EV Resources Hits 78.6% Antimony Recovery at Vinatas Boosting Hub Model
Key Takeaways
- Independent testwork on Vinatas stibnite ore achieved cumulative antimony recovery of up to 78.6% Sb and produced a gravity-upgraded concentrate grading 68.3% Sb with only 4.36% SiO₂, confirming strong metallurgical performance using conventional processing technologies.
- Vinatas is now the second regional third-party ore source — alongside Chinantla (81.1% Sb recovery, up to 62.9% Sb concentrate) — to validate compatibility with EVR's Tecomatlán processing plant circuits.
- Vinatas is located approximately 170km from Tecomatlán, compared to the approximately 500km route to its current processing facility in San Luis Potosí, representing a significant logistics cost advantage for future supply.
- Vinatas has indicated it can supply approximately 80 tonnes per month of material, though any supply is contingent on Tecomatlán completing commissioning and no binding ore supply agreement has yet been finalised.
- EVR's next steps include confirmatory metallurgical testing under the preferred flowsheet, advancing toward a binding supply agreement, and continuing Tecomatlán plant integration toward Proof-of-Concept operations.
Vinatas testwork delivers up to 78.6% antimony recovery for EV Resources
EV Resources (ASX: EVR) has reported positive preliminary metallurgical results from material sourced at the Vinatas antimony operation in Mexico, with testwork achieving cumulative antimony recovery of up to 78.6% Sb and the production of a high-grade 68.3% Sb concentrate through gravity upgrading. The results were completed by independent laboratory Metalurgia y Equipos and confirm that Vinatas material responds strongly to conventional flotation and gravity processing technologies already installed at EVR’s Tecomatlán Processing Plant. Vinatas is now the second regional third-party ore source, following Chinantla, to validate the company’s Tecomatlán processing hub model.
Miguel Barahona, Interim CEO
“These results are another important step in building the Tecomatlán regional processing model. Vinatas is now the second regional third-party feed source, alongside Chinantla, to demonstrate strong metallurgical performance using conventional processing technologies compatible with Tecomatlán. Achieving flotation recoveries of up to 78.6%, together with the production of a High Grade 68.3% Sb concentrate through subsequent gravity upgrading, is highly encouraging…”
Key figures from the testwork program include:
- Cumulative Sb recovery of 78.6% (Test 1) and 75.8% (Test 2), using a PAX and lead nitrate reagent scheme
- Flotation concentrate grade of 58.82% Sb (Test 1) and 47.4% Sb (Test 2)
- Gravity-upgraded concentrate grading 68.3% Sb with only 4.36% SiO₂
- Falcon centrifugal concentration reduced final tailings grade from 6.14% Sb to 2.17% Sb
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Q1 FY27 testwork results — what the numbers show
Flotation performance across three tests
The testwork program evaluated three bulk flotation tests on Vinatas stibnite ore, examining the effect of different reagent schemes and grinding conditions. Tests 1 and 2 used a conventional PAX and lead nitrate reagent scheme, which delivered the strongest results. Test 3 applied an alternative collector (Aerophine 3418A) at a finer grind, which underperformed materially, returning a cumulative flotation recovery of only 44.0% Sb.
The comparable outcomes in Tests 1 and 2 are the key investor signal here. Similar grinding conditions and reagent schemes produced similar recoveries (78.6% and 75.8% respectively), providing encouraging preliminary evidence that the metallurgical response of the Vinatas material tested is repeatable. Repeatability is what separates a promising single result from a commercially credible processing route.
Based on the testwork, a preliminary preferred processing route has been identified for the Vinatas material, comprising four steps:
- Grinding to approximately 87% passing 200 mesh
- Conventional bulk flotation using the Test 2 reagent scheme (PAX + lead nitrate)
- Gravity cleaning of flotation concentrates to produce a high-grade final concentrate
- Centrifugal concentration of flotation tailings to recover very fine-grained stibnite
Results summary table
| Variable / Parameter | Test 1 | Test 2 | Test 3 |
|---|---|---|---|
| Grinding (-200 mesh) | 26 min (87%) | 26 min (87%) | 30 min (90%) |
| Main reagent scheme | PAX + Pb(NO₃)₂ | PAX + Pb(NO₃)₂ | PAX + Aerophine 3418A + Pb(NO₃)₂ |
| Calculated head grade (Sb / SiO₂) | 13.8% / 45.4% | 12.0% / 47.9% | 13.4% / 48.0% |
| Flotation concentrate grade | 58.82% Sb | 47.4% Sb | 40.0% Sb |
| Cumulative flotation recovery | 78.6% Sb | 75.8% Sb | 44.0% Sb |
| Flotation tailings grade | 3.9% Sb | 3.6% Sb | 6.1% Sb |
| Secondary gravity stage | Not applied | Table conc.: 68.3% Sb; Falcon tailings conc.: 7.5% Sb | 3-stage Falcon on tailings: reduced from 6.14% to 2.17% Sb |
Note: Results are preliminary, laboratory bench-scale metallurgical test results only and are not a substitute for larger-scale or continuous process validation.
