US Antimony’s Fostung tungsten resource: project economics and mine design lens
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
US Antimony has reported an SRK Consulting–prepared inferred resource of 14.62 million tonnes at 0.17% WO₃ (53.6 million lb contained) at its Fostung tungsten project, 70 km west of Sudbury, replacing a previous 12.4 million tonnes at 0.213% estimate. The company plans an initial open-pit operation leveraging existing infrastructure, followed by underground mining, and has applied for US Defense Production Act Title III funding to accelerate development. If built, Fostung could be the first tungsten ore source in the US or Canada since 2016, in a market where WO₃ prices have nearly tripled to about $1,890/t.
Technical Brief
- At US$1,890/t WO₃, in-situ metal value is estimated at ~US$4.6 billion before costs.
- Development concept is staged: initial open pit using existing regional infrastructure, then transition to underground mining.
- Next work programme prioritises step-out drilling, bulk sampling and metallurgical testwork to upgrade resource confidence.
- US Antimony operates a Montana smelter rated at 5 million lb antimony per year, giving downstream processing experience.
- China currently controls roughly 80–85% of global tungsten processing capacity, framing Fostung’s strategic positioning.
Our Take
With WO3 compound prices having tripled over the past year and China controlling roughly 80–85% of global tungsten processing capacity, a Canadian asset like Fostung in Ontario gives United States Antimony leverage in North American critical minerals policy discussions, especially around supply chain security.
The inferred 53.6 million lb WO3 at the Fostung deposit, acquired for US$5 million plus a 0.5% royalty, implies a very low in‑situ cost of entry compared with other critical‑mineral M&A in our database, which may support future financing narratives even if the grade is modest.
Other tungsten‑tagged pieces in our coverage, such as the Blue Moon Metals acquisition of the Apex gallium‑germanium mine in Utah, indicate that junior and mid‑tier players are increasingly using low‑cost acquisitions of past or non‑core assets to assemble critical‑mineral portfolios rather than greenfield exploration alone.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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