Court upholds Ioneer (NASDAQ: IONR) Rhyolite Ridge permit, supporting lithium-boron project

Rhea-AI Filing Summary

Ioneer Ltd reports that the U.S. District Court for the District of Nevada has upheld federal approval of its Rhyolite Ridge Lithium-Boron Project mine plan, rejecting all legal challenges. The court confirmed that federal agencies complied with key U.S. environmental laws in their review.

The Nevada project aims to supply lithium and boron for batteries, permanent magnets, semiconductors, energy storage and defense uses, supporting a more secure U.S. supply chain. Ioneer describes the ruling as a significant milestone that lets it continue advancing toward construction and completing its strategic partnering process.

Ioneer is the 100% owner of Rhyolite Ridge, which previously secured a US$996 million loan from the U.S. Department of Energy’s Energy Dominance Financing Program in January 2025 and received its final federal permit from the Bureau of Land Management in October 2024. The company has offtake agreements with Ford, Prime Planet Energy & Solutions and EcoPro Innovation.

Positive

• Federal court upholds key permit: The U.S. District Court for the District of Nevada upheld approval of the Rhyolite Ridge mine plan, removing a major legal obstacle to developing Ioneer’s flagship lithium-boron project.
• Strong government and commercial backing: Rhyolite Ridge benefits from a US$996 million U.S. Department of Energy loan, a final federal permit from the Bureau of Land Management, and offtake agreements with Ford, Prime Planet Energy & Solutions and EcoPro Innovation.

Negative

• None.

Insights

Mining & project finance analyst

U.S. court backing removes a major permitting risk for Ioneer’s Rhyolite Ridge project.

The Nevada federal court’s decision to uphold the Rhyolite Ridge mine plan materially de-risks Ioneer’s flagship lithium-boron project. The ruling confirms that the Bureau of Land Management and U.S. Fish and Wildlife Service complied with core environmental statutes, reducing legal uncertainty around project approvals.

This legal validation comes on top of a US$996 million U.S. Department of Energy loan closed in January 2025 and the final federal permit received in October 2024. Together, these elements support financing and development prospects, though execution will still depend on completing the strategic partnering process and moving into construction as described.

Key Figures

DOE project loan: US$996 million

1 metrics

DOE project loan US$996 million Loan for Rhyolite Ridge from U.S. Department of Energy in January 2025

Key Terms

Endangered Species Act, National Environmental Policy Act, Energy Dominance Financing Program, offtake agreements, +1 more

5 terms

Endangered Species Act regulatory

"complied with the Endangered Species Act, Federal Land Policy and Management Act"

A law that protects species at risk of extinction and their habitats by restricting activities that could harm them, such as development, resource extraction, or land conversion. For investors, it matters because protected species or designated critical habitat can delay or block projects, add permit requirements and cleanup or mitigation costs, and create legal and regulatory risk—similar to safety rules that can pause or reshape a construction site if a protected animal is found.

National Environmental Policy Act regulatory

"and National Environmental Policy Act in their review and approval of the project"

A U.S. law that requires federal agencies to evaluate and disclose the likely environmental effects of major projects and decisions before they proceed. For investors, that review can delay approvals, add compliance costs, or change project plans—like a required safety inspection that can uncover problems or require fixes before construction continues—so NEPA processes are a key source of timing, cost and legal risk for projects involving federal permits or funding.

Energy Dominance Financing Program financial

"closed a US$996 million loan with the U.S. Department of Energy’s Energy Dominance Financing Program"

offtake agreements financial

"Ioneer signed separate offtake agreements with Ford Motor Company and Prime Planet Energy & Solutions"

An offtake agreement is a contract where a buyer agrees to purchase a set amount of a company's future production—such as minerals, energy, or manufactured goods—often before the product is made. For investors, these deals act like a guaranteed customer or advance order that reduces sales risk, helps secure project financing, and makes future revenue more predictable; think of it as a long-term subscription that stabilizes cash flow.

forward-looking statements regulatory

"This announcement contains certain forward-looking statements and comments about future events"

Forward-looking statements are predictions or plans that companies share about what they expect to happen in the future, like estimating sales or profits. They matter because they help investors understand a company's outlook, but since they are based on guesses and assumptions, they can sometimes be wrong.

Form 6-K: How Foreign Companies Report to the SEC →

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

Pursuant to Rule 13a-16 or 15d-16 of the

Securities Exchange Act of 1934

For the month of March 2026

Commission File Number: 001-41412

ioneer Ltd

(Translation of registrant’s name into English)

Suite 16.01, 213 Miller Street

North Sydney, NSW, 2060, Australia

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒    Form 40-F ☐

EXHIBIT INDEX

The following exhibits are filed as part of this Form 6-K:

Exhibit		Description
99.1		Press release dated March 31, 2026

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

	ioneer Ltd
	(registrant)
Date: March 31, 2026	By:	/s/ April Hashimoto
	Name: April Hashimoto
	Title:   Chief Financial Officer

Exhibit 99.1

 

U.S. District Court Upholds Federal Permit for Rhyolite Ridge Lithium-Boron Project

31 March 2026 – SYDNEY, Australia – Ioneer Ltd (“Ioneer”) (ASX: INR, NASDAQ: IONR) is pleased to announce that The U.S. District Court for the District of Nevada today issued its decision in Center for Biological Diversity v. Stone-Manning, upholding the approval of the Rhyolite Ridge mine plan.

