Perpetua Resources’ $40m US Army award: tungsten project lens for mine planners
Reviewed by Joe Ashwell
First reported on MINING.com
30 Second Briefing
Perpetua Resources has secured a 36‑month, US$40 million cost‑share award from the US Army’s Defense Ordnance Technology Consortium to evaluate tungsten concentrate production at the Stibnite gold‑antimony project in Idaho, with Perpetua matching the funding. The programme covers surface drilling to define a tungsten resource, metallurgical test work on a 550 kg sample grading 9.2% antimony and 4.2% tungsten, and design and permitting of an exploration decline beneath the Hangar Flats pit. Drilling to date has returned up to 9.8 m at 4.6% tungsten and 8.3% antimony, indicating potential high‑grade feed beneath existing gold–antimony resources.
Technical Brief
- Initial 18‑month phase budgeted at US$18 million, split equally between Perpetua and the US Army.
- Subsequent phases’ scope and cost will be gated by preceding drilling, metallurgy, engineering and permitting outcomes.
- Exploration decline is intended to access high‑grade antimony–tungsten–gold beneath the currently permitted Hangar Flats pit.
- Any work outside the existing Stibnite mine plan footprint will trigger additional regulatory review and permitting.
- Hangar Flats currently hosts ~1.37 Moz gold and >95 Mlb antimony resources not in the mine plan.
- Wider district exploration could add to 3.1 Moz indicated/inferred gold and 99.8 Mlb antimony outside reserves.
- Stibnite historically supplied ~50% of US tungsten and ~90% of US antimony demand during World War II.
- US Government critical‑minerals awards to Perpetua now total US$126 million since 2022 across antimony and tungsten.
- No commercial tungsten mining has operated in the US since 2015, leaving defence supply wholly import‑dependent.
Our Take
The high tungsten and antimony grades in the Hangar Flats and Yellow Pine area (with several intercepts above 1% W and >8% Sb) align with the US Army–INL modular pilot plant work reported in July 2026, suggesting that process flowsheets proven on antimony could be rapidly adapted to a tungsten–antimony concentrate stream from the same orebody.
Within our 1243 Mining stories, tungsten appears far less frequently than gold, so this US-based tungsten revival at the Stibnite mining district stands out as one of the few pieces where tungsten, antimony and gold are all being advanced under a single, federally supported mine plan in the United States.
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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