June 23 (Reuters) - Australian lithium miner Ioneer INR.AX said on Tuesday it has tied up with Korea Overseas Infrastructure & Urban Development and Hyundai Engineering 000720.KS to support the development of its Rhyolite Ridge project in Nevada.

Shares of Ioneer rose 12.5% to A$0.158, their highest since May 15, while the broader benchmark index .AXJO was up 0.3%, as of 0004 GMT.

Here are some details:

• 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 lithium-boron producer said in a statement.

• Ioneer, Korea Overseas Infrastructure & Urban Development and Hyundai Engineering plan to formalise their cooperation through memorandums of understanding in July 2026, the Australian company said.

• Ioneer said the agreements would strengthen its relationship with South Korea, following its 2021 supply agreement with EcoPro Innovation.

• 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.

• Ioneer has invested more than $220 million in the project since 2016 and has completed over 70% of its advanced engineering work.

• 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 metric tons per year of lithium hydroxide and 135,500 tons per year of boric acid, with all processing conducted on site.