Rainbow Rare Earths Regulatory News (RBW)

7 September 2023

Rainbow Rare Earths Limited

("Rainbow" or "the Company")

LSE: RBW

Initial Results from Uberaba phosphogypsum stack confirms Rare Earths Opportunity

Rainbow Rare Earths is pleased to announce the assay results of the samples from the Uberaba phosphogypsum stack in Brazil that is the subject of the recently announced memorandum of understanding ("MOU") between Rainbow and The Mosaic Company ("Mosaic").

Highlights

· Initial assay analysis from samples indicates an average grade of 0.58% total rare earth oxides ("TREO"), higher than the 0.44% TREO for the Phalaborwa project.

· The Uberaba basket contains all four of the most economically important rare earths, Neodymium and Praseodymium ("NdPr"), Dysprosium ("Dy") and Terbium ("Tb"), with NdPr representing ca. 25% of the basket; NdPr represents ca. 29% of the basket at Phalaborwa.

Rainbow assayed gypsum samples from different areas of the Mosaic stack, which were sent to SGS Laboratories ("SGS") in Toronto for testing. These initial results, considered positive, confirm that the Uberaba phosphogypsum stack has similar characteristics to Phalaborwa given that both stacks are based upon a hard rock carbonatite phosphate deposit.

Rainbow is encouraged by these results and is therefore planning additional test work at SGS around the mineralogy to identify the rare earth phases and facilitate the development of a process test programme.

Following the development of the process flowsheet, the next step entails producing a preliminary economic assessment of this opportunity to extract rare earths.

George Bennett, CEO of Rainbow, commented: "These positive initial assay results confirm that Uberaba represents a major opportunity for Rainbow to be able to develop an economic project along the lines of Phalaborwa, due to the similar nature of both gypsum resources. The Uberaba phosphogypsum stack is expected to be considerably larger in size than Phalaborwa and it is exciting that initial results indicate it could have a higher rare earth basket price, due to the higher NdPr content. We expect that a significant portion of the process flowsheet and intellectual property developed for Phalaborwa can be applied to rare earth extraction at Uberaba."

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Notes to Editors:

About Rainbow:

Rainbow Rare Earths aims to be a forerunner in the establishment of an independent and ethical supply chain of the rare earth elements that are driving the green energy transition. It is doing this successfully via the identification and development of secondary rare earth deposits that can be brought into production quicker and at a lower cost than traditional hard rock mining projects, with a focus on the permanent magnet rare earth elements neodymium and praseodymium, dysprosium and terbium.

The Company is focused on the development of the Phalaborwa Rare Earths Project in South Africa and the earlier stage Uberaba Project in Brazil. Both projects entail the recovery of rare earths from phosphogypsum stacks that occur as the by-product of phosphoric acid production, with the original source rock for both deposits being a hardrock carbonatite. Rainbow will use a proprietary separation technique developed by and in conjunction with its partner K-Technologies, Inc., which simplifies the process of producing separated rare earth oxides (versus traditional solvent extraction), leading to cost benefits, as well as being more environmentally friendly.

The Phalaborwa Preliminary Economic Assessment has confirmed strong base line economics for the project, which has a base case NPV10 of US$627 million[1], an average EBITDA operating margin of 75% and a payback period of < two years. Pilot plant operations commenced in 2023, with the project expected to reach commercial production in 2026, just five years after work began on the project by Rainbow.

More information on the company is available at www.rainbowrareearths.com.