• Aterian ends joint venture with Rio Tinto on Rwanda lithium project
• Rio Tinto exits after $4.7M investment, citing inconclusive results
• Aterian to refocus on tantalum, niobium potential at HCK site

London-listed Aterian Plc said on Oct. 31 that it has ended its joint venture with mining giant Rio Tinto on the HCK lithium and tantalum exploration project in Rwanda.

The decision follows what the companies described as inconclusive exploration results. Aterian said it will continue to advance work on the exploration license, in which it holds a 70% stake alongside Rwanda’s HCK Mining, which owns 30%.

The partnership, signed in 2023, had allowed Rio Tinto to earn an interest in the project by funding exploration activities. The company invested about $4.7 million and completed four diamond drill holes before deciding to withdraw. Rio Tinto concluded that the HCK project “does not have the potential to support a mine meeting the lithium resource specifications required by a major mining company.”

Aterian said it would build on the work already completed to further assess the site’s potential. “Aterian will now regain control of the Project, and the Company believes this provides an exceptional opportunity to unlock the broader value of the licence area, where significant tantalum, niobium and lithium mineralisation potential remains untested,” the company said in a statement. “The Company may now directly capitalise on the extensive exploration investment already completed and maximise the full critical mineral potential of HCK-including high-grade tantalum and niobium systems that have historically supported local artisanal mining.”

The company has not yet released an updated exploration plan or schedule for the HCK project. Aterian said it will analyze existing data from previous work to identify new targets, with a renewed focus on tantalum and niobium. These two minerals are already central to the trading platform the company is developing in Rwanda, where it currently sources material from artisanal and small-scale miners.

Aurel Sèdjro Houenou