Rio Tinto is in active discussions to increase its stake in the Los Azules copper project in Argentina, as the mining major pushes to expand a copper production pipeline it has identified as central to its growth strategy. The conversations are described by McEwen Mining as progressing well, with Rio Tinto’s exposure currently held through its heap-leach technology subsidiary Nuton LLC.
Rio Tinto Los Azules: Strategic Context
Nuton invested approximately $100 million for its stake in McEwen Copper, a subsidiary of McEwen Mining (NYSE: MUX), according to McEwen’s February 2025 investor presentation. A larger position in Los Azules would give Rio Tinto (ASX/LSE: RIO) direct exposure to one of the few large, undeveloped copper porphyry deposits remaining in the Americas at a time when new discoveries are scarce and competition for quality assets is intensifying.
The project sits in San Juan Province, Argentina, at altitude in the Andes. A feasibility study published in October 2025 estimated an after-tax net present value of $2.9 billion, with first production targeted for 2030. Average output over the initial five years is projected at approximately 204,800 metric tonnes per year of copper cathode — a scale that would place Los Azules among the larger new copper developments globally.
Rio Tinto has publicly committed to building out its copper production base, framing the metal as a structural growth pillar alongside lithium and iron ore. The Los Azules talks reflect that mandate directly: the company has limited near-term organic copper growth and needs quality assets to fill the gap before the energy transition demand curve steepens further into the 2030s.
McEwen Copper Capital Raise and IPO Timeline
McEwen Copper is seeking approximately $4 billion in initial capital to develop Los Azules. The company has indicated it plans an initial public offering of around $300 million, targeting launch toward the end of 2026, though no formal timeline has been confirmed.
The existing shareholder register includes two strategically significant investors beyond Nuton. Automaker Stellantis holds an 18.3% stake in McEwen Copper, having invested approximately $275 million as part of the carmaker’s broader drive to secure raw materials for electric vehicle batteries. The Stellantis position reflects a wider trend of downstream manufacturers taking equity stakes in upstream copper and lithium projects to reduce supply chain exposure as EV production volumes scale.
Rio Tinto ranks among the world’s top copper producers, with its Oyu Tolgoi underground mine in Mongolia ramping toward full production and the Kennecott smelter in Utah undergoing a major modernisation programme. Los Azules would add a South American dimension to a portfolio currently weighted toward Mongolia, the US, and its legacy Escondida stake in Chile.
Los Azules and the Copper Supply Gap
The copper market faces a well-documented supply deficit in the second half of this decade. Existing mines are ageing, grades are declining, and the permitting and development timelines for new projects mean that assets like Los Azules — with a completed feasibility study and a 2030 production target — carry meaningful scarcity value.
A Rio Tinto stake increase would likely be structured to preserve McEwen Copper’s independence ahead of the planned IPO while giving Rio optionality on a larger position post-listing. Whether Nuton’s involvement deepens into a controlling or significant minority stake remains unconfirmed. McEwen Mining has not disclosed terms or a timetable for any transaction.
For the South American critical minerals sector, Los Azules represents one of the region’s most advanced large-scale copper development projects outside established Chilean and Peruvian operations. Argentina’s mining investment environment has improved under the Milei administration’s pro-investment policy stance, which has reduced some of the sovereign risk concerns that previously weighed on project timelines in San Juan Province.
Further details on Rio Tinto’s broader critical minerals strategy — including its Arcadium lithium acquisition and copper growth targets — are covered in CMN’s company profile.
What is Rio Tinto’s current stake in Los Azules?
Rio Tinto holds its interest through Nuton LLC, its heap-leach copper technology subsidiary, which invested approximately $100 million for a stake in McEwen Copper. The size of that stake has not been publicly disclosed by McEwen Mining.
What does the Los Azules feasibility study say about production?
The October 2025 feasibility study estimates an after-tax net present value of $2.9 billion. Average copper cathode production over the first five years is projected at approximately 204,800 metric tonnes per year, with first production targeted for 2030.
Who else owns a stake in McEwen Copper?
Stellantis holds an 18.3% stake in McEwen Copper, having invested around $275 million to secure raw materials for its electric vehicle battery supply chain. Nuton LLC (Rio Tinto) is also a shareholder alongside McEwen Mining itself.
How much capital does Los Azules need to reach production?
McEwen Copper is seeking approximately $4 billion in initial capital. The company has indicated plans for an IPO of around $300 million toward the end of 2026 to contribute toward that total.
Why is copper consolidation accelerating among major miners?
New copper discoveries are scarce and existing mines face declining grades. Demand from EV manufacturing, power grids, and data centre infrastructure is projected to create a supply deficit later this decade, making large undeveloped assets like Los Azules highly competitive acquisition targets.
