Locksley Resources cracks code to high grade antimony concentrate in US tests
- James Pearson
- Oct 8, 2025
- 3 min read
ASX-listed Locksley Resources (ASX: LKY) has made a big step towards creating a domestic source of antimony in the United States by churning out a high-grade 68.1 per cent concentrate from simple flotation tests on samples pulled from its Desert antimony prospect.
The prospect is part of the company’s larger Mojave critical metals and rare earth project in California.
The standout result, which nudged 95 per cent of what the company described as the theoretical maximum 71.68 per cent achievable, came from just two rounds of preliminary rougher, regrind and cleaner flotation tests.
It easily surpasses the industry’s minimum sales specification of 55 per cent, highlighting the ore’s exceptional purity and suggesting minimal flowsheet tweaking will be needed to ramp up both grade and recovery
Locksley’s metallurgical consultants, Independent Metallurgical Operations and Base Metallurgical Laboratories, ran the test work which makes up part of an ongoing program on surface samples collected from the Desert antimony project.
Additional metallurgical tests were run on its basic flotation products, including regrinding and a cleaner flotation circuit. These extra steps delivered a big improvement resulting in the concentrate reaching the 68.1 per cent mark, compared to just over 30 per cent antimony seen in most of the earlier tests.
The flotation cleaning process also involves recycling the tails and with rougher stage results already in hand, the company believes the recoveries could eventually climb above 80 per cent, with more regrinding and re-flotation set to capture the rest.
Locksley says its concentrate grades are better than those currently on the market, giving it a major advantage as it works towards producing a “100 per cent Made in America” antimony product.
The company’s next step is to collect a larger bulk sample from underground at the Desert antimony prospect for more detailed testing. This work will include fine-tuning the flotation process, running the gravity separation process through its paces and trialling ore sorting, all to boost efficiency.
Locksley will also make a bigger batch of concentrate to pilot the production of antimony metal ingots, oxide and trisulphide products. Some of this concentrate will go to Rice University to trial its proprietorial DeepSolv process, which is a modern solvent extraction method that offers an alternative to traditional smelting.
A key driver behind Locksley’s strategy is the urgent need for the United States to cut its reliance on Chinese antimony. The US currently has no domestic production of the metal, leaving it vulnerable to supply shocks.
That vulnerability was laid bare when China - responsible for 81 per cent of the world’s antimony supply - suddenly halted all exports 12 months ago, cutting off a critical source for countries like the US.
Antimony is classified as a critical mineral because of its essential role in strengthening alloys, hardening lead for ammunition and improving fire resistance in semiconductors and batteries.
With Washington now moving swiftly to plug the supply gap and reduce dependence on China, Locksley’s Mojave project is emerging as a strategically positioned asset that could help rebuild a secure, domestic antimony supply chain.
The Mojave project covers more than 490 claims in California’s desert and sits next to ground held by rare earths giant MP Materials. It includes the historic Desert antimony mine, which last operated in 1937.
Recent rock chip sampling by Locksley at site pulled out some high grade samples including one running at a whopping 46 per cent antimony and more than 1 kilogram per tonne silver, setting the scene for the renewed exploration focus on the prospect.
With grades pushing the limits of what’s technically achievable, recoveries on track to exceed 80 per cent, and a strategic location in the heart of America’s critical minerals push, Locksley Resources is positioning itself as a potential cornerstone in rebuilding the US antimony supply chain.
As geopolitical tailwinds strengthen and test work accelerates, the company’s Mojave project is shaping up as one to watch in the race to secure this vital metal.
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