First Quantum Minerals is in talks to sell a stake in one of the world’s biggest undeveloped copper projects as rival miners and strategic investors rush to boost exposure to the metal.

First Quantum, which has copper mines in Zambia and Panama, is running a process to sell a minority stake in its Taca Taca project in Argentina, according to people familiar with the situation, who asked not to be identified because the talks are private.

Potential buyers include Rio Tinto Group, the world’s second biggest miner, and Japanese trading houses Mitsubishi Corp. and Mitsui & Co, the people said.

Representatives for First Quantum, Rio Tinto, Mitsubishi and Mitsui declined to comment.

The world’s biggest miners are looking to bulk up in copper, a crucial metal for the energy transition that is trading near record highs. Forecasts of future deficits have fuelled a wave of attempted deals in the sector.

The Taca Taca deposit is situated close to the Chile border and could produce more than 320,000 tons of copper a year at its peak, or about 1.5% of current global mine supply.

First Quantum is viewed as one of the best mine builders in the copper industry. However, it’s been beset by problems at its flagship mine in Panama, which was closed in late 2023 after mass protests against the operation.

It has already forged a relationship with Rio. In 2023, it bought a majority stake in the La Granja copper project in Peru from Rio, and they’re planning to develop the asset together. Former Rio CEO Jakob Stausholm also visited First Quantum’s copper mine in Panama.

The sale process is at an early stage and there are no guarantees an agreement will be made, some of the people said.

Building copper mines of the size of Taca Taca can cost billions of dollars and take years to complete. That’s made selling minority stakes a common approach in the industry as a means of sharing the cost and risk.

BHP Group and Glencore Plc already own massive copper projects in Argentina, which is rapidly becoming one of the hottest locations as miners seek out new deposits. President Javier Milei has moved to unlock investment by easing restrictions, including changes to glacier protections, and introducing incentives covering tax, customs and foreign-exchange rules.

The government is seeking to position Argentina as a major copper supplier, tapping rising demand driven by electrification and other industrial uses. But a lack of established infrastructure remains a hurdle for mining projects.