Fortuna’s US$1B Diamba Sud gold project: capex, returns and schedule for mine planners
Reviewed by Joe Ashwell

First reported on MINING.com
30 Second Briefing
Fortuna Mining’s Diamba Sud open pit gold project in eastern Senegal now carries a post-tax NPV (5%) of US$1 billion, a 9.4‑year mine life and probable reserves of 20.5 Mt at 1.75 g/t for 1.1 Moz, based on a US$3,500/oz gold price. The feasibility study lifts total forecast production 25% to 1 Moz but raises initial capex 40% to US$398 million and all‑in sustaining costs to US$1,332/oz, cutting IRR to 60%. Early works, including an access road and camp expansion budgeted at US$73 million, could lead to full construction in Q4 2026 and first gold by Q2 2028.
Technical Brief
- Feasibility study assumes a base case gold price of US$3,500/oz, up from US$2,750/oz in the PEA.
- Analyst Kevin O’Halloran now assigns Diamba Sud a net asset value of US$896 million, up 12%.
- Total forecast gold output is 25% higher than the PEA, at 1 Moz over the mine life.
- Internal rate of return has dropped by 12 percentage points, now reported at 60% post-tax.
- Early works budget of US$73 million covers access road construction and expansion of the accommodation camp.
- Site lies ~600 km east of Dakar in the Kenieba-Koudougou inlier, near other large gold deposits.
- Fortuna acquired Diamba Sud in 2023 via its purchase of Africa-focused explorer Chesser Resources.
- Séguéla mine expansion is forecast to lift that operation’s annual output 40% to 214,000 oz by 2029, framing regional processing and logistics synergies.
Our Take
Fortuna Mining’s push at Diamba Sud and the Séguéla mine mirrors the 2025-12-15 piece in our database that flagged a strategic pivot to West Africa to rebuild roughly 500,000 oz/y of gold output, suggesting Diamba Sud is being sized as part of a multi-asset regional platform rather than a standalone bet on Senegal.
With Diamba Sud’s post-tax NPV of about US$1 billion against a market capitalisation of roughly C$3.5 billion, Fortuna is allocating a large share of its equity value to a single Senegal gold asset, which typically increases investor scrutiny on execution risk and permitting timelines in eastern Senegal and the Kenieba-Koudougou inlier.
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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