Rainbow Rare Earths announces an EA for the Uberaba project in Brazil and that it has reached an agreement with Mosaic (NYSE: MOS), the world leading Tampa, Florida-based American producer and marketer of concentrated phosphate and potash crop nutrients, to take the project forward.
The Uberaba project is similar to Rainbow’s flagship Phalaborwa project in that it will entail the processing of phosphogypsum, a “waste” product that is the residue from phosphoric acid production and will use Rainbow’s intellectual property (IP) to economically extract both light and heavy REE. By recovering critical REE from secondary sources, these projects eliminate many of the costs and risks associated with traditional REE mining projects, and as such are situated at the bottom of the industry cost curve.
George Bennett, CEO, commented: “The results of the EA confirm that Uberaba represents a major opportunity to replicate Phalaborwa as an additional high-margin and near-term REE development project, situated in the lowest-cost quartile for the industry. We are looking forward to applying all the learnings that have been made in the development of Phalaborwa’s flowsheet, which provide the opportunity to develop Uberaba on a faster timescale. The project is based in Brazil, a favourable jurisdiction which is emerging as an important hub for rare earths in the Americas and has been identified as a strategic partner in the development of supply chain independence by the USA. We have enjoyed working alongside our partner Mosaic, who has provided important technical and operational expertise, as well as a willingness to innovate and make quick progress, and we are delighted to have signed the Joint Project Development Agreement with them to take the project forward.”
Uberaba Economic Assessment
The Uberaba project is in the Minas Gerais state of Brazil where Mosaic is currently mining phosphate rock and producing phosphoric acid for use in the fertiliser industry. The EA envisages building a processing plant on-site to process the phosphogypsum waste residue at an annual throughput of ca. 2.7 Mtpa over an initial project life of 30 years. There is excellent potential to extend this life due to the underlying long life of the phosphate feedstock at Uberaba.
The flowsheet that has been defined for the EA uses Rainbow’s background IP developed for the Phalaborwa project, further supported by collaborative test work between Rainbow and Mosaic. The phosphogypsum from the Uberaba phosphoric acid process facility is treated for REE extraction, with the aim of delivering separated neodymium and praseodymium (“NdPr”) oxide and a samarium, europium and gadolinium plus (SEG+) product that is rich in medium and heavy REE, each at +99.5% purity. The chemically processed and cleaned phosphogypsum stream is then returned to the Mosaic Uberaba process facility.
Rainbow has presented the base case economics on the basis of spot rare earth prices published by Argus on 5 March 2026 assuming 100% payability for a combined NdPr product and 70% payability for the SEG+ product. The NPV is presented at a 10% discount rate, which matches the discount rate used for Rainbow’s Phalaborwa project.
- Basket price and operating costs calculated on 100% payability basis for NdPr and SEG+ weighted in-line with the feedstock grade
- Revenue and production statistics based on steady state throughput excluding ramp up during commissioning phase
Rare earth price sensitivity
The sensitivity to rare earth prices has been calculated by reference to a 10% increase or decrease to the base case forecast. The key financial metrics of the Uberaba Project under these different scenarios are set out below:
- Basket price calculated on 100% payability basis for NdPr and SEG+ weighted in-line with the feedstock grade
- Revenue based on steady state throughput excluding ramp up during commissioning phase
Joint Project Development Agreement with Mosaic
Further to the outstanding financial results of the EA, Rainbow and Mosaic have signed a Joint Project Development Agreement to move ahead and carry out a Pre-Feasibility Study (PFS) for Uberaba.
On completion of a positive PFS and a decision to proceed with a Definitive Feasibility Study (“DFS”), Rainbow and Mosaic currently intend to establish a joint venture with Mosaic holding 51% and Rainbow 49%, subject to negotiation of final Heads of Terms.
