Hyundai backs ioneer’s Nevada lithium‑boron project: capex, schedule and output lens
Reviewed by Tom Sullivan

First reported on MINING.com
30 Second Briefing
Hyundai Engineering and Korea Overseas Infrastructure & Urban Development are set to sign MoUs in July 2026 to support ioneer’s Rhyolite Ridge lithium‑boron project in Nevada, which targets first production by 2029. The A$461.2 million ASX‑listed developer has already completed over 70% of advanced engineering and invested more than $220 million since 2016 on what it says is North America’s only known lithium‑boron reserve. Planned on-site processing is designed to deliver 27,800 t/y of lithium hydroxide and 135,500 t/y of boric acid, positioning the project for a final investment decision in H2 2026.
Technical Brief
- Hyundai Engineering and Korea Overseas Infrastructure & Urban Development will formalise cooperation via MoUs in July 2026.
- Sibanye-Stillwater previously proposed a $490 million investment for a 50% project stake before exiting in February 2025.
- Ioneer’s market capitalisation reached A$461.2 million after the announcement, with shares peaking 29% intraday.
- More than $220 million has already been sunk into Rhyolite Ridge since 2016, largely on engineering and studies.
- Rhyolite Ridge is described by ioneer as North America’s only known lithium‑boron reserve and one of two globally.
- On-site flowsheet is configured for dual production of lithium hydroxide and boric acid rather than concentrate export.
Our Take
The related May 2026 piece on Amnesty International’s criticism of Nevada lithium projects signals that Rhyolite Ridge’s lithium-boron output will likely face sustained ESG and permitting scrutiny, which Hyundai Engineering and KIND will need to factor into their 2026 final investment decision timeline.
In our database of Mining ‘Projects’ coverage, Nevada lithium assets like Rhyolite Ridge and Thacker Pass are among the few US projects repeatedly framed as strategic for non-Chinese battery supply, so Korean involvement here strengthens South Korea’s attempt to diversify lithium hydroxide sourcing away from China-linked supply chains.
With ioneer’s market capitalisation around US$320 million and a proposed 50% stake in Rhyolite Ridge, the project-level exposure is large relative to the corporate balance sheet, making the participation of state-backed Korea Overseas Infrastructure & Urban Development particularly important for de-risking financing and EPC execution for this lithium-boron development in Nevada.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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