The pair has inked a memorandum of understanding to support the ongoing prefeasibility study into the development of the platinum group elements-nickel-copper-cobalt project, covering technical, financing, marketing and offtake aspects.
While the agreement is non-binding, Chalice and Mitsubishi hope to finalise terms within 90 days of the delivery of the PFS, targeted for mid-2025.
The agreement follows Mitsubishi and Sumitomo agreeing to back studies in Ardea Resources’ similarly large Goongarrie Hub nickel laterite development near Kalgoorlie.
“From the outset of the strategic process, Mitsubishi was always considered one of the most impressive and best suited strategic partners for the Gonneville project, based on its decades-long development, operational and trading track record,” Chalice managing director Alex Dorsch said.
He said the pair had been involved in talks for the past year, with the MoU structured to provide a framework for collaboration for both parties during the PFS, helping derisk the project ahead of any potential joint arrangement and investment.
“(It) highlights the longer-term strategic nature and value of the project as a potential large-scale, long-life and low-carbon source of critical minerals for Western markets,” Dorsch said.
Mitsubishi battery minerals general manager Kota Ikenishi said the conglomerate viewed Gonneville as having “the potential to become a large-scale, globally significant critical minerals asset, and its US IRA-qualifying suite of metals could have a strategic importance for Japan in the future”.
Mitsubishi’s decision to sign on comes despite recent metallurgical test work that flagged some challenges in refining the flowsheet.
Chalice has estimated the PFS will cost about A$15 million to complete, with the company having about $107 million cash at the end of March.
Chalice delivered its original scoping study last year, but the market baulked at the size and scale of the $2.3 billion, 30 million tonne per annum undertaking, so the company reframed a more manageable, higher-grade, and selective mining operation in April.
The higher-grade starter project would target recovering 59Mt grading two grams per tonne 3E PGE, 0.2% nickel, 0.21 copper and 0.019 cobalt, which should allow recovery of 3.8 million ounces palladium-platinum-gold, 120,000 tonnes nickel, 120,000t copper and 11,000t cobalt.
Half of the resource is within 200m of surface.
Total resources at Gonneville are 660Mt at 0.79gpt PGE, 0.15% nickel, 0.083% copper and 0.015% cobalt for 17Moz PGE, 960,000t nickel, 540,000t copper and 96,000t copper.
Chalice hopes to start construction in 2027, and be in production in 2029, just a decade after discovery.
