Economic Assessment for Uberaba Project in Brazil

Rainbow and Mosaic commence Economic Assessment for the recovery of Rare Earths from the Uberaba Project in Brazil

• The Economic Assessment ("EA") will be carried out as a joint collaboration with The Mosaic Company ("Mosaic"), the world's leading producers and marketers of concentrated phosphate and potash crop nutrients
• The EA will be based on an operation processing the phosphogypsum from the Mosaic Uberaba phosphoric acid ("phosacid") plant at a rate of ca. 4.3 million tonnes per annum ("Mtpa"), being twice the size of Rainbow's flagship Phalaborwa Project
• The preliminary process flowsheet to recover the rare earth elements ("REE") for the EA is based on in-house test work performed by Mosaic, with the support of Rainbow
• The EA will be based on average grades measured from samples taken from the Uberaba operation, which average 0.58% total rare earth oxides ("TREO") of which 24.5% represents high value neodymium and praseodymium oxides (together "Nd/Pr"), with economic quantities of dysprosium ("Dy") and terbium ("Tb")

NEWS RELEASE

Rainbow Rare Earths is pleased to announce that it has, along with Mosaic, approved the budget and commenced work on an EA for the recovery of rare earths from the Uberaba project in Brazil. The EA is intended to allow both parties to understand the economics ahead of considering a partnership to potentially replace the current non-binding MOU to realise this opportunity.

George Bennett, CEO of Rainbow, commented: "We are delighted to have made significant progress with the commencement of a formal EA of the Uberaba project, which reflects the strong collaboration between Rainbow and Mosaic under our MOU. I would like to thank Mosaic's very competent and professional team, who are working well with us on all aspects of the project, including sampling / mineralogy, the test work required to define the flowsheet and ongoing work to delineate the project feedstock.

Uberaba is an exciting project for Rainbow, given the technical similarities with Phalaborwa; however, it represents a significantly larger economic opportunity over the long-term due to the sheer scale of the planned annual feed rate and the long-term nature of the underlying phosphate deposit. As at Phalaborwa, we expect Uberaba to be a low-capital intensity project and a low-cost source of the critical rare earths driving the green energy transition and other advanced and emerging technologies."

Background to Uberaba

The Uberaba phosphogypsum contains valuable REE that occur as by-products of the phosacid production operations on site and Rainbow's pioneering IP can be applied to recover these REE.

The Uberaba material is similar in nature to Rainbow's Phalaborwa project in South Africa in that it is based on a hard rock carbonatite phosphate deposit, which is mined to initially produce a phosphate slurry feed that is then processed into phosacid using sulphuric acid. This process delivers phosphogypsum material that contains most of the REE present in the phosphate slurry feed.

Assay work on samples from the Mosaic phosphogypsum has returned grades of between 0.45% to 0.79% TREO, with Nd/Pr being 24.5% of the rare earths basket, plus economic quantities of Dy and Tb. The average grade, which will be used in the EA, is 0.58% TREO. The material has not been formally defined as a JORC compliant REE resource to date.

The Economic Assessment

The EA envisages an operation processing ca. 4.3 Mtpa of phosphogypsum in two ca. 2.15 Mtpa modules, which is around twice the annual size of Phalaborwa.

A flowsheet to recover the REE has been defined for the EA by test work as a joint collaboration between Rainbow and Mosaic. The flowsheet receives phosphogypsum from the Uberaba phosacid process facility and treats the material for REE extraction. The chemically processed and cleaned phosphogypsum stream is then returned to the Mosaic Uberaba process facility.

As at Phalaborwa, the EA is based on the establishment of a single hydrometallurgical plant on site, which will refine the material into separated rare earth oxides of +99% purity.

The EA will be based on an initial project life of 15 years. Due to the life of mine of the underlying phosphate resource feeding the phosacid plant at Uberaba, recovery of rare earths can be expected to extend for a far longer period. The modest third-party costs of ca. US$230k to develop the EA will be shared 50:50 between Rainbow and Mosaic.

For further information on Rainbow, please visit the Company's Curation Connect showcase at: Curation Connect - Rainbow Rare Earths Showcase or https://app.curationconnect.com/company/Rainbow-Rare-Earths-90903