Rainbow Rare Earths moves Uberaba project into pre-feasibility

Rainbow Rare Earths Ltd (LSE:RBW, OTC:RBWRF, FRA:RR1) has moved its Uberaba project in Brazil into pre-feasibility work alongside The Mosaic Company, with the study targeting completion in the second half of 2027 and SRK Consulting appointed to prepare its maiden JORC-compliant resource estimate. The PFS will assess an on-site processing plant capable of treating around 2.7 million tonnes of phosphogypsum waste a year over an initial 30-year project life. The project was originally modelled at a head grade of roughly 5,100 parts per million total rare earth oxides, with scope for a longer operating life given the underlying phosphate feedstock. Mosaic is also shipping around six tonnes of phosphogypsum to Rainbow’s laboratory and pilot plant in South Africa for further test work. Rainbow said its flowsheet builds on proprietary processing technology developed for the Phalaborwa project and is designed to produce separated neodymium-praseodymium oxide and an SEG+ mixed rare earth carbonate at 99.5% purity. Uberaba’s March economic assessment estimated a post-tax NPV10 of US$916 million and a 45% post-tax internal rate of return, alongside average annual EBITDA of US$217 million over 30 years and a 1.7-year payback period. Those figures used spot rare earth pricing reported by Argus Media in March 2026. Chief executive George Bennett said Uberaba was expected to demonstrate the potential to apply Rainbow’s proprietary technology across other phosphogypsum projects.