Rio Tinto and Codelco join forces on major Chilean lithium project in US$900 million deal

Rio Tinto Ltd has struck a landmark deal with Chilean state miner Codelco to jointly develop a high-grade lithium project in the Salar de Maricunga, tapping further into the intensifying global race for critical minerals.

Under binding agreements announced today, Rio will acquire a 49.99% stake in Salar de Maricunga SpA – the Codelco-owned entity holding licences and concessions in the lithium-rich salt flat – by funding up to US$900 million across project studies and development stages.

The initial investment includes US$350 million for further technical studies and resource analysis, with an additional $500 earmarked to support construction once a final investment decision is made, anticipated by the decade’s end. A further US$50 million payment will be triggered if the joint venture achieves first production by 2030.

Rio Tinto chief executive Jakob Stausholm said the company was “honoured” to be Codelco’s partner in the world-class project using direct lithium extraction technology. Rio Tinto and Codelco are strategic partners in Chile, and the agreement builds on their copper joint ventures.

“Developing this significant lithium resource will deliver further value-adding growth in our portfolio of critical minerals essential for the energy transition,” Stausholm said.

“We aim to bring significant investment and long-term benefits to the Atacama region as we advance Maricunga and Nuevo Cobre together, with a focus on responsible sustainable development including shared infrastructure and solutions to minimise water usage,” he added.

Tapping into a national strategy

Located in Chile’s Atacama region, Salar de Maricunga is regarded as one of the world’s highest-grade undeveloped lithium brine resources, second only to the Salar de Atacama – home to operations by SQM and Albemarle. The region’s lithium-rich brines are in growing demand for electric vehicle (EV) batteries and other renewable technologies.

The joint venture builds on Rio’s existing partnerships with Codelco in copper and aligns with Chile’s national strategy to assert greater state control over lithium production. The Chilean government has tasked Codelco and ENAMI with leading public-private lithium ventures to ensure strategic oversight while attracting foreign investment.

Codelco chairman Máximo Pacheco said the Rio partnership was a critical step in the company’s lithium diversification.

“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 to this important project for Chile,” he said.

Direct lithium extraction

The partners plan to use direct lithium extraction – a newer, less water-intensive technology that extracts lithium from brine with higher efficiency and lower environmental impact than traditional evaporation ponds. The joint venture will also focus on shared infrastructure development, water stewardship and community engagement in the Altacama.

Rio’s lithium push has accelerated in recent years following its 2021 acquisition of the Rincon Lithium Project in Argentina and ongoing exploration in Serbia and the US. The Maricunga deal strengthens Rio’s foothold in South America’s lithium triangle, which spans Chile, Argentina and Bolivia – home to more than half of the world’s lithium resources.

The transaction is expected to close by the end of the first quarter of 2026, pending regulatory approvals and other customary conditions.