Aterian plc $ATN (+0%) has regained full control of its HCK project in the Southern Province of Rwanda following Rio Tinto Mining and Exploration Limited's decision to terminate the joint venture.

Rio Tinto $RIO (+0.17%)
$RIO (-0.69%) concluded that the area did not have the required scaling potential for a lithium mine to meet the Group's Tier 1 specifications.

The company had previously invested US$4.73 million in exploration activities including surface geological mapping, geochemical sampling, ground-based geophysical surveys and four diamond core holes.

The termination of the joint venture comes despite Rio Tinto's announcement in July that it intended to exercise its Stage 1 earn-in rights under the joint venture agreement.

On-site exploration had returned a high-grade lithium drill intercept of 6.90m at 2.11% Li₂O, including an intercept of 3.45m at 3.20% Li₂O. Aterian will now focus on developing the tantalum, niobium and lithium potential of the project.

"The return of ownership of the HCK project is an opportunity for Aterian to unlock value on our own terms, particularly through the targeted mining of tantalum and niobium," said Charles Bray, Chairman of Aterian, in the press release.

Aterian plans to integrate the technical data collected by Rio Tinto into its own regional datasets to accelerate the identification and prioritization of mineral targets. The company also intends to attract new strategic partners to monetize the broader business opportunities in Rwanda.

According to the company, the termination of the joint venture is not expected to have a material adverse effect on its short-term operations. Regaining control of the project is seen as a strategic opportunity.