ioneer expects partner search to conclude in H1 2026

[Ben Graham]

ioneer (ASX: INR) (NASDAQ: IONR) now expects to complete its partner search for the Rhyolite Ridge lithium-boron mine project in Nevada during the first half of 2026, the company said in a year-end update Friday.

In July, the Australian mine developer launched a formal strategic partnering process after Sibanye-Stillwater (JSE: SSW)(NYSE: SBSW) pulled out of the project earlier in the year. At the time, ioneer said the partner search, which is being advised by Goldman Sachs, would take up to four months. However, the process has been dragged into the new year, which the company attributes to market and geopolitical factors.

In its latest update, ioneer said it remains confident that the coming year will mark a “transformational period” for the company, given Rhyolite Ridge’s status as a unique lithium-boron project that has been supported by the US government in the form of a $996 million loan.

Both lithium and boron are designated as critical minerals by the US Geological Survey. The latter was just recently included in the list due to its importance to national security as an input in advanced armor, high-strength magnets and nuclear shielding.

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Earlier this month, Bloomberg reported that ioneer is looking to become a major boron player by acquiring the US assets held by Rio Tinto (ASX, LSE: RIO), which could be valued as much as $2 billion.

Shares of ioneer gained by nearly double digits during Friday’s US trading session, trading at $4.61 apiece with a market capitalization of $306.8 million.

Advanced lithium-boron asset

The Rhyolite Ridge project, located 362 km north of Las Vegas, contains one of the largest lithium-boron resources in the US. With all permits in place and over 70% of its engineering design complete, it is also the most advanced lithium-boron project in the country.

ioneer has been working on the project since 2016, and drew in Sibanye-Stillwater as its partner in 2019. However, in February 2025, the South African miner walked away from its proposed $490 million investment for a 50% stake in the project.

For its next partner, ioneer plans to sell a smaller stake (40%) and has estimated a higher valuation for the project, according to a report earlier this year by the Financial Times. Prior to launching the partner search, the company had released an updated definitive feasibility study on Rhyolite Ridge that substantially improved the project economics, including a near quadrupling of its projected mine life (at 95 years) and a 20% increase in net present value (to $1.5 billion).

The new DFS, released in June, used an expanded ore reserve estimate that ioneer later confirmed at 7.8 million tonnes of boric acid and 2 million tonnes of lithium carbonate, which it said are enough to support an initial 77-year mine plan. On a lithium carbonate equivalent (LCE) basis, the project sits within the lowest cost quartile globally, supported by the co-production of boric acid, it added.

These improvements increased average annual lithium production for years 1-25 from 19,200 tonnes to 24,500 tonnes LCE, while boosting average annual boric acid production from 116,400 tonnes to 135,500 tonnes, the company said in its update.