EV Resources (ASX: EVR) has confirmed strong antimony recoveries from preliminary metallurgical testing at its Los Lirios Antimony Project in Oaxaca, Mexico, supporting a simplified processing strategy and a lower-cost development pathway.
Test work delivered total antimony recovery of 90.8% using a reagent-free, two-stage gravity circuit. The result exceeded recoveries achieved through a more complex flotation-based flowsheet, which returned 85.3%. The gravity-only approach also produced high-quality concentrates grading between 22% and 36% antimony from a composite head grade of 4.6%.
Low tailings grades of 0.37% antimony indicate limited metal loss and efficient separation. The absence of chemical reagents reduces plant complexity and environmental permitting requirements, which may shorten development timelines.
Gravity Circuit Alters Development Assumptions
The metallurgical program evaluated two processing routes on representative composite material. Direct gravity concentration emerged as the preferred option, outperforming flotation in recovery, simplicity, and operating profile.
The gravity circuit successfully recovered both oxide and sulphide antimony minerals, including stibiconite and stibnite. This is notable given that oxide material can be challenging to process using traditional flotation methods.
EV Resources said the results support a simplified plant refurbishment strategy at its nearby Tecomatlán processing facility. Engineering and refurbishment costings are now underway, with the company targeting an investment decision by year end.
Managing Director and CEO Mike Brown said the results materially improve project planning.
“The metallurgical results from Los Lirios are extremely encouraging, confirming that high recoveries above 90% can be achieved through a simple, efficient gravity circuit,” Brown said.
High-Grade Sulphide Test Highlights Upside
Separate test work on a high-grade sulphide sample from the West Pit at Lirios 2 returned antimony recovery of 99.2% using flotation. The sample had a calculated head grade of 31.2% antimony and produced a concentrate grading more than 50% antimony after regrinding and cleaning.
While not part of the initial production plan, the result highlights upside potential as drilling progresses and deeper sulphide-dominant material becomes available.
Flotation studies will continue in parallel but are not required for the initial production scenario, according to the company.
A gravity-only processing route lowers capital intensity and technical risk. For EV Resources, this improves the likelihood of restarting Los Lirios as a near-term producer while advancing its strategy to supply antimony into North American markets.
