Rio Tinto to offload minority stake in Winu copper project to Sumitomo Metal Mining

Rio Tinto has agreed to sell a 30% stake in the Winu copper project to Sumitomo Metal Mining for $399 million. The deal, comprising a $195 million upfront payment and $204 million in deferred considerations, reflects both companies’ intent to collaborate on one of Australia’s most promising copper-gold developments. Despite the sale, Rio Tinto will retain a 70% majority share and continue as the project operator.

This agreement highlights a pivotal moment for the Winu copper project, discovered by Rio Tinto in 2017. Situated in the Great Sandy Desert of Western Australia, the project represents a low-risk, long-life resource with significant potential for expansion.

Strategic partnership boosts copper ambitions

The stake sale cements a strategic partnership between Rio Tinto and Sumitomo Metal Mining, enabling them to pool expertise and mitigate investment risks. Beyond the equity transfer, the companies have signed a letter of intent to explore further collaborations in copper, lithium, and other critical metals vital for renewable energy technologies.

Sumitomo Metal Mining emphasized that the Winu copper project aligns with its goal of producing 300,000 tonnes of copper annually. The company views this acquisition as a strategic addition to its portfolio, which already includes stakes in key copper operations across Chile, Peru, and the United States. A senior representative from Sumitomo Metal Mining highlighted the company’s longstanding relationship with Rio Tinto, describing the partnership as a critical step toward mutual growth in the copper sector.

For Rio Tinto, the sale provides an opportunity to derisk the Winu copper project while retaining operational control. The company remains committed to advancing the project’s development, with a pre-feasibility study and environmental submissions slated for completion in 2025.

Focus on sustainability and collaboration

The Winu copper project is located on the traditional lands of the Nyangumarta and Martu peoples. Both Rio Tinto and Sumitomo Metal Mining are committed to ensuring the project respects and benefits these Indigenous communities. Negotiations with the Nyangumarta Traditional Owners are ongoing to formalize agreements that reflect shared interests.

In addition to its cultural considerations, the project is being designed with a focus on sustainability. Rio Tinto plans to submit an Environmental Review Document to Western Australia’s Environmental Protection Authority, demonstrating its commitment to meeting high environmental standards.

Industry implications and future growth

This stake sale comes at a time when global copper demand is surging, driven by renewable energy infrastructure and electric vehicle manufacturing. Analysts note that the Winu copper project has the potential to become a cornerstone in addressing this demand, especially with the combined expertise of Rio Tinto and Sumitomo Metal Mining.

The transaction also highlights the growing importance of strategic collaborations in the mining sector. By partnering with Sumitomo Metal Mining, Rio Tinto strengthens its position as a key player in delivering renewable energy metals while addressing sustainability challenges.

This milestone underscores the transformative potential of the Winu copper project and the broader collaboration between two mining giants.