Rio Tinto is conducting an internal evaluation of the economic potential of the Los Azules copper project in Argentina and is contemplating increasing its existing 17.2% stake, according to industry sources. The interest in Los Azules - ranked among the world’s 10 largest undeveloped copper deposits - comes as major miners prioritize large-scale copper assets to meet rising demand from data centres and the global clean energy transition.
The miner holds its position in Los Azules through Nuton LLC, its copper technology venture. Sources familiar with the matter said Rio Tinto’s technical team is assessing the project's economics while trials of Nuton’s proprietary leaching technology are under way at the site.
Rio Tinto declined to comment on the review.
"We are obviously discussing with our existing partner Nuton because their technology makes so much sense," Michael Meding, managing director at Canadian miner McEwen Copper, said. "Now that Rio Tinto is building their copper pipeline, they basically have a mandate to add copper for their production profile. So we are having fruitful conversations."
Securing a larger interest in Los Azules would strengthen Rio Tinto’s pipeline of copper projects at a time when new discoveries are limited and competition for high-quality deposits is intense, the sources said. The push toward organic growth through stakes in undeveloped deposits has become a focus for Rio following the collapse of merger talks with Glencore.
Nuton initially invested about $100 million to acquire its stake in McEwen Copper, which is a subsidiary of McEwen Mining, according to McEwen’s investor presentation. Alongside Nuton, automaker Stellantis holds an 18.3% stake in McEwen Copper, having put in roughly $275 million as part of its efforts to secure raw materials for electric vehicle batteries.
McEwen Copper is seeking approximately $4 billion in initial capital to move Los Azules into development. A feasibility study released in October 2025 estimated an after-tax net present value of $2.9 billion for the project, which targets first production by 2030. The study projects average production over the first five years at about 204,800 metric tons per year of copper cathode.
The company has also indicated plans for an initial public offering of about $300 million toward the end of this year as part of its funding strategy.
As Rio Tinto evaluates the site and Nuton’s technology is trialled on location, the economic and technical assessments will be central to any decision to increase its stake. The combination of sizeable capital requirements, ongoing technical validation and broader competition for copper assets frames the immediate outlook for Los Azules and its current investors.