Federal Lawsuit Looms as Ioneer Advances Rhyolite Ridge Lithium Project

Project Economics and Operational Advances

Ioneer Ltd has delivered a robust update on its Rhyolite Ridge Lithium-Boron Project in Nevada, revealing a 19% increase in the unlevered net present value (NPV) to US$2.237 billion. This improvement stems from a successful leach optimisation program that has shortened processing times and increased throughput, enabling a 9% rise in annual lithium hydroxide production to 27,800 tonnes and a 7% increase in boric acid output to 135,500 tonnes per annum.

The optimisation reduces the leach duration from three days to 1.5 days, allowing more ore to be processed with the same acid consumption, thus enhancing project economics without compromising recoveries significantly. This positions Rhyolite Ridge among the lowest cost lithium producers globally, with an all-in sustaining cash cost of US$4,628 per tonne of lithium carbonate equivalent.

Strategic Partnerships and Regulatory Landscape

Amid these technical gains, Ioneer is actively pursuing strategic partnerships to accelerate project development, with Goldman Sachs & Co. LLC advising on the process. The company expects to conclude these discussions in the first half of 2026, which will inform the timing of a final investment decision.

Rhyolite Ridge holds all significant federal and state permits, including a Record of Decision from the Bureau of Land Management and air and water permits from Nevada authorities. However, a federal lawsuit challenging the project’s environmental approvals is pending, with the court currently reviewing the merits. Ioneer has intervened alongside the federal government in defence of the project.

Market Dynamics and Sustainability Efforts

The lithium market showed strong momentum in late 2025, with spot prices for battery-grade lithium carbonate and hydroxide surging by over 40%, driven by supply shortfalls and robust demand from electric vehicle manufacturers. Boric acid demand also remained resilient, supported by growth in construction, electronics, and agriculture sectors, particularly in the Asia-Pacific region.

On the sustainability front, Ioneer continues its conservation efforts for Tiehm’s buckwheat, a rare plant species native to the project area, with expanded greenhouse facilities and ongoing collaboration with U.S. wildlife agencies. The company also maintains full compliance with environmental permits and reports no safety incidents during the quarter.

Corporate and Forward Outlook

Corporate governance changes include the appointment of a new interim CFO and company secretary, alongside a shift in the financial year to align with calendar years. Looking ahead, Ioneer plans to release an updated technical report incorporating the latest leach optimisation results in the first half of 2026 and aims to finalise its strategic partnership process within the same timeframe.

With a 77-year mine life fully supported by proven reserves and a flexible resource base, Rhyolite Ridge is poised to become a cornerstone supplier of critical minerals essential to the clean energy transition, particularly for the U.S. market seeking to reduce reliance on foreign sources.