ASX-listed Liontown Resources has started underground production stoping at the Kathleen Valley lithium operation in Western Australia, marking a key milestone as it transitions from openpit to underground mining.

The miner said the first blast at the Mt Mann orebody was fired on schedule, extracting about 1 500 t of ore. This is part of an initial stope designed to deliver about 12 000 t of ore — about two days’ worth of feed for the processing plant.

“The successful commencement of underground stoping at our Kathleen Valley lithium operation on schedule is a proud milestone for Liontown,” said MD and CEO Tony Ottaviano. 

“This achievement was made possible by advanced planning, the dedication of our team and the support from our mining partner, Byrnecut, ensuring the first stope blast at Mt Mann proceeded as planned.”

The Kathleen Valley operation is Australia’s first underground lithium mine. Liontown expects the method to deliver several advantages over openpit mining, including reduced ore dilution, improved lithia recoveries, and better ore fragmentation for more efficient processing.

During the March quarter, the company conducted underground ore processing trials using previously extracted development ore with a head grade of around 1.5% lithium oxide. These trials confirmed ore processability and delivered lithia recoveries above 70%.

“As part of normal preparations and planning, we undertook underground ore trials in the March quarter, in advance of first stoping, to understand the optimal plant performance settings,” said Ottaviano. 

“The trials delivered results in line with our study work, which reinforces our confidence in transitioning to full underground operations.”

The company is now focused on advancing the underground decline, opening additional working areas, and ramping up mining activity. Liontown aims for the mill to be supplied solely from underground ore and stockpiles by the fourth quarter of the 2026 financial year.

“This milestone further strengthens our foundations for long-term value creation and future shareholder returns,” Ottaviano said.