McEwen’s $4 billion copper plan puts Rio Tinto in focus
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McEwen Copper is in talks with Rio Tinto and other investors as it seeks about $4 billion to develop the Los Azules copper project in Argentina.
The talks come as McEwen works to move one of Argentina’s largest undeveloped copper deposits toward production by around 2030. Its financing plan could include about $600 million in equity from existing shareholders, including Rio Tinto, and another $600 million from a new investor. Debt would provide much of the remaining capital.
McEwen is also preparing for a possible initial public offering as soon as the fourth quarter of 2026. Chairman Rob McEwen said the IPO could raise about $300 million, although the timing will depend on market conditions.
The size of the funding package shows one of the main problems facing large copper projects. Strong demand and attractive project economics may support the investment case, but developers still need to secure billions of dollars before construction can begin.
Rio Tinto could bring more than capital to Los Azules
Rio Tinto already has a direct interest in McEwen Copper through its Nuton business, which owns about 17% of the company. McEwen Inc. remains the largest shareholder with about 46%, while automaker Stellantis owns roughly 18%.
That existing relationship gives Rio Tinto more knowledge of the project than a new financial investor would have.
Nuton has been working with Los Azules as McEwen studies the use of leaching technology at the project. Rio Tinto says the process can extract copper from primary sulphide ore using microorganisms. It could allow copper cathode to be produced at the mine without a conventional concentrator, smelter or tailings facility.
Rio Tinto says Nuton has achieved recovery rates of up to 85% from primary sulphide ore and could reduce processing costs by up to 40% compared with traditional methods. Those figures describe the technology more broadly and should not be treated as guaranteed results at Los Azules.
Rio Tinto’s familiarity with the deposit may also have value as McEwen works through financing and development decisions. McEwen Copper Managing Director Michael Meding has said the miner has an advantage because of its years of involvement with the project.
However, talks are still underway. McEwen is also speaking with other possible investors, so a larger Rio Tinto commitment is not certain.
Financing will decide whether Los Azules becomes a mine
Los Azules has passed several major technical and regulatory milestones, but financing remains one of the biggest barriers between the project and construction.
A feasibility study released in October 2025 estimated initial capital spending of about $3.17 billion. It projected average copper cathode production of about 204,800 metric tons a year during the first five years and roughly 148,200 metric tons a year over a 21-year mine life.
The study estimated an after-tax net present value of $2.9 billion and an internal rate of return of 19.8%. It also proposed producing 99.99% copper cathode at the site through a leach and solvent extraction-electrowinning process, avoiding the need for a smelter.
Those figures give potential investors a clearer view of the project’s economics. They do not remove the challenge of assembling a multibillion-dollar funding package.
In May, McEwen Copper appointed Societe Generale to advise on project debt. The financing could involve export credit agencies, commercial banks, multilateral lenders, development finance institutions and capital markets.
McEwen also has a collaboration agreement with the International Finance Corp. linked to environmental, social and governance standards for international project financing.
This mix of potential funding sources shows how large mining projects are financed. Strategic equity alone is rarely enough. Developers often need bank debt, government-backed credit, institutional capital and public market funding before they can commit to full construction.
For Los Azules, the terms of that funding will matter almost as much as the amount. McEwen needs to raise enough capital to maintain its development schedule without placing too much pressure on existing shareholders or weakening the project’s economics.
Los Azules will test Argentina’s ability to attract mining capital
The financing effort also matters beyond McEwen.
Los Azules received approval under Argentina’s Large Investment Incentive Regime in September 2025. McEwen says the framework provides tax, foreign exchange and customs stability for 30 years, as well as access to international arbitration.
The policy is intended to give investors more certainty when they back projects expected to operate for decades.
Los Azules now offers an early test of whether those measures can attract the scale of international capital required for a major copper development.
The wider copper market supports the case for new production. Copper is widely used in power grids, electrical equipment, renewable energy systems and electric vehicles. New mines are expected to play an important role in meeting future demand.
But market demand alone will not put Los Azules into production.
McEwen still needs to complete detailed engineering, secure outstanding permits and agree on financing terms that can support a final investment decision.
The talks with Rio Tinto therefore mark an important point in the project’s development. Los Azules has moved beyond proving that it contains a large copper resource. McEwen must now show that the project can attract enough committed capital to become a producing mine.
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