Rainbow and Mosaic Advance Uberaba Rare Earths Project
Rainbow Rare Earths and Mosaic have initiated the prefeasibility study for the Uberaba rare earths project in Brazil, targeting a 2030 start date.
Rainbow Rare Earths and Mosaic have commenced the prefeasibility study for the Uberaba rare earth elements project in Minas Gerais, Brazil. The initiative leverages Mosaic’s existing phosphate operations to recover light and heavy rare earths from phosphogypsum, a byproduct of phosphoric acid production.
Under the proposed joint venture structure, Mosaic holds a 51% stake while Rainbow retains 49%, contingent upon positive study outcomes and final agreements. The project aims to establish an on-site processing facility with an annual throughput of 2.7 million tonnes, designed to operate over a 30-year mine life.
Financial Metrics Define Project Viability
The preliminary economic assessment projects an after-tax net present value of $916 million at a 10% discount rate, with an internal rate of return of 45%. Capital expenditure is estimated at $279 million, leading to a rapid payback period of 1.7 years in the base case scenario.
Sensitivity analysis indicates the project remains robust under higher discount rates, maintaining an after-tax NPV of $609 million at 13.5%. These figures underscore the financial appeal of extracting high-purity rare earths from existing industrial waste streams.
Operational Focus On High Purity Outputs
The processing plant will produce separated neodymium and praseodymium oxide, alongside a samarium, europium, and gadolinium plus product. All targeted outputs are designed to achieve purities exceeding 99.5%, meeting stringent industrial standards for battery and magnet applications.
The process is circular by design, with the cleaned phosphogypsum stream intended for return to Mosaic’s Uberaba facility. This approach addresses waste management challenges while creating a new revenue stream for both partners.
Timeline And Technical Development Progress
Rainbow and Mosaic target initial production in 2030, subject to regulatory approvals and financing. The prefeasibility study is expected to conclude in the second half of 2027, following the appointment of SRK Consulting for the maiden mineral resource estimate.
Technical validation is underway, with Mosaic shipping approximately six tonnes of phosphogypsum feedstock to Rainbow’s South African pilot plant. This testwork is critical for refining the proprietary extraction process before scaling up to commercial operations.
