Rio Tinto and Sumitomo Metal Mining Co. have signed definitive agreements to establish a joint venture for the Winu copper-gold project in Western Australia's Great Sandy Desert.

The agreement was finalized in Perth by Katie Jackson, chief executive of Rio Tinto Copper, and Hideyuki Okamoto, director, managing executive officer, and general manager of the Mineral Resources Division at Sumitomo Metal Mining (SMM). The signing follows a term sheet agreed upon in December 2024.

Discovered by Rio Tinto in 2017, the Winu project is a low-risk, long-life copper-gold deposit with significant potential for future expansion. Under the terms of the agreement, Rio Tinto will continue to lead development and operation of the project, while SMM will acquire a 30% equity stake.

SMM will pay up to $430.4 million for its share, including $195 million upfront and up to $235.4 million in deferred payments contingent upon key project milestones. The transaction is expected to close in 2025, pending regulatory approval and other customary conditions.

“This partnership is a natural evolution of our long-standing relationship with SMM, which began in 2000 at the Northparkes mine in New South Wales,” Jackson said. “Their investment and expertise will strengthen the Winu project as we continue building enduring relationships with the Traditional Owners of the land — the Nyangumarta and Martu peoples.”

Okamoto echoed the sentiment, saying: “We are pleased to renew our collaboration with Rio Tinto and apply our shared experience to unlock Winu’s potential. This project aligns with our long-term commitment to sustainable resource development.”

In addition to advancing Winu, the companies intend to explore further commercial, technical and strategic partnerships focused on copper, other base metals, and lithium.

Rio Tinto remains committed to working closely with the Nyangumarta and Martu Traditional Owners. The company is progressing Project Agreement negotiations and prioritizing responsible development practices.

A pre-feasibility study for Winu is currently underway and is expected to be completed in 2025. The study will assess an initial processing capacity of up to 10 million tonnes per annum. Rio Tinto also plans to submit an Environmental Review Document as part of the Western Australian Environmental Protection Authority’s assessment process.

The Winu project represents a key opportunity in Rio Tinto’s copper portfolio as global demand for energy transition minerals continues to grow.

Rio Tinto is a global mining and metals corporation and one of the largest in the world, operating across 35 countries. The company is dedicated to supplying materials vital to human advancement, with a strong emphasis on supporting the energy transition. Its primary products include iron ore, copper, aluminium, and other essential minerals.