Sumitomo Metal Mining (SMM) has entered into agreements with Rio Tinto to acquire a 30% stake in the Winu copper-gold project, located in Western Australia’s Great Sandy Desert. The deal involves an investment of up to $430.4 million, with $195 million paid initially and up to $235.4 million in future payments tied to project milestones. Rio Tinto will maintain a 70% share and manage the project’s operations.

SMM director, managing executive officer and general manager of the Mineral Resources Division Hideyuki Okamoto and Rio Tinto Copper chief executive Katie Jackson signed the Winu joint venture agreements in Perth, Australia.

The partnership builds on a prior collaboration between the two companies at the Northparkes mine in New South Wales, which began in 2000. Following a term sheet signed in December 2024, the agreement also sets the stage for broader cooperation in copper, other base metals, and lithium, focusing on commercial, technical, and strategic opportunities. The transaction is expected to finalize in 2025, subject to regulatory approvals and standard conditions.

Katie Jackson, Rio Tinto Copper chief executive, stated: “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.”

Discovered in 2017, the Winu project holds estimated resources of 741 million tonnes, with a copper grade of 0.40% and gold at 0.33 grams per tonne, equating to about 3 million tonnes of copper and 250 tonnes of gold. The project is considered a low-risk, long-term asset with potential for expansion. SMM, which targets an annual copper production of 300,000 tonnes, sees Winu as a valuable addition to its global copper assets.

Rio Tinto is advancing a prefeasibility study for a mill with a 10-million-tonne annual capacity, set to conclude in 2025. Environmental permitting is underway, with an environmental review document submission planned for this year. The company is also working closely with the Nyangumarta and Martu Traditional Owners to negotiate project agreements.

SMM is supported by RBC Capital Markets for financial advice and Herbert Smith Freehills for legal counsel. The partnership aims to leverage the expertise of both companies to ensure the successful development of the Winu project while fostering sustainable collaboration with local communities.