Ioneer leach tests confirm growth potential of Rhyolite Ridge lithium-boron project

Findings from leach tests conducted on Type 3 mineralisation from the Rhyolite Ridge lithium-boron project in the US have demonstrated organic growth potential for owner ioneer (ASX: INR).

Latest results show the low-boron, low-clay mineralisation shares similar characteristics to the project’s high-boron Type 1 mineralisation, with leach recoveries of 89% to 94% and free draining characteristics.

The findings build upon a mineral resource estimate released in April for the South Basin deposit of 3.4 million tonnes of lithium carbonate equivalent.

They provide an update to Ioneer’s 2020 definitive feasibility study, which focused exclusively on Type 1.

The results are believed to have “far exceeded” the company’s expectations.

Heap or vat leaching

Testing confirmed Type 3 and North Basin mineralisation as candidates for heap or vat leaching methods similar to those employed for processing Type 1 mineralisation.

Ioneer said approximately 79% of the 360Mt global resource can now be processed in a similar manner to Type 1 mineralisation to create critical electric vehicle battery materials within the project’s existing footprint.

The findings position the company to quadruple US lithium production by 2026 and to substantially increase supply over time.

They support previous estimates which indicated the project could contain sufficient lithium to power over 50 million electric vehicles.

Growing demand

Managing director Bernard Rowe said the potential to increase the lithium and boron produced and refined at Rhyolite Ridge comes at a time of growing demand for US domestic supply.

“These results reinforce this project’s unique mineralogy and our ability to deliver these urgently-needed battery materials within the existing footprint of our proposed mine site,” he said.

“We look forward to completing the important federal permitting process, delivering these critical and valuable materials, and strengthening domestic electric vehicle supply chains.”

Increasing current supply

Once operational, Rhyolite Ridge is expected to quadruple the current US supply of lithium and help rebalance the global production of boric acid.

Stage 1 construction will be funded through a combination of conditional commitments including approximately $764 million equity from joint venture partner Sibanye-Stillwater and $1 billion in debt from the US Department of Energy’s Loan Programs Office.

Lithium production is expected to follow in 2026.