Rhyolite Ridge lithium-boron project has a new investor

Rhyolite Ridge has found a new investor: an institution of the South Korean government.

Rhyolite Ridge lithium-boron project from Australian company Ioneer Limited has signed strategic non-binding letters of intent with the Korea Overseas Infrastructure & Urban Development Corp. and Hyundai Engineering Co. Ltd., according to an announcement.

The Korea Overseas Infrastructure & Urban Development Corporation is a public institution of the Republic of Korea, mandated by its Ministry of Land, Infrastructure and Transport to “facilitate and invest in overseas infrastructure and public-private partnership projects,” the press release said.

Hyundai Engineering is a Korean and international engineering, procurement and construction company, which will “advance the development” of the Rhyolite Ridge project.

“Rhyolite Ridge has been a decade in the making — through ongoing partnerships, permitting, and financing. Working with trusted Korean partners with a track record of on-time and on-budget delivery brings us closer to breaking ground and delivering urgently needed lithium and boron,” said Bernard Rowe, managing director at Ioneer. “We’re delighted to work with KIND and Hyundai Engineering and look forward to what we’ll accomplish together.”

Ioneer said in a news release that currently the LOIs are “non-binding and do not create legally enforceable obligations” for KIND and Hyundai Engineering

“There can be no certainty that legally binding arrangements will be entered into,” said Ioneer in the news release.

Formal memorandums of understanding are expected by July.

Once operational, the mine will create around 300 permanent on-site positions and will produce 27,800 tonnes of lithium hydroxide and 135,500 tonnes of boric acid annually.

This news comes after South African precious metals mining company Sibanye-Stillwater, the mine’s largest investor, pulled out of the project in February 2025. Sibanye-Stillwater had plans to invest $490 million into the project for a 50 percent ownership stake. The decision to pull out came after the price of lithium plunged by around 80 percent at the time, after its peak in 2022.

Rhyolite Ridge is one of two known lithium-boron reserves globally and the only one in North America. Once operational, it will quadruple the nation’s current domestic lithium supply.

In January 2025, Ioneer received a $996 million loan from the Department of Energy through its Loan Programs Office under the Advanced Technology Vehicles Manufacturing program to support on-site processing of lithium-boron at its Rhyolite Ridge Lithium-Boron Project in Esmeralda County, according to a news release from the company.

Multiple concerns have been raised about the Rhyolite Ridge mine, saying the mine will drive the extinction of the endangered rare wildflower Tiehm’s buckwheat and destroy indigenous peoples sacred lands.

“Rhyolite Ridge Mine was approved through a permitting process riddled with errors and omissions and stacked in favor of the thousand-foot-deep open-pit mine,” said Patrick Donnelly, Great Basin director at the Center for Biological Diversity. “Independent scientists agree that the mine will drive Tiehm’s buckwheat to extinction.”

In April, the nonprofit Center for Biological Diversity, which is headquartered in Tuscon, Arizona, filed an appeal in the 9th Circuit Court of Appeals. The appeal is an attempt to overturn a federal court ruling that upheld the approval of the mine, which the environmental group said would drive the rare wildflower to extinction.