Perpetua’s $2.7bn EXIM funding: Stibnite gold‑antimony capex and returns for engineers
Reviewed by Joe Ashwell
First reported on MINING.com
30 Second Briefing
Perpetua Resources has entered the final approval stage for a proposed US EXIM $2.7 billion financing package, including a $2.2 billion direct loan, to cover the estimated $2.58 billion initial capex for its Stibnite gold‑antimony project in central Idaho, with a board vote expected shortly after a 25‑day Congressional notice. The updated technical summary outlines a 15‑year mine life producing over 4.2 million oz gold and 106.5 million lb antimony, with a base‑case after‑tax NPV5 of $3.5 billion, 23.5% IRR and 2.4‑year payback at $3,250/oz gold.
Technical Brief
- US EXIM package comprises a $2.2 billion direct loan plus capitalised interest and fees.
- Perpetua reports year-end cash on hand of $714 million to complement EXIM funding.
- EXIM has issued a 25‑day Congressional notice, after which its board will vote.
- Basic engineering for Stibnite was completed in 2025 and underpins the updated technical summary.
- Initial capex has increased by over $300 million relative to the 2025 cost update.
- Stibnite is one of few known US antimony sources and among the largest outside China’s control.
- The project entered early construction in October after securing all required federal and state permits.
- Stibnite is designated under the FAST‑41 programme, giving an expedited federal permitting framework.
- Key financial backers include JPMorgan and Agnico Eagle Mines alongside the proposed EXIM facility.
Our Take
With Beaver Brook in Canada on care and maintenance under China Minmetals, Stibnite’s antimony output in Idaho would materially shift North American supply away from Chinese-controlled primary sources, which is likely a key driver behind US EXIM’s willingness to cover essentially the full initial capex.
Earlier coverage of Perpetua’s modular pilot plant with Idaho National Laboratory and US Army-linked bodies signals that Stibnite’s antimony stream is already embedded in US defence-supply testing, so this financing effectively underwrites a pathway from pilot-scale qualification to long-term domestic offtake.
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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