Why antimony metallurgy matters for investors
To understand why these results are commercially meaningful, it helps to know what the numbers actually represent. Antimony recovery refers to the percentage of total antimony in the ore that ends up captured in the final concentrate — the product that is sold. A recovery rate of 75–78% means most of the metal in the feed material is being extracted, not lost to tailings.
Concentrate grade tells you how pure that product is. Stibnite (antimony trisulfide, Sb₂S₃) is the primary antimony mineral being processed here. A concentrate grading above 65% Sb is considered high-grade and is more attractive to downstream buyers because it contains less waste material to process. The gravity upgrading step — using a Wilfley shaking table — took a 47.4% Sb flotation concentrate and lifted it to 68.3% Sb while also dropping silica (SiO₂) content to just 4.36%, a low-impurity result that matters for marketability.
For EVR, the ability to consistently produce a high-grade, low-silica concentrate from third-party feed sources is what makes the Tecomatlán hub commercially viable. The more ore sources that can demonstrate strong metallurgical performance using Tecomatlán’s existing circuits, the stronger the case for the plant as a regional processing centre.
Tecomatlán as a flexible regional processing hub
Two ore sources, one processing plant
Vinatas is now the second regional source to confirm strong metallurgical performance compatible with Tecomatlán’s installed processing circuits, following the previously reported results from Chinantla. Placed side by side, the two results are closely matched:
The Chinantla metallurgical results reported an 81.1% Sb flotation recovery and a concentrate grading up to 62.9% Sb, figures that now sit alongside the Vinatas data as the two primary reference points for Tecomatlán’s regional processing credibility.
- Chinantla: 81.1% Sb recovery via bulk flotation; concentrate grading up to 62.9% Sb
- Vinatas: 78.6% Sb recovery via bulk flotation; gravity-upgraded concentrate grading 68.3% Sb
The preliminary preferred processing routes for the two sources differ in how flotation and gravity stages are combined — but crucially, both use conventional technologies already installed at Tecomatlán. As Barahona noted in the announcement, different regional ore sources may require different combinations of the plant’s flotation and gravity circuits, and that flexibility is precisely what EVR has built into Tecomatlán’s configuration.
The Vinatas supply opportunity
Beyond the metallurgy, Vinatas represents a practical near-term feedstock option. Key logistics details from the announcement include:
- Vinatas is located approximately 170km (straight-line) from Tecomatlán, significantly closer than the existing approximately 500km route to its current processing facility in San Luis Potosí
- The operation has an established history of antimony production and sales
- Vinatas has advised it is able to supply approximately 80 tonnes per month of material
- Two material options are available: lower-grade mineralised material (approximately 5–29.9% Sb) or higher-grade direct-shipping ore (greater than 30% Sb), depending on market conditions and mining schedules
- Material could initially be supplied as-mined, without requiring significant upfront processing infrastructure at the mine site
- Vinatas is included under the non-binding MOU signed in May 2026
- EVR intends to evaluate progressing discussions toward a potential binding ore supply agreement; no binding agreement has yet been finalised
Any future ore supply to Tecomatlán would be expected to commence following completion and commissioning of the processing plant.
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Next steps and forward plan
EVR has outlined four actions it intends to pursue following these results:
- Review results with the Vinatas project owners and evaluate opportunities for confirmatory metallurgical testing under the preferred operating conditions and integrated flowsheet, to further validate concentrate grade, overall recovery, and operating parameters
- Evaluate potential expanded future supply discussions, which may include advancing toward a binding ore supply agreement aligned with the arrangement being pursued for Chinantla, with any supply expected to commence following completion and commissioning of the Tecomatlán plant
- Continue Tecomatlán plant integration toward Proof-of-Concept operations, targeting production of a marketable antimony concentrate from regional third-party ore
- Evaluate optimisation opportunities including treatment and recirculation of intermediate products and flotation tailings to further improve overall antimony recovery
These steps sit within EVR’s broader North American antimony strategy, which combines the Tecomatlán processing hub and regional feedstock development in Mexico with the Los Lirios Antimony Project (approximately 50km from Tecomatlán) and its 100%-owned Dollar and Milton assets in Nevada. The company is targeting an integrated North American antimony platform, though the pace and sequencing of those broader objectives remain subject to operational progress and external conditions.
Ready to Explore EV Resources’ Tecomatlán Processing Hub Strategy?
Metallurgical testwork at Vinatas has delivered up to 78.6% antimony recovery and a high-grade 68.3% Sb concentrate, reinforcing the commercial case for EVR’s Tecomatlán plant as a regional processing centre for third-party ore. With Vinatas now joining Chinantla as a second validated feed source, the hub model is gaining meaningful technical credibility.
To dig deeper into EVR’s antimony strategy and the full Tecomatlán opportunity, explore the EV Resources project profile on Discovery Alert for further details on the company’s North American antimony platform.