rougher flotation tests conducted at IMO laboratories in Perth demonstrated high rates of antimony recovery in sulphide. The process delivered a 99.5% sulphur recovery, highlighting almost complete extraction of stibnite at this rougher concentration stage.
The test work utilised lower grade samples containing approximately 10.5% antimony. Despite this, high sulphide recoveries were maintained, suggesting that potential dilution from surrounding waste or gangue material may not significantly impact recovery rates.
These results are significant as they suggest that the rougher flotation concentration stage can virtually capture antimony sulphides.
Support for Metallurgy Test Work
The latest results provide support for the previously reported 99.38 wt.% antimony trioxide product with minimal impurities, produced using conventional pyrometallurgical volatilisation methods from the Antimony Ridge historical open pits.
3D modelling of multiple known antimony- and silver-bearing veins, including vein swarms and stockworks, across a broad area of approximately 1,000m by 700m (170 acres), has indicated considerable size and increasing scale potential at Antimony Ridge.
Ongoing Test Work and Development Plans
Further concentration stages are currently underway on Antimony Ridge samples, with cleaner flotation stages designed to process the rougher sulphide concentrate and improve grade quality. These stages aim to increase antimony grades from nearly 30% to over 50%.
Parallel test work using hydrometallurgical processing methods is also underway at ANSTO in Australia along with continued evaluation of antimony, tungsten, and gold-bearing materials.
Antimony Ridge forms part of Resolution Minerals’ broader strategy, which includes planned drilling program at the Golden Gate target, expected to commence soon.
The latest metallurgical results from Antimony Ridge demonstrate high recovery efficiency from low grade samples. With further test work underway and development activities progressing, the project continues to advance as part of a broader initiative to support the supply of critical metals, including antimony, tungsten, and gold, from Idaho in the United States.
RML shares were trading at AUD 0.06 per share at the time of writing on 6 May 2026.
