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    McEwen’s Grey Fox PFS: mine-life, capex and return insights for gold planners

    June 9, 2026|

    Reviewed by Tom Sullivan

    McEwen’s Grey Fox PFS: mine-life, capex and return insights for gold planners

    First reported on MINING.com

    30 Second Briefing

    McEwen Mining’s pre-feasibility study for the Grey Fox underground project near Timmins, Ontario, outlines 87,000 oz/y of gold output from 2028–2041, peaking at 100,000 oz in 2029, extending the Fox Complex mine life by 15 years and feeding the existing Stock mill with 87.5% projected recovery. The $181 million initial capex project, based on 18.8 Mt at 3.28 g/t Au (nearly 2 million oz indicated, 980,000 oz in reserves), shows a post-tax NPV5 of $282 million, 25% IRR and 4.6-year payback at $3,000/oz gold. Two independent portal-accessed underground operations are planned, with construction targeted for spring 2027 and commercial production in 2029, plus a $5 million drilling programme to convert remaining resources.

    Technical Brief

    • Mining layout comprises two independent underground operations, each accessed via its own surface portal.
    • Ore from Grey Fox will be truck-hauled to surface, then road-hauled to the existing Stock mill for processing.
    • Stock mill feed will be blended with material from the operating Stock mine, implying coordinated grade and throughput control.
    • All-in sustaining cost is projected at US$2,212/oz over life-of-mine, framing operating margin sensitivity to gold price.
    • Indicated resource underpinning the PFS totals 18.8 Mt at 3.28 g/t Au, nearly 2 Moz contained.
    • Proven and probable reserves of 980,000 oz represent only ~40% of Grey Fox’s total current resource inventory.
    • McEwen has allocated US$5 million for additional drilling focused on resource-to-reserve conversion and mine plan optimisation.
    • Pre-production work includes detailed engineering, long-lead procurement, and amendments to both water permit and closure plan.

    Our Take

    Recent coverage of McEwen shows strong cash inflows from the San José gold-silver mine in Argentina and rising Q1 2026 gold revenues, which likely improves the company’s capacity to fund the US$181 million initial capital at Grey Fox without relying solely on dilutive equity.

    In our database, McEwen also appears in several copper-focused pieces via McEwen Copper and the Los Azules financing push, so committing a further US$5 million drilling budget at the Grey Fox gold deposit suggests management is still prepared to allocate meaningful exploration capital to precious metals alongside its large copper growth option.

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    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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