Rhyolite Ridge’s Capital Costs Surge Amid 95-Year Mine Life Expansion

A Landmark Upgrade for Rhyolite Ridge

Ioneer Ltd has delivered a transformative update to its Rhyolite Ridge Lithium-Boron Project in Nevada, announcing a 308% increase in Ore Reserves to 246.6 million tonnes. This substantial upgrade translates to 1.92 million tonnes of lithium carbonate equivalent (LCE) and 7.68 million tonnes of boric acid equivalent (BAE), positioning Rhyolite Ridge as the world’s largest lithium-boron reserve.

With nearly half of the mineral resource now converted into reserves, the project’s mine life extends impressively to 95 years, a significant leap from the previous 26 years. This longevity underpins a stable, expandable operation that promises to be a cornerstone supplier of lithium and boron, two critical materials for the global transition to sustainable energy.

Economic Resilience Through Dual Commodities

What sets Rhyolite Ridge apart is its unique mineralogy, allowing simultaneous production of lithium and boric acid. Ioneer plans to prioritize high-boron ore in the first 25 years, producing approximately 19,200 tonnes per annum of LCE alongside 116,400 tonnes of boric acid. This co-product strategy is a savvy hedge against lithium price volatility, as boric acid markets remain stable and uncorrelated with lithium.

Financially, the project boasts compelling metrics – an after-tax net present value (NPV) of US$1.367 billion and an internal rate of return (IRR) of 14.5%. Operating costs are competitive, with an all-in sustaining cash cost of US$5,745 per tonne of LCE, placing Rhyolite Ridge in the lowest cost quartile globally. The boric acid credit further reduces net cash costs, enhancing economic resilience.

Capital and Operational Readiness

The capital expenditure estimate has risen to US$1.668 billion, reflecting updated engineering, inflation, and compliance with U.S. Department of Energy loan conditions. Approximately 70% of engineering is complete, with a Class 2 capital cost estimate providing a robust baseline for project execution. The project is fully permitted, including federal approval from the Bureau of Land Management, and has secured a US$996 million loan from the DOE Loan Programs Office.

Operational innovation is also a highlight, with plans to deploy autonomous haul trucks from the outset, enhancing safety and cost efficiency. The processing plant will utilize vat acid leaching technology, unique globally for lithium deposits, and produce technical-grade lithium carbonate initially, transitioning to battery-grade lithium hydroxide by year three.

Strategic Partnerships and Market Position

Ioneer has secured offtake agreements with industry heavyweights including Ford, Toyota-Panasonic joint venture Prime Planet Energy Solutions, and Korea’s EcoPro Innovation, ensuring a ready market for its lithium products. The boric acid product, meanwhile, taps into a stable global market dominated by few suppliers, offering a steady revenue stream that complements lithium sales.

Environmental stewardship is integral to the project, with measures in place to protect the endangered Tiehm’s buckwheat species and minimize ecological impact. The project’s location in Nevada, a mining-friendly and stable jurisdiction, further reduces geopolitical risks.