Rhyolite Ridge hosts the largest undeveloped boron Ore Reserve in the world outside of Türkiye. The project, located in Esmeralda County, Nevada, is fully permitted and shovel ready. The latest Ore Reserve published on 29 October 2025 contains 7.76 million tonnes of Boric Acid and 2.04 million tonnes of Lithium Carbonate.

 

 

The expansion of the U.S. Geological Survey's critical mineral list to include boron reaffirms the federal government’s commitment to expanding secure, U.S.-based sources of these essential materials, directly benefiting Rhyolite Ridge and other domestic projects. Per the USGS, the list of critical minerals informs U.S. supply chain risk mitigation, federal policy and strategy, stockpiles, permitting processes, scenario planning and private investment. Through the public comment process, representatives of the boron industry provided additional information, specifically that the U.S. does not manufacture enough of certain specialized boron-based products needed for national security and technology applications to meet its domestic needs, relying instead on imports from China and other countries.

 

 

This designation will enhance the Rhyolite Ridge Project’s visibility within U.S. policy discussions because of its ability to provide the domestic mining and processing of not only one, but two critical minerals.

 

 

Boron has long been recognized as essential to national security and energy dominance in the United States by the Department of War because boron ceramics (i.e., boron carbide) are essential for military applications, including advanced armour, high-strength magnets, and nuclear shielding. Formally recognizing the indispensable role boron plays in defence and energy systems through its inclusion on the critical mineral list will raise the Rhyolite Ridge Project’s strategic profile at the federal level within the United States.

 

 

The Rhyolite Ridge Lithium-Boron Project has already benefited from federal investment (i.e., $996 million loan guarantee from the Department of Energy Loan Programs Office) for the processing of the Project’s lithium. The designation of boron as a critical mineral will improve the Project's access to additional federal support aimed at securing domestic downstream processing for critical mineral supply chains.

 

 

The critical mineral designation of boron can help lead to policies that support and de-risk the Rhyolite Ridge Project for private sector investors by embedding boron within national resilience strategies and domestic sourcing initiatives. This is significant for Rhyolite Ridge because, among other reasons, the co-production of boric acid and lithium using a single mining and processing flowsheet already results in a globally low-cost position for lithium.

 

 

This designation will also benefit Rhyolite Ridge because industries in the private sector that utilize boron will be incentivized to secure domestic sources of boron. Rhyolite Ridge offers a valuable source of boron for the United States that will be processed onsite into a purified product (i.e., boric acid) that can be used for downstream processing of domestic boron ceramics and other important materials.

 

 

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