Troilus $3.2B copper-gold NPV: capex, schedule and risk notes for mine planners
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
Troilus Mining’s updated technical report for its Quebec copper-gold project triples after-tax NPV to $3.2 billion, with a 22% IRR, 3.6-year payback, 26-year mine life and initial capex of about $1.43 billion, based on 478 million tonnes of reserves grading 0.44 g/t gold and 0.05% copper. The plan envisages a 50,000‑tonne‑per‑day open pit starting construction in 2027, first ore in September 2029 and commercial production in March 2030, with life-of-mine operating costs of $19.21 per tonne processed. Existing infrastructure includes a 50‑MW substation, 60 km of high‑voltage lines and a permitted tailings facility, materially reducing greenfield development risk.
Technical Brief
- Base-case economics assume long-term prices of US$3,600/oz Au, US$5/lb Cu and US$50/oz Ag.
- Updated technical report builds on a May 2024 feasibility that had US$884.5M NPV and 14% IRR.
- Reserve increase to 478 Mt is about 26% higher than the 2024 feasibility mine plan basis.
- Current reserve contains 6.7 Moz Au, 568 Mlb Cu and 14.2 Moz Ag in situ.
- Life-of-mine payable output totals 5.63 Moz Au, 472 Mlb Cu and 10.88 Moz Ag.
- During active mining, average annual payable production is ~251 koz Au, 20.1 Mlb Cu and 466 koz Ag.
- About 95,000 engineering hours underpin the updated design, providing a more advanced project definition.
- A 40,000 m drilling campaign on the 435 km² land package targets pit optimisation and resource conversion.
- Existing site infrastructure includes all-weather road access, 50 MW substation, >60 km HV lines and permitted TSF.
Our Take
Quebec’s decision to place the Troilus gold‑copper asset into its Filon accelerated permitting stream (27 July 2026 item) materially de-risks the path to the 2029 first‑ore target, which is often a key hurdle for financing large Canadian critical‑minerals projects.
In our database of 1,278 mining stories, few copper‑gold projects in North America combine a 20+‑year mine life with such low reserve grades as Troilus while still achieving a double‑digit IRR, which suggests the Quebec power and infrastructure context is playing a significant role in keeping operating costs competitive.
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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