Ioneer project to meet rising demand for U.S. electric vehicle components while creating dedicated space to protect biological diversity

April 25, 2023 – RENO, Nevada – Today Ioneer Ltd (ASX: INR, NASDAQ: IONR) released new findings showing a 168% increase of lithium within its Rhyolite Ridge Lithium-Boron project. The Nevada site is now estimated to hold enough lithium carbonate, a critical material in electric vehicle battery production, to power upward of 50 million electric vehicles with further expansion potential pending additional exploration.

In the coming years, U.S. demand for lithium is expected to soar to keep pace with projected demand for EVs. The updated estimate underscores Rhoylite Ridge’s potential in strengthening U.S. supply chains and securing a domestic and environmentally sustainable source of lithium and boron. Because its world-class processing facility will be on-site at Rhyolite Ridge, Ioneer can more quickly produce and efficiently deliver lithium to U.S. battery manufacturers. The innovative process eliminates the need to transfer the material to a separate plant for refining and will allow Ioneer to maximize the lithium’s full potency.

“Rhyolite Ridge is a once in a generation opportunity to produce a critical and reliable source of lithium and boron for the U.S. electric vehicle supply chain. Our best-in-class operations will provide desperately needed domestic materials, create jobs and reduce emissions,” said James Calaway, the executive chairman of Ioneer. “We look forward to completing the important federal permitting process and getting to work.”

“Today’s Mineral Resource Update demonstrates Ioneer’s unique ability to supply secure and strategic materials for electric vehicle battery manufacturers,” said Bernard Rowe, the managing director of Ioneer. “These new findings demonstrate how Ioneer can help the United States sustainably source lithium and boron while combatting climate change. Ioneer looks forward to finalizing the remaining federal requirements and commencing our operations.”

Once federal permitting and construction is complete, Rhyolite Ridge is expected to quadruple current U.S. lithium chemical output. The updated report, conducted by WSP USA Inc, (formerly Golder Associates USA Inc.), now estimates Rhyolite Ridge’s Mineral Resource deposit at 360.0 million tonnes – containing 3.4 million tonnes of lithium carbonate equivalent and 14.1 million tonnes of boric acid equivalent. That reflects a 168% increase in lithium carbonate and 18% increase in boric acid (collectively a 145% increase in mineralized resource) from an April 2020 Ioneer Mineral Resource statement. It also builds on the company’s Definitive Feasibility Study, which confirmed Rhyolite Ridge as a world-class lithium and boron project that is expected to become a globally significant, long-life, low-cost source of lithium and boron.

The Department of Energy’s Loan Program Office previously estimated that Rhyolite Ridge could reduce annual domestic gas consumption by nearly 145 million gallons and prevent the release of 1.29 million tonnes of carbon dioxide each year from gas cars. The DOE estimates relied upon the April 2020 findings, and the revised estimates are expected to push those environmental benefits higher.

Today’s resource estimate strengthens the mine plan being permitted by Bureau of Land Management (BLM) that avoids all Tiehm’s buckwheat, a plant classified as an endangered species by the United States Fish and Wildlife Service.  Ioneer has also made revisions to include measures to minimize and mitigate for potential indirect impacts within the designated critical habitat areas identified.  Prior to its formal federal protection, Ioneer contributed more than $1 million to ensure the plant’s long-term growth and success and has budgeted an additional $1 million annually to protect the species.

The Project’s Mine Plan of Operations, submitted to the BLM in July 2022, is currently under NEPA review.

To read the full report, please click here.

This ASX release has been authorized by Ioneer Managing Director Bernard Rowe.

–ENDS–

Chad Yeftich
Ioneer USA
Investor & Media Relations
T: +1 775 993 8563
E: ir@ioneer.com

Jason Mack
Ioneer Limited
Investor Relations (AUS)
T: +61 410 611 709
E: jmack@ioneer.com

Competent Persons Statement

The information in this report that relates to the March 2023 Mineral Resource estimate is based
on information compiled by Jerry DeWolfe, a Competent Person who is a Professional Geologist
(P.Geo.) with the Association of Professional Engineers and Geoscientists of Alberta (APEGA), a
“Recognized Professional Organisation” included in a list promulgated by ASX from time to time. Mr
DeWolfe is a full-time employee of WSP Canada Inc. (WSP, formerly Golder) and is independent of
Ioneer and its affiliates. Mr DeWolfe has sufficient experience that is relevant to the style of
mineralisation and type of deposit under consideration and to the activity being undertaken to
qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting
of Exploration Results, Mineral Resources and Ore Reserves’ (JORC Code 2012). Mr DeWolfe
consents to the inclusion in the report of the matters based on his information in the form and
context in which it appears.

