Rio Tinto and Codelco, Chile’s state-owned copper mining company, have signed agreements to form a joint venture for the Salar de Maricunga lithium project in Chile’s Atacama region, with Rio Tinto investing up to $900 million. The project targets a lithium-rich brine deposit, noted for one of the highest average lithium grades globally.

Rio Tinto will hold a 49.99% stake in the JV under the deal.

Under the agreement, Rio Tinto will acquire a 49.99% stake in Salar de Maricunga SpA, the entity holding Codelco’s licenses and concessions for the project. Rio Tinto will provide $350 million initially to fund studies and development, with an additional $500 million for construction upon project approval. A further $50 million will be invested if the joint venture achieves its first lithium production by the end of 2030. The deal is expected to close by the end of March 2026, pending regulatory approvals and standard conditions.

Rio Tinto CEO Jakob Stausholm stated: “We are honoured to be chosen as Codelco’s partner to deliver a world-class project using Direct Lithium Extraction technology in the Salar de Maricunga, leveraging our expertise as a leading producer of lithium for the global market.” He added: “Codelco is a strategic partner for Rio Tinto in Chile, with this agreement building on our copper joint ventures.”

Codelco chairman Máximo Pacheco said: “This project continues our lithium diversification strategy, which is essential for the energy transition, with a world-class partner in Rio Tinto that represents the most attractive option for Codelco and the country. We are happy and proud to strengthen our partnership with a company of Rio Tinto’s prestige, and we warmly welcome it as a partner in this important project for Chile.”

The joint venture will focus on updating reserve and resource estimates, advancing technical studies, and engaging with local communities to support sustainable development. Both companies will contribute capital based on their ownership shares and prioritize advanced extraction technologies to maximize recovery while minimizing environmental impact, including shared infrastructure to reduce water usage.

This partnership builds on Rio Tinto’s January 2025 announcement to create a dedicated lithium division following its $6.7 billion acquisition of Arcadium Lithium, reinforcing its commitment to critical minerals for the energy transition.