EV Resources has produced a 68.3% antimony concentrate from preliminary bench-scale testing of material from the Vinatas operation in Mexico. The results support Tecomatlán as a potential regional processing hub, but the proposed ore supply remains non-binding and plant-scale performance is untested.
- 78.6% peak antimony recovery through conventional flotation
- 68.3% Sb concentrate produced after gravity upgrading
- Falcon concentration reduced final tailings grade to 2.17% Sb
- Vinatas could potentially supply about 80 tonnes per month
- No binding supply agreement or Vinatas resource estimate yet
Vinatas Testwork Supports Tecomatlán Processing Model
EV Resources Ltd (ASX:EVR) has strengthened the technical case for its Tecomatlán processing strategy, reporting antimony recoveries of up to 78.6% from material sourced at the third-party Vinatas operation in Mexico. A subsequent gravity-cleaning step produced a 68.3% stibnite concentrate containing just 4.36% silica, giving EVR a potentially workable route for treating another regional feedstock.
The results came from preliminary laboratory testing rather than plant operations. Independent laboratory Metalurgia y Equipos tested stockpile material using conventional bulk flotation, gravity concentration and Falcon centrifugal recovery. EVR says the preferred route involves grinding to about 87% passing 200 mesh, flotation using a PAX and lead nitrate reagent scheme, gravity cleaning of the flotation concentrate, and centrifugal treatment of residual fine-grained stibnite in the flotation tailings.
Repeat Flotation Results and Higher-Grade Concentrate
The first flotation test returned a 58.82% antimony concentrate at 78.6% cumulative recovery from material with a calculated head grade of 13.8% Sb. A second test produced a lower-grade bulk concentrate of 47.4% Sb, but still achieved 75.8% recovery from material with a calculated head grade of 12.0% Sb. EVR describes the broadly similar recoveries as preliminary evidence that the material responded consistently under comparable conditions.
Gravity upgrading materially improved the second flotation concentrate. A Wilfley shaking table lifted the product to 68.3% Sb, while the table tailings still graded 38.0% Sb, leaving scope for recirculation or additional treatment. Separate Falcon testing also recovered fine stibnite from flotation tailings, with one three-pass sequence reducing final tailings from 6.14% Sb to 2.17% Sb.
Potential Supply Adds Another Regional Feedstock
Vinatas is covered by a non-binding memorandum of understanding signed in May 2026. The operation has previously sold run-of-mine antimony ore to a facility in San Luis Potosí, roughly 500 kilometres away by straight-line distance, while Tecomatlán is about 170 kilometres from Vinatas. EVR says Vinatas has indicated potential supply of approximately 80 tonnes a month, either as lower-grade mineralised material of about 5% to 29.9% Sb or higher-grade direct-shipping ore above 30% Sb.
That opportunity remains conditional. No binding ore supply agreement has been executed, and any deliveries would be expected only after Tecomatlán is completed and commissioned. EVR also has no ownership interest in Vinatas and has not estimated a Mineral Resource or Ore Reserve for the operation.
Bench-Scale Evidence Still Needs Validation
The principal qualification is the sample base: the testing used random grab samples from third-party stockpiles, including a 50-kilogram medium-grade sample sent to the laboratory. The company cautions that the results may not represent future deliveries or plant-scale operations. A third test using a different collector and finer grind performed less well, returning 44.0% flotation recovery, which is why EVR has nominated the Test 2 conditions as its preliminary preferred flowsheet.
Further confirmatory and variability testing is planned, alongside work to optimise intermediate-product recirculation and tailings recovery. The next meaningful test for the regional-hub thesis will be whether Tecomatlán can translate these encouraging laboratory numbers into a marketable concentrate under continuous operating conditions, while securing enough binding feedstock to keep the plant supplied.
Bottom Line?
The metallurgy is encouraging, but the investment case still hinges on scale-up results, Tecomatlán commissioning and conversion of Vinatas from a non-binding opportunity into contracted supply.
Questions in the middle?
- Will confirmatory and variability testing reproduce the 68.3% Sb concentrate and high recovery across broader Vinatas material?
- Can Tecomatlán sustain the proposed flotation, gravity and centrifugal flowsheet at plant scale?
- Will EVR secure a binding Vinatas ore agreement, and will the proposed 80 tonnes per month be sufficient for meaningful plant utilisation?