Antimony Resources puts Tecomatlán plant to its first real test

Tecomatlán enters plant-scale processing

Antimony Resources Limited (ASX:ANT) has moved its Tecomatlán processing plant from commissioning into its first operating campaign, with approximately 200 tonnes of Chinantla material now being processed in Mexico. The company is targeting its first bulk antimony concentrate from the plant, subject to the results of the proof-of-concept program.

The campaign follows successful wet and dry commissioning and is designed to test the full operating sequence at plant scale. That includes concentrate production, plant operating parameters, recovery, product quality, sampling, weighing and logistics ahead of any potential commercial shipment. The earlier 200-tonne feed preparation had left assay and commissioning outcomes unresolved; those tests are now being conducted through the plant itself.

Three feed sources support the hub model

Chinantla is supplying the current campaign under a binding five-year mineral supply agreement and is located about 8km from Tecomatlán. Antimony Resources also has non-binding memorandums of understanding with the Vinatas and Coyul operations, giving the proposed processing hub more than one potential source of third-party feed.

The laboratory results are encouraging but remain preliminary. Chinantla testwork produced up to 81.1% antimony recovery and an upgraded concentrate grading up to 62.9% Sb. Vinatas testing returned up to 78.6% recovery, with gravity upgrading producing a stibnite concentrate grading 68.3% Sb. The company says Vinatas has indicated potential supply of about 80 tonnes a month, although those volumes and grades have not been verified by Antimony Resources.

Coyul results expose both promise and a processing task

New Coyul testwork produced a primary bulk concentrate grading 45.1% Sb, with 44.6% recovery into that concentrate. Adding recovery from a Falcon centrifugal concentrator lifted cumulative antimony recovery to 73.3%, while final tailings fell to 1.5% Sb.

There is a less tidy detail in the metallurgy: arsenic tends to float with the antimony, with 1.11% As reported in the bulk concentrate. Further optimisation will target arsenic rejection, recovery of antimony remaining in tailings and confirmation of the preferred reagent scheme before any scale-up. The company cautions that these are bench-scale results from third-party material, not a guarantee of future plant performance.

Assays will determine the next commercial step

Antimony Resources plans to submit representative concentrate samples for independent assay once the 200-tonne campaign is complete. Those results are expected to establish the concentrate’s grade, recovery and impurity profile, and will inform whether a larger or potentially continuous processing program is justified.

The commercial question is particularly important because the company has previously reported a material going-concern warning alongside a A$7.0 million FY2026 loss and A$355,087 of year-end cash. Antimony Resources says concentrate sales could provide internally generated cash flow, but there is no certainty that the campaign will produce material meeting customer specifications or that any concentrate will be sold. The immediate test is whether Tecomatlán can turn promising laboratory work into independently verified, repeatable and commercially acceptable output.