London- and Toronto-listed Endeavour Mining Corporation has completed a positive prefeasibility study (PFS) for the Assafou-Dibibango project on the Tanda-Iguela property, in Côte d’Ivoire.

The company says the PFS results meet Endeavour’s strategic targets and confirm Assafou’s potential to be a Tier 1 asset, which justifies advancing the project to the definitive feasibility study (DFS) stage.

The PFS outlines 329 000 oz/y of gold production at an all-in sustaining cost of $892/oz over first ten years, with a 15-year mine life based on maiden reserves of 4.1-million ounces.

The PFS also indicates robust project economics with an after-tax net present value of $1.53-million and internal rate of return of 28%, at a $2 000/oz gold price.

The company expects it will need to invest initial capital of $734-million based on a five-million-tonne-a-year nameplate capacity, with a similar processing plant configuration as the company’s nearby Lafigué mine.

“I am delighted with the results of this PFS, which highlight the potential for Assafou to become a Tier 1 asset for Endeavour,” says CEO Ian Cockerill.

He adds that the company has defined a large, low-cost and long-life project capable of producing 330 000 oz/y over the first ten years, while remaining firmly in the lowest-cost quartile.

He says the attractive returns profile ensures this project will remain a capital allocation priority for the company and it demonstrates Endeavour’s ability to generate highly value-accretive projects, organically, through its pipeline.

“Our exploration team discovered Assafou in late 2021, and in less than three years we have defined a high-quality project with close to five-million ounces of high-grade indicated resource endowment.

“We expect that we will continue to grow the Assafou deposit’s resource, and delineate several exciting near-mine targets across the wider Tanda-Iguela property,” he says.

Given the excellent project economics, Cockerill notes that the company will now launch the DFS and simultaneously advance the permitting process so that it is well-positioned to potentially launch construction, with the company’s “best-in-class projects team”, in the second half of 2026.

“With a robust pipeline of organic growth opportunities, we expect to continue to unlock value and deliver long-term production growth towards our 1.5-million-ounce target, from a diversified portfolio of assets, by the end of the decade, while maintaining best-in-class margins.

“This underpins our capital allocation framework, and we expect to continue to deliver supplemental shareholder returns in line with our existing policy, and maintain attractive shareholder returns through this next growth phase,” he expresses.

MINING OPERATIONS

The Assafou deposit mineralisation extends from surface to depths in excess of 300 m and is amenable to conventional openpit mining.

The mine planning, resource and cost estimation for the PFS is based on a contract mining operation with a maximum mining capacity of 62.5-million tonnes a year.

Endeavour says mining capacity is expected to exceed processing capacity in order to accumulate stockpiles to allow high-grade material to be preferentially processed early in the mine life.

During the pre-commercial production period, about 36.5-million tonnes of pre-stripping is expected to support an accelerated ramp-up of the production profile.

The DFS will review opportunities to reduce the impact of pre-stripping at the Assafou deposit through supplementing the ore feed with near-surface ore from the Pala Trend 3 deposit, located 1 km from Assafou.

Diesel excavators and trucks will be used for loading and haulage, with a contractor fleet expected to comprise 300 t and 200 t class face excavators to load 140 t capacity dump trucks for waste mining, and 200 t class excavators to load 140 t capacity dump trucks for ore mining.

PROCESSING OPERATIONS

Ore will be processed at a five-million-tonne-a-year processing plant. Over the life-of-mine (LoM), the plant will be fed with about 89% fresh ore and 11% oxide and transitional ore.

The company says two-stage crushing, followed by a high-pressure grinding roll and a ball milling circuit, is planned.

A primary gyratory crusher will crush ore to a coarse crush size, followed by dual secondary cone crushers. This will feed a crushed ore stockpile that feeds into a high-pressure grinding roll circuit.

Ore will then be passed through a conventional ball mill and milled to 80% passing 106 microns.

The milled ore will pass through a gravity circuit comprising two Knelson concentrators for separation and recovery of coarse free gold, to produce a gravity concentrate for cyanidation and electrowinning that can be smelted to produce gold doré.

High gravity recovery of about 60% is estimated for fresh and oxide/transitional ores at Assafou.

The remaining milled gravity tail will be screened and passed to a carbon-in-leach (CIL) circuit containing one pre-leach tank and six CIL tanks in series for leaching and absorption. Leach residence time will be about 36 hours.

Following leaching and absorption, gold will be recovered from activated carbon by elution, electrowinning and gold smelting to produce gold doré.

Extensive and representative metallurgical testwork has indicated that gold is free milling with very high gravity and leach extraction potential, with a projected gold recovery rate of 94% over the LoM.

The DFS is expected to begin immediately and is due to be completed between late 2025 and early 2026.

Endeavour says updated mineral reserves and resources will be defined during 2025, which will include additional drilling at the Assafou deposits and the Pala Trend 3 satellite target, and will be incorporated into the DFS.

The exploitation permit application process and the environmental- and social-impact assessment submission are expected to begin in early 2025.