American Tungsten’s Idaho IMA mine: drill results and restart lens for engineers
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
American Tungsten has reported its first underground drill assays from the rehabilitated D-level at the historic IMA tungsten mine in Lemhi county, Idaho, with three key intercepts including 31 ft at 0.48% WO₃ and 1.84 oz/t Ag, 11.1 ft at 1.08% WO₃ and 2.05 oz/t Ag, and 16.3 ft at 0.54% WO₃ and 1.79 oz/t Ag. Ten upward-inclined fan holes totalling about 3,800 ft have been drilled from new footwall stations on the No.5 and No.7 vein systems to support a maiden resource and restart study. The company, which acquired the former producer in 2024, is now prioritising metallurgy and mine infrastructure restoration as it evaluates a potential underground restart in a US market with no domestic tungsten output since 2015.
Technical Brief
- Underground drilling is on the rehabilitated D-level, using upward-inclined fan holes from new footwall stations.
- IMA mine previously produced nearly 200,000 metric ton units of WO₃ between 1945 and 1957.
- Historic output also included “millions of pounds” of copper and zinc plus over 1,000 oz silver.
- Ten underground holes totalling ~3,800 ft have been completed in the No.5 and No.7 vein systems.
- The current programme is the first systematic application of modern exploration methods at IMA.
- American Tungsten acquired the project in 2024 specifically targeting an underground restart scenario.
- US tungsten supply risk is acute, with China providing ~80% of global mine output and no US production since 2015.
Our Take
With China accounting for about 80% of global tungsten mine output, a revived tungsten operation in Idaho positions American Tungsten as a potential domestic supply option at a time when US policymakers are actively seeking to de-risk critical mineral chains.
The reported WO₃ grades above 1% over short underground intercepts at the IMA project site suggest this former mine could support a selective, higher-margin underground operation rather than a bulk-tonnage model, which is consistent with how many Western US tungsten veins have historically been mined.
A potential US$25.5M loan against a roughly C$129.5M market capitalisation signals that project-level financing could be material relative to American Tungsten’s equity base, giving lenders and offtakers significant leverage over development timelines and offtake terms if the Idaho asset advances.
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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