Codelco has signed a Partnership Agreement with Rio Tinto that, it says, establishes the terms and conditions for the creation of a joint venture to develop a lithium project in the Maricunga Salt Flats of Chile.
The pact follows a process initiated in 2024 along with unanimous approval by Codelco’s board of directors.
The partnership with Rio Tinto will become effective once all necessary legal requirements are met, including consultations with regulatory bodies in Chile and abroad, yet to be defined, and the shareholders’ agreement and the formation of the joint venture are completed. The closing of the transaction is expected in the March quarter of 2026.
Rio Tinto and Codelco have expanded their ties in recent years. In 2022, they signed a collaboration agreement focusing on the accumulated experience of both companies in the design, construction and operation of underground mines.
In 2023, they agreed to collaborate with the objective of exchanging information in areas of mutual interest, such as the electrification of mining activities, the supply of desalinated water, stability and monitoring of tailings deposits, and the development of technologies for the decarbonisation of processes, among others. In that same year, they formalised the Nuevo Cobre joint venture.
The latest deal will see Rio Tinto acquire a 49.99% stake in Salar de Maricunga SpA, giving Codelco a 50.01% stake, in compliance with the National Lithium Strategy and the conditions established in the CEOL (Lithium Liability Company) submitted by the Ministry of Mining. Together, Codelco and Rio Tinto will define the roadmap for development at Maricunga, which will utilise new, competitive and sustainable technologies.
In financial terms, the agreement stipulates that Rio Tinto will contribute up to $900 million to the project, consisting of $350 million upon closing; $500 million upon final investment decision; and $50 million if the project generates first marketable lithium carbonate equivalent production by December 31, 2030.
The Maricunga Salt Flat has the second-highest lithium concentration among salt flats in the world after the Atacama Salt Flat, according to Codelco, and the joint venture will capitalise on the progress made in previous explorations, along with the engineering and environmental permitting already in place for the salt flat.
Codelco carried out its first exploration campaign in the area between 2022 and 2023, with the aim of constructing hydrogeological models and estimating mineral resources. In parallel, and with the aim of consolidating its position in the salar, in 2024 it acquired Lithium Power International (LPI), owner of Minera Salar Blanco SA.
Máximo Pacheco, Chairman of the Board of Codelco, said: “This process, which has been extraordinarily competitive, demonstrates the strategic value of lithium as a critical mineral, Codelco’s prestige as a partner and the attractiveness of our country as an investment location. The Codelco team has done a tremendous amount of work, involving various activities, such as visits to the Maricunga Salt Flats, presentations to interested parties, and ongoing responses to requests for information and questions.”
Jakob Stausholm, Chief Executive Officer of Rio Tinto, said: “We are honoured to be chosen as a partner with Codelco to develop a world-class project using Direct Lithium Extraction technology at the Salar de Maricunga, leveraging our expertise as a leading lithium producer for the global market. The development of this significant lithium resource will generate further growth and added value for our portfolio of critical minerals, essential for the energy transition.”