• A 200-tonne Proof-of-Concept campaign has begun at the Tecomatlán Processing Plant, the first plant-scale processing of third-party material.
  • Preliminary laboratory work reported antimony recovery of up to 81.1 per cent for Chinantla material.
  • Two of the three feed sources rest on non-binding memoranda, and no Mineral Resource or Ore Reserve exists for any of them.

Antimony Resources Limited (ASX:ANT) has announced the start of a 200-tonne Proof-of-Concept campaign at the Tecomatlán Processing Plant in Mexico. The company describes it as the first plant-scale processing of third-party material at the facility, following the successful completion of wet and dry commissioning. The campaign aims to produce the first bulk antimony concentrate and to validate grade, recovery, impurity levels, operating parameters, and handling, sampling, weighing and logistics before any commercial shipment.

The plant and the feed

The plant has combined flotation and gravity circuits, which Antimony Resources says allows each feed to be treated according to its mineralogy. Three sources of material are described. Chinantla, about 8 kilometres from the plant, supplies the current campaign under a binding five-year Supply agreement. Vinatas, about 170 kilometres away in a straight line, is covered by a non-binding memorandum of understanding, with indicated supply of about 80 tonnes a month, either lower-grade material of about 5 to 29.9 per cent antimony or direct-shipping ore above 30 per cent. The operator provided those figures and the company says it has not verified them. Coyul, about 28 kilometres away, is covered by a non-binding memorandum signed in May 2026.

Laboratory results so far

The company also reported preliminary laboratory results from Metalurgia y Equipos. For Chinantla, recovery was up to 81.1 per cent of antimony by bulk flotation, with an upgraded concentrate grade of up to 62.9 per cent antimony. For Vinatas, flotation recovery was up to 78.6 per cent, with 75.8 per cent in a follow-up test, a flotation concentrate of 58.82 per cent antimony, and a gravity-upgraded concentrate of 68.3 per cent antimony containing 4.36 per cent silica.

For Coyul, the best of four tests used feed grading 4.20 per cent antimony. It produced a primary concentrate of 45.1 per cent antimony, with total recovery of 73.3 per cent, made up of 67.7 per cent from flotation and a further 5.6 per cent from treating tailings with a Falcon concentrator. Arsenic reported at 1.11 per cent in the bulk concentrate. The laboratory considers the 45.1 per cent concentrate marketable and recommended the flowsheet used in that test, including a cleaner stage and regrinding.

Commercial position

The announcement is about process validation rather than sales. The company says the campaign is not based on a production target or feasibility study, and there is no certainty that it will produce concentrate meeting specifications or that any concentrate will be sold. No Mineral Resource or Ore Reserve exists for Chinantla, Vinatas or Coyul, and the company holds no ownership interest in any of them. Antimony Resources says it is funded through the planned Proof-of-Concept phase.

Risks and conditions

The metallurgical results are described as preliminary and bench-scale, and the company cautions that they are not a guarantee of plant-scale or future-delivery performance. Two of the three feed sources rest on non-binding memoranda, so supply from them is not contracted. The Vinatas supply figures are unverified. Plant-scale performance may differ from the laboratory results, which is the question the campaign is designed to answer.

Next steps

The company lists several milestones. It plans to complete the 200-tonne campaign and submit representative concentrate samples for independent assay, then release concentrate grade, recovery and impurity results. It intends to evaluate a larger, potentially continuous, processing programme at Tecomatlán, progress the Vinatas memorandum towards a binding supply agreement, and finalise agreements with offtakers. It also plans to complete Coyul optimisation work, focused on arsenic rejection, antimony recovery from tailings and confirmation of the preferred flowsheet. The announcement does not give dates for these steps.

Separately, the company notes that its Los Lirios project in Mexico, about 50 kilometres from Tecomatlán, is being advanced towards a maiden JORC Mineral Resource, and that it holds the 100 per cent owned Dollar and Milton antimony Assets in Nevada.