AT4 Starts US Antimony Production Test Ahead of Schedule

Del Sol Restart Moves Into Production Testing

American Tungsten & Antimony Limited (ASX:AT4; OTCQB: ATALF) has begun restarting the leach and electrowinning circuit at its Del Sol Hydromet Refinery in Nevada, ahead of schedule and using material from the White Spar Antimony Mine in Arizona. The campaign is designed to produce antimony flake and, later, Regulus II antimony ingot, giving AT4 its first physical demonstration of the US mine-to-metal pathway it has been promoting.

The immediate objective is not commercial production guidance. AT4 plans to collect, wash, dry, weigh and assay the flake, then conduct remelting and fire-refining work. The resulting samples are intended for qualification discussions with prospective offtakers, strategic partners, US government agencies and defence primes. No production volumes, recoveries, grades, costs or product specifications have yet been disclosed.

Physical Samples Are the Next Commercial Test

The restart is being carried out on Del Sol’s existing configuration and within its permitted feed envelope, which AT4 says allows the work to proceed without new infrastructure or lengthy permitting delays. Independent process engineering specialists are supervising the campaign alongside AT4’s technical team and site operators, while sampling will cover feed, intermediate material, tailings and final product, with third-party verification planned for retained samples.

That distinction matters for a company seeking entry into defence and industrial supply chains. AT4 says physical product is required before qualification discussions can begin, and intends to use the campaign’s operating data to assess reagent consumption, recovery, achievable flake grade and the case for a larger antimony expansion campaign. The company also plans to use its flake as feedstock for specialty products including antimony trisulphide.

The company’s US government engagement is advancing in parallel. Its US subsidiary has been selected to enter award negotiations with the Department of Energy under the Mines & Metals Capacity Expansion program for the ASCEND-Sb Project, involving a potential award of up to US$18 million. That selection is not a funding commitment, and AT4 says discussions remain ongoing.

Acquisition Caveat Remains Central

The most important qualification sits beneath the operational headline: AT4 does not yet own the Del Sol refinery or White Spar Mine. Its proposed acquisition of Nexus Metals, which holds the relevant rights, remains conditional on shareholder approval, regulatory and third-party consents, exercise of the Del Sol option and other conditions. Shareholders are due to consider the transaction on 21 September, while the agreement can be terminated if conditions are not satisfied or waived by 27 September.

Work can proceed before completion under arrangements with Nexus Metals, but AT4 explicitly says those arrangements do not give it a legal or beneficial interest in the assets. The campaign therefore offers an operational test of the proposed strategy, rather than evidence that the transaction or its eventual economics are secured.

Tungsten Work Keeps a Second Circuit in Play

AT4 is also continuing tungsten test work at Del Sol on material from Dutch Mountain, Tennessee Mountain and third-party sources. The results are intended to inform a proposed ammonium paratungstate, or APT, circuit, with Metso engaged to complete a scoping study. The next milestones are the campaign’s assay and operating data, the proposed extended antimony run, the DOE funding outcome and completion of the APT study.