Rio Tinto Group has held talks with the Democratic Republic of Congo about developing one of the world’s biggest hard rock lithium deposits, in the latest sign of the miner’s enthusiasm for the battery metal.

The conversations in recent weeks with Congolese authorities focused on Rio getting involved in transforming the Roche Dure resource into a lithium mine, according to people familiar with the matter. The discussions are at a preliminary stage and might not result in any agreement, the people said.

Securing investment from a western firm of Rio’s size would be a significant boost for the central African nation’s leaders as they try to curb the dominance of Chinese companies in the country’s key mining sector. Congo is in early-stage discussions with President Donald Trump’s administration about a possible minerals-for-security deal with the US to aid the fight against a Rwanda-backed rebellion in its eastern provinces.

Should Rio secure a deal, it would signal an escalation in the miner’s appetite to operate in some of the world’s most challenging jurisdictions. While the company has already shown it’s more willing to operate in difficult places — it has major projects in Guinea and Mongolia — a Congo operation would further differentiate it from its main rival BHP Group, which has long preferred more stable regions.

Rio is not the only miner eyeing the Roche Dure lithium deposit, which was first defined by Australia’s AVZ Minerals. Bloomberg News reported last week that KoBold Metals – a California-based exploration firm backed by billionaires including Bill Gates and Jeff Bezos – told Congo’s government in January that it’s keen to develop the project once disputes over the mining rights are settled.

One option under consideration is KoBold and Rio teaming up to build and run the mine together, some of the people said, asking not to be identified discussing private information. However, both companies are interested in the project separately and there’s no guarantee they would choose to forge a partnership, according to the people.

The sought-after license near Manono in southeastern Congo is claimed by AVZ, which has initiated arbitration proceedings to recover the asset. AVZ said in 2020 it was planning to build a facility capable of producing 700,000 of lithium concentrate a year for two decades. That would be the biggest mine of its kind outside Australia.

Perth-based AVZ carried out exploration works and was close to breaking ground on construction when the government canceled its rights in 2023. Congo split the permit and handed the northern part to China’s Zijin Mining Group. Roche Dure is located in the southern section.

Unlike BHP and Glencore, which have mostly shunned lithium, Rio is pushing to become a major player in the supply chain of the metal used in electric-vehicle batteries. Taking advantage of a crash in prices driven by oversupply, the company is aggressively expanding its business, targeting large projects it believes will be among the lowest cost in the industry.

Rio – one of the world’s biggest exporters of iron ore and suppliers of aluminium, as well as a growing copper producer – agreed last year to buy Arcadium Lithium for $6.7-billion.

That adds to assets it’s developing in Serbia and Argentina, where the Rincon project is already producing. Rio plans to ramp up lithium output as the market tightens toward the end of the decade.

Spokespeople for Rio, KoBold and AVZ declined to comment. Spokespeople for Congo’s presidency and mines ministry didn’t respond to requests for comment.