American Tungsten & Antimony Ltd. (AT4) is preparing to restart operations at the Del Sol Refinery in Nevada and the White Spar antimony mine in Arizona, laying the groundwork to scale processing capacity and supply essential defence and industrial materials.
Following site visits by CEO Casper Adson, AT4 outlined plans to initiate a phased restart of the Del Sol antimony flake circuit during the September quarter using feedstock from the White Spar mine.
The operational restart and planned expansions remain subject to completing the acquisition announced on July 28.
Initial batch processing is designed to gather key operational data, de-risk the ramp-up, and generate product samples for prospective customer qualification.
Data collected will also support engineering studies and form the technical foundation for future US government funding applications, including programs under the Defense Logistics Agency.
In parallel, AT4 has issued requests for proposal (RFP) to international engineering firms to scope a major expansion at Del Sol.
The expansion covers adding higher-value production circuits for Regulus II antimony metal, antimony trisulphide, sodium antimonate, and ammonium paratungstate (APT), a critical tungsten derivative.
The company has already held a pre-application meeting with the Nevada Division of Environmental Protection (NDEP) to progress approvals.
AT4 aims to expand permitted processing throughput at the 40-acre site from 18,500 short tonnes per year to approximately 100,000 short tonnes annually, alongside securing separate permits for tungsten refining.
At the White Spar mine, AT4 plans to conduct metallurgical test work, extract a bulk sample for processing at Del Sol, and execute an expanded exploration program ahead of maiden drilling.
Subject to completion, the combination aims to build an integrated US mine-to-market supply chain for tungsten and antimony, addressing growing domestic demand for conflict-free critical minerals.
