Fortuna’s Diamba Sud Locks in 14 MW Power Plant for 2027

Wärtsilä has contracted to supply a 14 MW captive power plant for Fortuna Mining’s Diamba Sud gold project in Senegal, with kit due on site in March 2027 and the plant ready to run by late 2027. Announced on 27 August 2026, the deal covers five Wärtsilä 32 engine generating sets for a remote site that has no external grid connection, making this power plant the sole electricity source for what is shaping up to be one of West Africa’s next gold mines.

The contract lands at a specific moment in Diamba Sud’s development calendar. Fortuna Mining completed a positive feasibility study in June 2026, obtained its environmental decree from Senegal’s Ministry of Environment the same month, and authorised an early-works budget of US$73 million to begin de-risking the construction schedule. A mining permit application has been with regulators since February 2026. Each of those milestones matters on its own. Together, with a contracted critical-path power plant now sitting on top, they tell a more pointed story.

Here is what that story looks like in practice: the Wärtsilä order’s signal about Fortuna’s final investment decision timing, how the power architecture builds in energy cost optionality over a 9.4-year mine life, and what the adjacent US$200 million Bambadji acquisition adds to the district-scale investment case.

Inside the Wärtsilä supply contract: scope, parties, and timelines

Africa Power Services (APS), a France-based EPC contractor (engineering, procurement, and construction), placed the order with Wärtsilä on Fortuna Mining’s behalf and will be responsible for delivering the complete power plant at the remote Kédougou site.

Wärtsilä’s scope of supply covers:

• Five Wärtsilä 32 generating sets, forming the baseload generation core
• Basic engineering for the installation
• Engine-specific auxiliary units
• An engine control and monitoring system
• Advisory services across both installation and commissioning phases

The fixed calendar is what gives this contract its weight. Generating equipment is due to arrive on site in March 2027, with the full plant targeted for commissioning before the close of 2027. Those are not aspirational dates attached to a letter of intent; they are engineering-backed milestones embedded in a contracted scope of supply.

Cedric Fernandez, Managing Director at Africa Power Services, and Marc Thiriet, Energy Business Director for Africa at Wärtsilä Energy, are the named principals on the announcement. APS brings a proven portfolio in African mining power, covering continuous power supply projects for gold operations across Burkina Faso, Mali, and Senegal, and including a 12 MW thermal power station completed in 2024 for Société Nationale Industrielle et Minière (SNIM), the Mauritanian iron ore producer, at its Zouerat mining facility.

The delivery and commissioning milestones create a hard timeline. Fortuna’s broader construction schedule is now anchored to a specific operational date for power, which means the development clock at Diamba Sud is running.

Why a captive HFO microgrid, and where solar and batteries fit in

Diamba Sud sits in the Kédougou region of southeastern Senegal, with no connection to an external electricity grid. That geographic reality dictated the power architecture: a captive, islanded microgrid that the mine will depend on entirely.

The Wärtsilä 32 platform is the first component of a three-part hybrid system outlined in Fortuna’s feasibility study:

• Heavy fuel oil (HFO) generation: Contracted and now in procurement, delivering baseload power via the five Wärtsilä 32 generating sets
• Solar PV: Targeted for integration during the first year of mine operations, adding renewable generation to reduce fuel consumption
• Battery energy storage system (BESS): Planned as part of an integrated energy management system, smoothing intermittent solar output and optimising overall power delivery

This is not a default diesel installation. The Wärtsilä 32 engine is specifically designed to accommodate future renewable integration, meaning the power plant can evolve as the mine’s operational profile develops. Wärtsilä brings a deep operational history combining its generating sets with energy storage systems, spanning more than five years of integration experience across multiple projects, which underpins the hybrid configuration Fortuna has planned.

The three-part architecture at Diamba Sud reflects a broader shift toward hybrid power solutions across African mining operations, where combining HFO baseload generation with solar PV and battery storage has become a standard approach for reducing operational fuel costs over a mine’s life.

For a mine with a 9.4-year life and total development capital approaching US$400 million, the modular design matters. Fortuna is building energy cost optionality from day one: the HFO plant runs the mine at startup, and as solar and battery storage are layered in, the operating cost profile has a structural pathway to improvement. At a remote off-grid site, that kind of optionality reduces both upfront operational risk and long-run energy cost exposure.

