ASX-listed Core Lithium has delivered an upgraded ore reserve and optimised mine plan for the Grants deposit at its 100%-owned Finniss lithium project in the Northern Territory, reducing pre-production capital requirements by up to A$45-million and bringing forward first ore production.

Under the updated plan, Grants will now be initially mined as an openpit before transitioning to underground operations, allowing first ore within a month of mobilisation. The company said the approach would defer underground infrastructure costs while accelerating revenue generation.

The revised plan has also resulted in a 33% increase in the Grants ore reserve to 1.53-million tonnes at 1.42% lithium oxide (Li₂O), representing a 44% increase in contained lithium oxide metal.

Core CEO Paul Brown said the changes delivered a more robust operating profile for the Finniss restart. “The updated ore reserve for Grants delivers clear benefits - continuing as an openpit (transitioning to underground later) brings first ore within one month of mobilisation, brings revenue forward, and reduces Grants preproduction capital by $35-million to $45-million through deferral of underground infrastructure,” Brown said.

“The Grants ore reserve has increased by 33% to 1.53-million tonnes at 1.42% Li₂O, lifting contained Li₂O by 44%. Collectively, these changes lower capital intensity, support the ongoing strategic funding process, and strengthen Finniss as a compelling restart with a robust, independently supported operating plan.”

The optimised mine design follows updated geotechnical assessments that identified opportunities to safely deepen the existing pit to access an additional 740 000 t of ore. The company said this would enable a smoother transition to underground mining at a later stage while maintaining a compact footprint.

Located 88 km by road from the Darwin Port, Finniss remains one of Australia’s closest lithium projects to export infrastructure. The updated plan supports Core Lithium’s ongoing strategic funding process aimed at restarting production amid growing global demand for lithium used in electric vehicle batteries.