American Tungsten & Antimony has commissioned Metso Finland to conduct a concept-level study for expanding ammonium paratungstate production at its Nevada Del Sol Refinery, aiming to bolster US domestic tungsten supply amid national security concerns.
- Metso appointed for FEL1 Concept Study on APT circuit
- Phase 1 design targets 2,500 tpa APT with modular Phase 2 expansion
- Study focuses on brownfield integration to reduce capital and timeline
- CEO Adson engages US government including White House meetings
- Study outputs to support critical minerals funding applications
Strategic Move to Rebuild US Tungsten Supply Chain
American Tungsten & Antimony Limited (ASX:AT4) is advancing plans to establish a domestic tungsten conversion capability by commissioning a FEL1 Concept Study for an ammonium paratungstate (APT) production circuit at its Del Sol Refinery in Nevada. The study, awarded to Finnish engineering giant Metso Finland Oy, aims to design a Phase 1 circuit with a capacity of 2,500 tonnes per annum of APT, with a potential modular expansion to 5,000 tonnes per annum.
This initiative comes amid growing US government emphasis on securing critical mineral supply chains for national security and advanced manufacturing. Tungsten, designated a critical mineral, currently relies heavily on offshore sources controlled by geopolitical competitors. AT4’s move to integrate tungsten processing domestically aligns with Executive Order 14415, which tightens sourcing requirements for defence contractors starting January 2027.
Brownfield Approach to Cut Costs and Timelines
Rather than building a standalone greenfield plant, the study will assess incorporating the APT circuit within the existing hydrometallurgical infrastructure of the permitted Del Sol Refinery. This brownfield approach is expected to materially reduce capital expenditure and expedite project timelines, critical factors given the strategic urgency.
Metso’s scope covers feed characterisation, process route selection including impurity and molybdenum removal, crystallisation, and solvent extraction where applicable. Deliverables will include a conceptual flowsheet, preliminary mass balance, equipment lists, and AACE Class 5 capital and operating cost estimates. These cost estimates, while preliminary with a wide accuracy range, will underpin future funding applications to US federal critical minerals programs.
Metso’s Expertise to Inform Next Development Phase
Metso brings extensive hydrometallurgical process development experience, including autoclave leaching and solvent extraction, supported by its research facilities in Finland. The company was selected from five international engineering proposals based on its technical team’s tungsten plant commissioning background and in-house flowsheet modelling capabilities.
AT4 Executive Chairman Timothy Morrison emphasised that the study’s outputs will be prepared to a standard suitable for review by government agencies, potential offtake partners, and funding bodies. This positions the Del Sol Refinery as a potential multi-commodity sovereign metals hub, advancing US critical minerals independence alongside the company’s antimony operations.
Active Government Engagement and Funding Pursuit
CEO Casper Adson has initiated a series of meetings in Washington, D.C., including at the White House, engaging with US government agencies to secure grant and funding support. These discussions build on progress with the Department of Energy’s Mines & Metals Capacity Expansion program, where AT4 is negotiating awards for its ASCEND-Sb Project.
Adson highlighted the national interest in rebuilding tungsten conversion capabilities on American soil, noting that Del Sol’s existing permitted footprint offers a faster path to production than greenfield alternatives. He has extended his Washington visit to deepen engagement with stakeholders, signalling the company’s commitment to aligning its technical development with US strategic priorities.
Study at Early Stage with Conditional Acquisition
It is important to note the study has not commenced and remains conditional on completing the acquisition of the Del Sol Refinery, announced in July 2026 but yet to close. The FEL1 Concept Study represents an early-stage engineering assessment with no guaranteed outcomes or production targets. Capital and operating cost estimates will have a broad accuracy range (minus 50% to plus 100%), suitable only for internal decision-making and funding engagement.
Advancing beyond this study will require further test work, a Prefeasibility Study, permitting, and securing funding. The proposed design capacities are study parameters, not production forecasts, reflecting the exploratory nature of this phase.
Bottom Line?
AT4’s commissioning of Metso for a concept-level tungsten APT study marks a critical early step in establishing a US-based tungsten supply chain, but progress hinges on acquisition completion, study outcomes, and government funding alignment.
Questions in the middle?
- Will the Del Sol acquisition complete to enable the study’s commencement?
- How will US government funding programs influence the project’s timeline and scale?
- What technical challenges might arise integrating APT processing within the existing refinery footprint?