Aterian and Rio Tinto Hit High-Grade Lithium at Rwanda’s HCK Project in Early Drilling Results
Critical minerals developer Aterian has announced encouraging results from the initial diamond drilling campaign at the HCK lithium project in Rwanda, conducted in partnership with joint venture (JV) partner Rio Tinto Mining and Exploration.
The first phase of drilling targeted two of twelve identified prospects—HCK-1 and HCK-2—where a total of 1,180 metres of core was drilled across four holes.
One of the standout results from the campaign was an intercept of 6.9 metres grading 2.11% lithium oxide (Li₂O) from a depth of 174 metres.
This included a higher-grade interval of 3.4 metres at 3.2% Li₂O between 174 and 178 metres down-hole.
Following the successful initial results, Rio Tinto has confirmed it will exercise its Stage 2 earn-in right, giving it a 51% ownership stake in the HCK licence.
Under the terms of the agreement, Rio Tinto can increase its interest to 75% by completing an additional $7.5 million in exploration work over the next three years.
Since the start of the JV in August 2023, Rio Tinto has already invested $4.7 million into the HCK project.
“We are very pleased with these initial drill results and with Rio Tinto’s decision to move forward with Stage 2 of the JV,” said Aterian CEO Simon Rollason.
“The drilling confirms the presence of spodumene-bearing lithium pegmatite, although at varying widths.”
Rollason added that the early-stage nature of the campaign—conducted as a reconnaissance or “scout” drilling program—means further work is necessary to determine the full scale and continuity of mineralization.
“There is significant potential to identify less-weathered zones where additional spodumene-rich pegmatites may exist,” he noted. “These early indicators provide a strong technical foundation for continued exploration.”
Aterian is set to receive a $100,000 cash payment from Rio Tinto at the start of Stage 2 drilling, which is expected to be announced before the end of 2025.
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