Ioneer releases February 2025 Rhyolite Ridge lithium-boron mineral resource estimate

Ioneer Ltd has announced a 45 percent increase in the Mineral Resource estimate for the Rhyolite Ridge Lithium-Boron Project in Nevada, reflecting updated geological data from recent drilling campaigns. The revised estimate now stands at 510 million tons, containing 3.97 million tons of lithium carbonate equivalent (LCE) and 14.66 million tons of boric acid equivalent (BAE). Notably, 81 percent of the resource now falls within the measured and indicated categories, strengthening confidence in the project’s economic viability.

The updated resource estimate, based on twelve additional drill holes completed in 2024, underscores the project’s flexibility in lithium and boric acid production. The Rhyolite Ridge deposit consists of three distinct ore streams, allowing for production adjustments based on market conditions. Ioneer emphasizes that this unique mineral composition enables the company to prioritize higher-boron ore when lithium prices are lower, ensuring a steady revenue stream. The project is expected to derive 30-40 percent of its revenue from boron, with lithium contributing 60-70 percent.

The updated resource will serve as the foundation for an upcoming Ore Reserve estimate, slated for release in April 2025. This is expected to result in a substantial increase in reserves as a significant portion of previously classified inferred resources have been upgraded to measured and indicated status. The report also acknowledges ongoing environmental considerations, particularly regarding Tiehm’s buckwheat, a protected plant species located within the project area. While the mine plan has been approved by the Bureau of Land Management (BLM) with mitigation measures in place, future adjustments to the resource footprint may be required based on environmental assessments.

This latest update follows a broader trend of increased interest in lithium production within the U.S., particularly as the federal government supports domestic supply chains for critical minerals. Ioneer’s secured $996 million loan from the U.S. Department of Energy’s Loan Programs Office further highlights the project’s strategic importance. The company remains focused on advancing feasibility studies and optimizing extraction and processing methodologies to maximize the project’s economic potential.