Rio Tinto and Sumitomo Metal Mining (SMM) have entered into joint venture (JV) agreements to develop the Winu copper-gold project in Western Australia’s Great Sandy Desert.
As part of this, Sumitomo will be investing up to $430.4m for a 30% equity stake in the JV.
The JV deal follows a preliminary term sheet set in December 2024.
Under the terms, Rio Tinto will retain operational control of the Winu project. Sumitomo’s investment includes an upfront payment of $195m and deferred considerations potentially reaching $235.4m, contingent on future project milestones.
SMM director, managing executive officer, and mineral resources division general manager Hideyuki Okamoto said: “We are very excited to renew our long-standing partnership with Rio Tinto, and to leverage our extensive collective experience to realise the exceptional potential of the Winu project.”
Both companies are exploring broader collaboration opportunities beyond Winu, focusing on commercial and technical ventures in the copper, base metals, and lithium sectors. The deal’s closing is anticipated to occur this year, pending regulatory approvals and standard conditions.
Rio Tinto is working with Nyangumarta and Martu Traditional Owners on ongoing project agreements. A pre-feasibility study for Winu is scheduled for completion in 2025, alongside an environmental review document as part of the Western Australian Environmental Protection Agency (EPA)’s assessment process.
The initial phase plans for a processing capacity of up to 10 million tonnes per annum.
The Winu site is located approximately 320km east of Port Hedland in the Pilbara region, situated on Nyangumarta traditional lands, with its servicing airstrip on Martu lands.
Discovered by Rio Tinto in 2017, the company has collaborated closely with local stakeholders to establish a sustainable mining operation.
Plans include powering the site mainly with renewable energy sources such as solar and wind. Considerations for mine closure are underway, focusing on waste management, community impact minimisation, and site remediation post-closure.
Rio Tinto copper chief executive Katie Jackson said: “Our relationship with SMM began in 2000 with our partnership at the Northparkes mine in New South Wales and we look forward to bringing our combined experience and expertise to deliver the Winu project.
“This partnership is an excellent fit for Rio Tinto and will strengthen the project, as we continue to prioritise the strong and enduring partnerships built to date with the land’s Traditional Owners, the Nyangumarta and the Martu.”
