Name of the Project
Rhyolite Ridge lithium/boron project.

Location
Nevada, US.

Project Owner/s
Emerging miner ioneer.

Project Description
The project is one of the few known lithium–boron deposits globally and is considered a cornerstone development within Nevada’s emerging “Lithium Loop”.

Rhyolite Ridge ore reserves more than quadrupled from 60-million tonnes in 2020 to 247-million tonnes in June 2025, delivering a mine life of 95 years. The project will produce at least three saleable chemical products – lithium carbonate, lithium hydroxide monohydrate and boric acid.

The ore reserve contains a total of 1.92-million tonnes of lithium carbonate equivalent (LCE) and 7.68-million tonnes of boric acid equivalent, underpinning plans for a large, long-life, low-cost expandable operation, producing lithium carbonate, boric acid and then battery-grade lithium hydroxide.

The mine plan comprises almost entirely reserve material, with nearly 50% of that being proven ore reserves.

Rhyolite Ridge ore will be processed by vat acid leaching, impurity removal, evaporation, and crystallisation, following a flowsheet developed for this project using known and commercially proven equipment and technology.

By prioritising high boron ore in the first 25 years of production, the project is poised to produce an average of 19 200 t/y of LCE and 116 400 t/y of boric acid.

The resource remains open in three directions, allowing for a potential extension to the life-of-mine.

Potential Job Creation
About 400 to 500 jobs are expected to be created during construction and 250 to 300 jobs during operations.

Net Present Value/Internal Rate of Return
The project has compelling economics with an after-tax net present value of $1.37-billion, and an unlevered, after-tax internal rate of return of 14.5%.

Capital Expenditure
Total capital expenditure to complete the project is estimated at $1.67-billion, including a 10% contingency.

Planned Start/End Date
First production is expected within 36 months of a final investment decision.

Latest Developments
ioneer has secured a key legal victory after a US federal court upheld approvals for the project.

The company reported on March 31 that US District Court for the District of Nevada had dismissed all challenges in the case: Center for Biological Diversity v. Stone-Manning, confirming that the Bureau of Land Management and the US Fish and Wildlife Service had complied with key environmental and land-use legislation in approving the project.

The ruling found that the agencies met requirements under the Endangered Species Act, National Environmental Policy Act, and Federal Land Policy and Management Act.

ioneer has said the decision is a milestone for the project, noting that the project will support US efforts to strengthen domestic supply chains and reduce reliance on foreign sources.

MD Bernard Rowe has said the outcome reflects the extensive review and permitting process undertaken over several years; ioneer worked for more than six years with federal, state and tribal stakeholders, as well as the local Fish Lake Valley community, to advance the project responsibly.

The company secured a $996-million loan from the US Department of Energy in January last year and received its final federal permit in October 2024, concluding a permitting process that began in 2020. The company has also signed offtake agreements with major industry players, including Ford Motor Company, Prime Planet Energy & Solutions, and EcoPro Innovation.

Key Contracts, Suppliers and Consultants
Fluor (definitive feasibility study).

Contact Details for Project Information
ioneer, tel +61 2 9922 5800 or email ir@ioneer.com.