Aterian Plc, a UK-based critical minerals exploration company, announced that it has found high-grade lithium deposits in Rwanda, following a drilling exercise in collaboration with Rio Tinto Mining and Exploration Ltd, a British-Australian mineral exploration multinational company.

“The initial results confirm the presence of high-grade lithium mineralisation and demonstrate the prospectivity of the HCK Project,” the company said in a statement released on July 10.

HCK Project is a joint venture between Aterian and Rio Tinto. Under the project, the two firms kicked off drilling activities in September 2024 in the Southern Province.

Aterian, a London Stock Exchange (LSE) listed company, revealed that one drill hole in particular, known as MWOG0002, reached a depth of 174.6 meters and uncovered a 6.9-meter section of lithium-bearing rock grading 2.11 per cent lithium, containing a higher-grade interval of 3.45 metres at 3.20 per cent lithium.

Drilling was conducted on only two of the twelve defined prospect areas by Rio Tinto.

As a result, Rio Tinto announced that it will exercise its Stage 1 earn-in rights under the joint venture agreement, allowing it to own a 51 per cent interest in the HCK license.

This means that its interest in the license will increase to 75 per cent upon investing $7.5 million over a period of three years, as indicated in the agreement.

Simon Rollason, CEO of Aterian, said that they are encouraged that Rio Tinto has exercised its Stage 1 earn-in rights following the completion of the initial Stage 1 exploration programme.

He noted that during this phase, only two of the twelve prospects identified during Rio Tinto's fieldwork were tested, and the potential exists to identify less weathered areas where additional lithium-rich rocks may occur.

“While further work is required to fully assess the project's scale and continuity, these early indications provide a strong foundation to build upon as we advance our exploration activities in Rwanda,” he said.

Dubbed “white gold” for electric vehicles (EVs), lithium plays a critical role in the cathodes of all types of lithium-ion batteries that power EVs, although it is also used in the batteries of laptops and cell phones, as well as in the glass and ceramics industry.

Rollason noted that there will be additional work to further evaluate the scale, continuity, and development potential of the mineralisation given the weathering profile.

“A comprehensive technical review is currently underway to determine the optimal next phase of exploration. A JV decision regarding the forward work programme is anticipated by the end of 2025,”he noted.

The joint venture agreement signed in 2023 allowed for the exploration and development of lithium and by-products, through a project that boasts 19 identified pegmatite zones for lithium, cesium, and tantalum on 2,750 hectares of land in Southern Province.

As of July 2024, Rwanda’s mining sector contributed about 3 per cent to the country’s economic output and employs more than 72,000 people. The sector boosts $150 billion revenue potential.