The Rhyolite Ridge Lithium-Boron Project (Project) will mine and process two critical minerals in Nevada. The Project will provide a significant new source of two materials necessary for permanent magnets, batteries, semiconductors, behind-the-meter energy and military applications — strengthening the U.S. supply chain, reducing reliance on foreign sources, and bolstering national security.

The Court found that the Bureau of Land Management (BLM) and U.S. Fish and Wildlife Service (USFWS) complied with the Endangered Species Act, Federal Land Policy and Management Act, and National Environmental Policy Act in their review and approval of the project.

Ioneer issued the following statement:

“Ioneer is pleased that the District Court denied all challenges to the Rhyolite Ridge mine plan. For more than six years, we have worked closely with state, federal and tribal representatives, as well as the Fish Lake Valley community, to responsibly develop our Rhyolite Ridge Lithium-Boron Project.

This favorable outcome is a significant milestone and allows us to continue advancing our work in delivering lithium and boron for the United States.

Rhyolite Ridge will create hundreds of new American jobs, reduce reliance on foreign materials and processing, and provide a domestic source of two critical minerals.

We look forward to completing our strategic partnering process and beginning construction.”

Bernard Rowe, Ioneer Managing Director, added, “Today’s outcome is a credit to all involved parties in the thorough assessment and approval process. We look forward to bringing our long-term, low-cost and stable supply of lithium and boron online.”

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

—ENDS—

About Ioneer

Ioneer Ltd. is an emerging lithium–boron producer and the 100% owner of the Rhyolite Ridge Lithium-Boron Project. Rhyolite Ridge is one of only a small number of lithium-boron ore deposits globally and a linchpin project in Nevada’s burgeoning Lithium Loop.

Rhyolite Ridge closed a US$996 million loan with the U.S. Department of Energy’s Energy Dominance Financing Program in January 2025. In October 2024, Ioneer received the final federal permit for the project from the Bureau of Land Management, concluding the formal federal permitting process which began in early 2020. Ioneer signed separate offtake agreements with Ford Motor Company and Prime Planet Energy & Solutions (joint venture between Toyota and Panasonic) in 2022 and Korea’s EcoPro Innovation in 2021.

To learn more about Ioneer, visit www.Ioneer.com/investors or join our online communities on X, Facebook, LinkedIn, Instagram and YouTube.

Important Notice and Disclaimer

Forward-Looking Statement

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 forwardlooking 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.

Investor Relations

Chad Yeftich, Ioneer USA Corporation

Investor Relations

T: +1 775 993 8563

E: ir@ioneer.com

Media Relations

Daniel Francis, FGS Global

E: daniel.francis@fgsglobal.com

FAQ

What did the U.S. court decide about Ioneer (IONR) and the Rhyolite Ridge project?

The U.S. District Court for the District of Nevada upheld approval of Ioneer’s Rhyolite Ridge mine plan. The court found federal agencies complied with major environmental laws, removing a significant legal challenge to the project’s development path.

Why is the Rhyolite Ridge Lithium-Boron Project important for Ioneer (IONR)?

Rhyolite Ridge is Ioneer’s flagship project, supplying lithium and boron for batteries, permanent magnets, semiconductors and defense uses. It aims to bolster U.S. supply chains for critical minerals and provide a long-term, low-cost and stable source of these materials.

How does the court ruling affect permitting risk for Ioneer’s Rhyolite Ridge project?

The ruling significantly reduces permitting risk by confirming that prior approvals complied with the Endangered Species Act, Federal Land Policy and Management Act and National Environmental Policy Act. It lets Ioneer continue advancing toward construction under existing federal approvals.

What government financing support has Ioneer (IONR) secured for Rhyolite Ridge?

Rhyolite Ridge closed a US$996 million loan with the U.S. Department of Energy’s Energy Dominance Financing Program in January 2025. This large federal loan underpins project financing and reflects U.S. interest in securing domestic lithium and boron supplies.

Which customers have offtake agreements with Ioneer for Rhyolite Ridge production?

Ioneer has signed offtake agreements with Ford Motor Company, Prime Planet Energy & Solutions, a Toyota–Panasonic joint venture, and Korea’s EcoPro Innovation. These agreements support future demand for Rhyolite Ridge lithium and boron once production begins.

What are the next steps Ioneer (IONR) mentions after the court decision?

Ioneer states it looks forward to completing its strategic partnering process and beginning construction on Rhyolite Ridge. The company views the court’s decision as a significant milestone that allows continued advancement of project development activities in Nevada.

Filing Exhibits & Attachments

1 document

Press Releases

• EX-99.1 EXHIBIT 99.1 17.1 KB