The information in this report that relates to the 2020 Ore Reserve estimate is based on information
compiled by Terry Kremmel, a Competent Person who is a certified Professional Engineer (‘PE’) in
the US and a Registered Member of the Society for Mining, Metallurgy, & Exploration (‘SME’), a
“Recognized Professional Organisation” included in a list promulgated by ASX from time to time. Mr
Kremmel is a full-time employee of WSP USA Inc. (WSP, formerly Golder) and is independent of
Ioneer and its affiliates. Mr Kremmel has sufficient experience that is relevant to the style of
mineralisation and type of deposit under consideration and to the activity being undertaken to
qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting
of Exploration Results, Mineral Resources and Ore Reserves’ (JORC Code 2012). Mr Kremmel
consents to the inclusion in the report of the matters based on his information in the form and
context in which it appears.

About ioneer

Ioneer Ltd is the 100% owner of the Rhyolite Ridge Lithium-Boron Project located in Nevada, USA, the only known lithium-boron deposit in North America and one of only two known such deposits in the world. The Definitive Feasibility Study (DFS) completed in 2020 confirmed Rhyolite Ridge as a world class lithium and boron project that is expected to become a globally significant, long-life, low-cost source of lithium and boron vital to a sustainable future. In September 2021, Ioneer entered into an agreement with Sibanye-Stillwater where, following the satisfaction of conditions precedent, Sibanye Stillwater will acquire a 50% interest in the Project, with Ioneer maintaining a 50% interest and retaining the operational management responsibility for the joint venture. In January 2023, Ioneer received a conditional commitment from the U.S. Department of Energy Loan Programs Office for up to $700 million of debt financing. Ioneer signed separate offtake agreements with Ford Motor Company and PPES (joint venture between Toyota and Panasonic) in 2022 and Korea’s EcoPro Innovation in 2021.

Forward-looking statements

This announcement contains certain forward-looking statements and comments about future events,
including Ioneer’s expectations about the Project and the performance of its businesses. Forward
looking statements can generally be identified by the use of forward-looking words such as ‘expect’,
‘anticipate’, ‘likely’, ‘intend’, ‘should’, ‘could’, ‘may’, ‘predict’, ‘plan’, ‘propose’, ‘will’, ‘believe’,
‘forecast’, ‘estimate’, ‘target’ and other similar expressions within the meaning of securities laws of
applicable jurisdictions. Indications of, and guidance on, the Conditional Commitment, financing plans,
future earnings or financial position or performance are also forward-looking statements.
Forward-looking statements involve inherent risks and uncertainties, both general and specific, and
there is a risk that such predictions, forecasts, projections and other forward-looking statements will
not be achieved. Forward-looking statements are provided as a general guide only and should not be
relied on as an indication or guarantee of future performance. Forward looking statements involve
known and unknown risks, uncertainty and other factors which can cause Ioneer’s actual results to
differ materially from the plans, objectives, expectations, estimates, and intentions expressed in such
forward-looking statements and many of these factors are outside the control of Ioneer. Such risks
include, among others, uncertainties related to the finalisation, execution, and funding of the DOE
financing, including our ability to successfully negotiate definitive agreements and to satisfy any
funding conditions, as well as other uncertainties and risk factors set out in filings made from time to
time with the U.S. Securities and Exchange Commission and the Australian Securities Exchange. As
such, undue reliance should not be placed on any forward-looking statement. Past performance is not
necessarily a guide to future performance and no representation or warranty is made by any person
as to the likelihood of achievement or reasonableness of any forward-looking statements, forecast
financial information or other forecast. Nothing contained in this announcement, nor any information
made available to you is, or shall be relied upon as, a promise, representation, warranty or guarantee
as to the past, present or the future performance of Ioneer.

Except as required by law or the ASX Listing Rules, Ioneer assumes no obligation to provide any
additional or updated information or to update any forward-looking statements, whether as a result
of new information, future events or results, or otherwise.