Glencore and Rio Tinto have abandoned discussions over a potential merger that would have created one of the world’s largest copper producers, after failing to agree on valuation and governance terms, according to statements issued by the companies on Monday.
Glencore said it had taken note of an announcement by Rio Tinto confirming that it does not intend to make an offer for the Swiss-based miner. As a result, Rio Tinto is now subject to the restrictions under Rule 2.8 of the UK Takeover Code, which prevents it from launching a bid for a defined period.
According to Glencore, the parties were unable to reach agreement on the terms of a possible combination. The miner indicated that the proposal under discussion would have seen Rio Tinto retain both the chairman and chief executive officer roles in the combined group, while offering Glencore shareholders an ownership structure that, in its view, materially undervalued Glencore’s contribution.
Glencore said the proposal did not adequately reflect its long-term, through-the-cycle value, particularly in relation to its copper business, its pipeline of growth projects and the potential allocation of synergies. On that basis, the board concluded that the transaction was not in the best interests of its shareholders.
The company reiterated its confidence in its standalone strategy, pointing to its diversified portfolio across multiple commodities, its global marketing business and its exposure to both current energy supply and energy-transition metals. Glencore also highlighted recent operational simplification and its delivery of production within guidance ranges for key commodities for a second consecutive year.
Copper remains central to Glencore’s growth ambitions. The company said it has built a portfolio of copper projects that could see it become one of the world’s largest producers over the next decade.
Argentina features prominently in those plans. Glencore is targeting investments of around US$14 billion in the El Pachón and Mara copper projects, located in the provinces of San Juan and Catamarca, respectively. The investments are expected to be channelled through Argentina’s Large Investment Incentive Regime (RIGI), which offers tax and fiscal stability for up to 30 years.
El Pachón is regarded as the more complex of the two developments, as it requires new infrastructure, logistics capacity and the construction of a concentrator plant. Once operational, it is expected to produce an average of approximately 359,000 tonnes of copper per year over a mine life of around 40 years. Glencore expects to receive approval under the RIGI framework in the coming months and is targeting first production in 2034.
At the Mara project, Glencore plans to restart operations at the Alumbrera copper and gold mine by the end of 2026, with first production expected in the first half of 2028. Alumbrera is projected to produce about 75,000 tonnes of copper, 317,000 ounces of gold and 1,000 tonnes of molybdenum annually for four years. The restart is intended to reduce commissioning risk for the broader Mara development and preserve critical infrastructure to generate operational synergies.
Rio Tinto, meanwhile, said it will continue to pursue its standalone expansion strategy, as outlined to investors in December 2025. While lithium remains a major focus in Argentina — where the group already has installed capacity of around 85,000 tonnes per year and is advancing the Rincón project — copper also remains a strategic priority.
Although Rio Tinto does not currently own copper assets in Argentina, it has established a local presence through Nuton, a subsidiary developing bioleaching technology aimed at improving copper recovery rates and unlocking value from ores that are difficult to process using conventional methods. The technology has already produced copper cathodes and is being tested at McEwen Mining’s Los Azules project, where Nuton holds a 17.2% stake.
Both Glencore and Rio Tinto currently produce more than 800,000 tonnes of copper per year across their global portfolios and are targeting output of around one million tonnes annually by the end of the decade — a scale that helps explain why the prospect of a combination attracted significant market attention, even if strategic differences ultimately prevented a deal.