ASX-listed Chalice Mining has announced a metallurgical breakthrough at its Gonneville project, in Western Australia, successfully producing saleable copper and nickel concentrates from low-grade material. 

This development, the company says, eliminates the need for a complex and costly hydrometallurgical process, reducing both technical risk and capital expenditure.

Recent testwork has confirmed that two smelter-grade flotation concentrates can be produced across the entire Gonneville sulphide resource. The copper concentrate grades between 22% and 26% copper, with 45 g/t to 60 g/t of palladium, platinum, and gold. The nickel concentrate contains between 7.5% and 8.7% nickel, along with 0.8% cobalt and 18 g/t to 20 g/t of palladium, platinum, and gold. 

In addition, conventional carbon-in-leach (CIL) has been optimised to recover extra palladium and gold from flotation tails, with significantly reduced reagent consumption and operating costs compared with the 2023 scoping study. The CIL process is expected to qualify for Australia’s recently legislated Critical Minerals Production Tax Incentive, providing a 10% tax offset on operating costs.

Testwork and process refinements will continue through the first quarter of 2025, with completion of the prefeasibility study targeted for mid-year. Chalice remains in a strong financial position, holding A$90-million in cash and listed investments as of December 31, 2024.

Chalice MD and CEO Alex Dorsch described the breakthrough as a step change that fundamentally simplifies the Gonneville project. “The ability to produce a saleable nickel concentrate across the grade spectrum of the entire Gonneville resource is a major breakthrough and fundamentally simplifies the world-class Gonneville project. This is the step change we have been hoping for over the last two years."

"Removing the need for a hydrometallurgical process materially reduces both the capital and operating costs," Dorsch said. "Together with the optimisations being introduced to the flowsheet, this is expected to deliver a significant improvement in project margins across all high-grade and low-grade phases of a bulk openpit mine plan. The simplified flowsheet also has much lower risk profile and gives the project a smoother and more rapid pathway to development."

He added that ongoing testwork continues to enhance the project’s economics. “Gonneville is a unique deposit, and it has taken time to ‘crack the code’ on the metallurgy. The project continues to improve as we refine our approach.”