Gunnison Copper project nears US$2B NPV: capex, throughput and LoM notes for mine planners
Reviewed by Joe Ashwell
First reported on MINING.com
30 Second Briefing
Gunnison Copper has updated the PEA for its Gunnison project in Arizona, lifting post-tax NPV (8% discount) to US$1.95 billion at US$4.60/lb copper, with mine life extended to 21 years and post-tax IRR rising to 23% despite an 18% increase in initial capex to US$1.54 billion. The plan envisages 3.2 billion lb of copper cathode over life-of-mine, averaging 174 million lb/year for the first 15 years from an open-pit, heap leach operation using solvent extraction–electrowinning. About 83% of the US$692 million NPV uplift comes from operational changes, notably adding the Strong & Harris satellite deposit with 25 million tonnes and incorporating material sorting and optimisation.
Technical Brief
- Strong & Harris satellite deposit contributes ~25 million tonnes of additional open-pit, heap-leach feed.
- Gunnison resource (initial PEA) totals 831.6 million measured/indicated tons at 0.31% Cu (~5.1 Blb).
- Inferred resources add 79.6 million tons at 0.20% Cu for ~325 Mlb contained copper.
- Gunnison deposit lies ~2 km north of the currently producing Johnson Camp mine (JCM).
- Planned processing route mirrors JCM: heap leach with solvent extraction–electrowinning for cathode production.
- Gunnison Copper’s market capitalisation sits around C$254 million, versus project NPV in the multi‑billion‑dollar range.
Our Take
An NPV of US$1.95 billion at an 8% discount against a market valuation of about US$186 million for Excelsior Mining signals a very wide developer discount, which in our database tends to narrow only once financing and permitting milestones are clearly de‑risked on copper projects in Arizona and neighbouring states.
The assumed copper price of US$4.60/lb at Gunnison sits toward the upper end of price decks used in recent copper PEAs in our coverage, suggesting lenders and strategic investors such as Rio Tinto’s Nuton arm will scrutinise downside cases carefully, especially given the 18% uplift in initial capex.
Measured and indicated resources of 5.1 billion lb of copper at Gunnison place it among the larger single-asset copper stories in our 544 copper-tagged pieces, which typically gives operators more flexibility to phase development or bolt on satellite deposits like Strong & Harris without materially shortening mine life.
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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