Reading the FID signal: what this order reveals about Fortuna’s construction timeline

The Wärtsilä power contract did not arrive in isolation. It is the latest in a sequence of milestones that have accumulated since early 2026, each one narrowing the gap between study-phase planning and physical construction commitment.

Fortuna secured its environmental approval from Senegal’s Ministry of Environment in June 2026, a milestone that cleared the regulatory path for early-works spending and set the conditions under which critical-path procurement, including the power plant order, could proceed with confidence.

Read that sequence from top to bottom. Environmental approval secured. Feasibility economics confirmed. Early-works spending authorised at US$73 million. And now a contracted power plant with a March 2027 delivery window that maps directly onto a construction schedule targeting first gold in Q2 2028.

Equipment orders of this scale, with defined engineering commitments, fixed delivery windows, and commissioning advisory scopes, are not placed on a speculative basis. They are consistent with critical-path procurement programmes where the ordering party has high internal confidence that construction will proceed.

According to Fortuna’s published guidance, the company is targeting an FID on Diamba Sud within H2 2026, which is the period beginning now, with construction commencement in Q4 2026. The total development capital sits at approximately US$400 million. The convergence of environmental approval, early-works spending, and a contracted power plant means the question is no longer whether Diamba Sud will proceed. It is when the formal announcement arrives.

Bambadji acquisition adds district-scale context to the Diamba Sud power investment

On 10 August 2026, seventeen days before the Wärtsilä contract announcement, Fortuna Mining signed definitive agreements to acquire the Bambadji advanced gold exploration project in Senegal for US$200 million in cash.

Key terms of the deal:

• Vendors: Subsidiaries of Barrick Mining Corporation and IAMGOLD Corporation
• Acquisition price: US$200 million (cash)
• Land area: Approximately 190 km²
• Location: Adjacent to Diamba Sud, within the Senegal-Mali Shear Zone, one of West Africa’s most prolific gold-bearing structural corridors
• 2026 exploration budget: US$8 million approved for the remainder of the year

According to research compiled from multiple sources (though not independently confirmed by the original Wärtsilä announcement), several Bambadji drill targets sit within approximately 20 km of the planned Diamba Sud plant site. If that proximity holds through further exploration, it raises the prospect of regional resource consolidation around a single processing hub over time.

The sequencing matters. Fortuna locked in 190 km² of highly prospective adjacent ground on 10 August, then contracted a centralised power plant on 27 August. That is a company running a simultaneous resource expansion and infrastructure commitment strategy. Bambadji transforms Diamba Sud from a standalone mine development into a potential district hub, which increases the strategic value of the infrastructure being contracted now and adds a longer-term resource optionality dimension to the investment case.

The Bambadji acquisition positions Fortuna at the centre of a broader consolidation trend in the West African gold sector, where major and mid-tier producers have been securing district-scale ground packages along the Senegal-Mali Shear Zone and adjacent structural corridors.

What the power contract changes for Fortuna’s Diamba Sud investment case

The Wärtsilä order slots into a picture that has taken shape rapidly. Environmental approval is secured. Early works are funded. The Bambadji ground is locked in. And now a critical-path power plant is contracted with a fixed commissioning date.

One variable remains outstanding: the mining permit. Fortuna submitted its application in February 2026, and approval is pending as of 28 August 2026. That is now the regulatory gate between Fortuna’s current execution posture and a formal construction commitment.

The mining permit remains the single outstanding regulatory gate, with Fortuna’s application lodged since February 2026 and a decision from Senegal’s mining authorities still pending as the construction programme accelerates around it.

Three developments will move Diamba Sud to its next material milestone:

• Mining permit grant: The remaining regulatory approval that clears the path to a formal construction decision
• Formal FID announcement: Targeted for H2 2026, confirming Fortuna’s commitment to the approximately US$400 million mine build
• Construction commencement: Targeted for Q4 2026, with first gold targeted at Q2 2028

For investors tracking Fortuna’s growth pipeline, the risk profile at Diamba Sud has shifted. The remaining uncertainty is regulatory, not technical or commercial. The feasibility economics are confirmed. The power architecture is contracted. The adjacent resource base is secured. What separates Diamba Sud from a construction-stage project is a permit decision from Senegal’s mining authorities.

This article is for informational purposes only and should not be considered financial advice. Investors should conduct their own research and consult with financial professionals before making investment decisions. Forward-looking statements regarding construction timelines, production targets, and the final investment decision are based on company disclosures and are subject to change based on regulatory, market, and operational developments.