Appointment of ANSTO Minerals

Rainbow Rare Earths Limited

("Rainbow" or the "Company")

(LSE: RBW)

15 March 2021

Rainbow Appoints ANSTO Minerals to Advance Flow Sheet Optimisation at Phalaborwa

Rainbow Rare Earths Ltd is pleased to announce the appointment of ANSTO Minerals in Australia ("ANSTO") to advance the flow sheet process optimisation at the Company's Phalaborwa Rare Earths Project ("Phalaborwa") in South Africa.

·    ANSTO has world-leading expertise in the processing of critical and strategic minerals, including rare earths. With over 40 years' experience in providing practical solutions and innovative technology to industry, ANSTO's team of engineering, metallurgy, mineralogy, chemistry and geology experts is well-positioned to support Rainbow on this project.

·    ANSTO has been engaged to perform scouting leach tests on drill samples from Phalaborwa to confirm the metallurgical variability within the gypsum stacks.

·    Metallurgical test work will then be carried out to produce an optimised process flow sheet for the preliminary economic assessment ("PEA")/scoping study, based on the original Sasol bankable feasibility study-level flow sheet, which produced three tonnes of cerium depleted mixed rare earth carbonate directly from the gypsum.

·    Phalaborwa's flow sheet is expected to be significantly simpler than those required for other rare earths projects around the world, as the rare earths exist in a 'cracked' chemical form within the two gypsum stacks, obviating the need for the costly and capital-intensive stages of first producing a concentrate and then 'cracking' it prior to beneficiation.

George Bennett, CEO, said: "We are very excited to be working with one of the world's leading experts in rare earths flow sheets, alongside our own chemical and process engineers, Dave Dodd and Chris Le Roux, both of whom developed the flow sheets for the Lofdal and Peak Resources rare earth projects when they worked with me at MDM Engineering.  Following the completion of ANSTO's project, we will then publish a PEA/scoping study, which is expected to put us in a strong position to fast track the project at Phalaborwa.

With no requirement for waste stripping, hard-rock mining, significant crushing or milling and the capacity to progress straight to the downstream production of a mixed rare earth carbonate, due to the 'cracked' nature of the rare earths within the gypsum, which eliminates various processing stages that would normally be required in the production of a mixed rare earth carbonate, we believe Phalaborwa has the potential to be one of the lowest capital intensity projects in the world. As a result of the unique nature of this project, we anticipate that Phalaborwa can be brought into production far quicker than a traditional hard-rock rare earths mining project.

Positioned in an established mining town, with all the associated skilled labour availability and supporting industry in place, and on account of the existing infrastructure from the original Sasol Phosphoric Acid Plant, which remains on site and available for Rainbow to use, we believe Phalaborwa is optimally positioned to drive the Company's near-term development."

**ENDS**

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Notes to Editors:

Rainbow's strategy is to become a globally-significant producer of rare earth metals. NdPr are vital components of the strongest permanent magnets used for the motors and turbines driving the green technology revolution. Analysts are predicting demand for magnet rare earth oxides will grow substantially over the coming years, driven by increasing adoption of green technology, pushing the overall market for NdPr into deficit.

The Company's Gakara Project in Burundi, which produces one of the highest-grade concentrates in the world (typically 54% total rare earths oxides ("TREO")) through ongoing trial mining operations, is currently the only African producer of rare earths.  The Gakara basket is weighted heavily towards NdPr, which account for over approximately 19.5% of the contained TREO and 85% of the value of the concentrate.

The Phalaborwa Rare Earths Project, located in South Africa, comprises approximately 35 million tonnes of gypsum tailings stacked in unconsolidated dumps derived from historic phosphate hard rock mining, containing rare earth elements with an initial estimated average in situ grade of 0.5% TREO, based on previous sampling campaigns, of which +/- 30% comprises high-value NdPr. The rare earths are contained in chemical form in the gypsum dumps, which is expected to deliver a higher-value rare earth carbonate, with lower operating costs than a typical rare earth mineral project.