Australian lithium developer Ioneer announced new strategic partnerships with two South Korean engineering and infrastructure groups for its Rhyolite Ridge project in Nevada.

The move comes as conservation groups advance a legal challenge against the mine they say would threaten the survival of an endangered wildflower and fish endemic to Nevada.

On Tuesday Ioneer announced it signed non-binding letters of intent with Korea Overseas Infrastructure & Urban Development Corporation and Hyundai Engineering Co. to jointly develop the lithium project in Esmeralda County.

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The letters of intent are non-binding and do not create legally enforceable obligations, and there is no certainty that definitive agreements will be reached, Ioneer said on Tuesday. However, the groups plan to formalise their cooperation through memorandums of understanding in July 2026.

Ioneer was previously partnered with Sibanye-Stillwater, however, the South African miner scrapped its planned $490 million investment in the project, due in part to plummeting lithium prices.

The company is targeting a final investment decision in the second half of 2026, with first commercial production expected in 2029.

Once operational, the project is expected to produce 27,800 tons a year of lithium hydroxide and 135,500 tons a year of boric acid, with all processing conducted on site.

“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, Ioneer.

Rhyolite Ridge hosts the only known lithium-boron reserve in North America and is one of two globally, according to Ioneer. It is also the only project of its kind currently in development, the company said in a statement.

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The site is also home to Tiehm’s buckwheat, which grows on just 10 acres of lithium-boron rich soil near the Silver Peak Range in Esmeralda County. Once constructed, the mine would directly disturb about 191 acres of the wildflower’s federally protected critical habitat.

As a result, the project has faced legal challenges by conservation groups.

In 2024, the Center for Biological Diversity, Western Shoshone Defense Project, and the Great Basin Resource Watch sued the federal government over claims they failed to ensure the mine would not jeopardize the survival of the Tiehm’s buckwheat or adversely affect its critical habitat during the environmental review process.

In March, a federal judge ruled that the Interior Department properly approved Ioneer’s mine and sufficiently examined the impacts the project will have on Tiehm’s buckwheat, a rare wildflower whose entire population grows on just 10 acres of land.

Attorneys for conservation and Indigenous rights shot back and filed an appeal in April in the effort to stop an open-pit lithium-boron mine from being built on the only known habitat of an endangered wildflower.

“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, and we’re confident that our case before the 9th Circuit Court of Appeals will succeed.”