Perpetua’s $1.3B Stibnite build: approvals, capex and schedule lens for mine planners
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
A US federal court has upheld key environmental approvals for Perpetua Resources’ US$1.3‑billion Stibnite gold‑antimony project in Idaho, allowing early works to continue while an appeal proceeds and a final investment decision is targeted for this year. Stibnite is designed to produce about 463,000 oz. of gold annually in its first four years and hosts 43.5 million indicated tonnes grading 1.07 g/t Au and 0.07% Sb, backed by a US$2.9‑billion EXIM loan and Department of Defense support for domestic antimony supply. Current activity includes fabrication of two autoclaves in Europe, completion of grading and utilities for the permanent camp, and a 10,000‑metre, four‑rig drill programme chasing additional gold‑antimony‑tungsten resources around Yellow Pine, Huckleberry and Hangar Flats.
Technical Brief
- Court remand focuses narrowly on clarifying Incidental Take Statement monitoring and reporting, not redoing jeopardy findings.
- Perpetua held US$574 million cash at Q2 end, funding substantial pre‑FID works ahead of EXIM drawdown.
- Third‑quarter budget is US$177 million: US$131 million detailed engineering, US$27 million field/early construction, US$7 million exploration.
- Site establishment includes temporary worker housing, ~50% of permanent units delivered, and camp grading and utilities completed.
- Initial earthworks and civils have started on the administrative pad and along the Burntlog Route access corridor.
- A minimum 10,000 m drilling campaign with four rigs has completed ~5,800 m, with assays pending.
Our Take
With 3.1Moz of gold and nearly 100Mlb of antimony resources outside current reserves, the Clark Tunnel, Yellow Pine, Hangar Flats and Huckleberry zones give Perpetua unusual optionality to extend mine life or stage expansions once the initial Idaho build is de-risked.
Compared with other antimony pieces in our database, including Beaver Brook in Canada remaining on care and maintenance under China Minmetals, Stibnite’s progression underscores how US policy support is favouring domestic antimony capacity while some non-US primary assets stay idle.
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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