Hyundai backs ioneer’s Nevada lithium-boron project

Shares in Australian lithium developer ioneer (ASX: INR) gained this week after securing support from two South Korean engineering and infrastructure groups for its Rhyolite Ridge project in Nevada, a key U.S. source of battery materials targeting production by 2029.

Ioneer said Korea Overseas Infrastructure & Urban Development and Hyundai Engineering plan to formalize their cooperation through memorandums of understanding next month. The agreements build on South Korean ties, which include a supply agreement signed with EcoPro Innovation in 2021, and add international heft to one of North America’s most strategically significant lithium projects in the quest to replace Chinese supplies of the metal. 

“Securing domestic critical minerals is an economic imperative,” executive chairman James Calaway said. “We are now one step closer to a final investment decision and the construction of this once-in-a-generation asset for US critical minerals production.”

Shares in Ionner climbed to A18¢ intraday on Tuesday from A¢14 on Friday before closing at A$0.16 on Wednesday in Sydney, its highest level since May 13, giving the company a market capitalization of nearly A$477 million (US$329 million). 

10 years 

Ioneer has been working on Rhyolite Ridge since 2016 and brought in Sibanye-Stillwater (JSE: SSW; NYSE: SBSW) as a partner in 2019. However, the South African miner walked away in February 2025 from a proposed $490-million investment for a 50% stake in the project.

Rhyolite Ridge hosts the continent’s only known lithium-boron reserve and is one of only two such deposits globally, according to Ioneer. The company has invested more than $220 million in the project since 2016 and completed more than 70% of its advanced engineering work. It’s s targeting a final investment decision in the second half of 2026.

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