Rainbow Rare Earths (LSE:RBW) - 'Undervalued?' Investment series, with George Bennett

Interview with George Bennett, CEO of Rainbow Rare Earths

Our previous interview: https://www.cruxinvestor.com/posts/rainbow-rare-earths-lserbw-us-govt-backed-miner-targets-2027-production-from-waste-processing-8115

Recording date: 9th September 2026

Rainbow Rare Earths (LSE:RBW) is pursuing a structurally different route into rare earth supply than most of its peers. Rather than mining hard rock, the company reclaims rare earths from phosphogypsum - the waste residue generated when phosphate rock is processed into phosphoric acid for the fertiliser industry. Because the rare earth content in phosphate rock is too low to mine economically on its own, it has historically been discarded in gypsum waste stacks; Rainbow's proprietary process recovers it from that existing above-ground resource using leaching and ion exchange, avoiding the drilling, crushing and milling costs that dominate capital spending on conventional rare earth projects.

The company is advancing two projects built on this model. Phalaborwa, in South Africa, is the more advanced of the two, currently 75% through its definitive feasibility study, with a post-tax IRR estimated at 38% using December 2024 spot pricing (rising to a CEO-cited 40-45% at more recent pricing), an EBITDA margin of 70-75%, and capital costs of circa $325-350 million. Rainbow currently owns 85% of Phalaborwa, with an option to move to 100% next year. Uberaba, in Brazil, is a joint venture with The Mosaic Company (NYSE:MOS), in which Rainbow holds 49%. A March 2026 Economic Assessment put Uberaba's post-tax NPV10 at $916 million, IRR at 45%, average annual EBITDA at $217 million over a 30-year mine life, and payback at 1.7 years; a Pre-Feasibility Study for the project formally commenced in September 2026.

Management's central argument is that the market has not yet caught up with the combined earnings power of the two projects. CEO George Bennett points to a combined attributable EBITDA estimate of circa $300 million by 2030 - roughly 75% of the EBITDA forecast for Serra Verde, a comparable Brazilian rare earths project that was recently acquired in a deal valuing it at $2.8 billion - against Rainbow's own market capitalisation of circa $250 million. Independent benchmarking cited in the interview supports the cost-position argument: Benchmark Mineral Intelligence reportedly ranks Rainbow among the lowest-cost rare earth producers in the West, while Argus Media ranks it among the highest-margin.

The investment case is also supported by third-party validation. TechMet, a critical minerals fund holding circa 12% of Rainbow, brought in the U.S. International Development Finance Corporation, which has committed $50 million of project equity to Phalaborwa, convertible at Final Investment Decision (expected around Q3 2027). Mosaic, a Fortune 500 fertiliser producer, is Rainbow's partner on Uberaba. Rainbow is also evaluating a U.S. listing, having engaged BMO Capital Markets, partly in response to the disproportionate market cap uplift Mosaic received relative to Rainbow when their joint venture was announced.

Remaining funding gaps are relatively modest against committed capacity - circa $70 million at Phalaborwa and circa $50 million at Uberaba - and near-term catalysts include binding offtake term sheets and a solvent extraction technology partner selection, both expected before the end of 2026. Investors should note both projects remain pre-FID, with first production not expected until 2029 (Phalaborwa) and 2030 (Uberaba), and that some reported capital cost figures for Uberaba have varied pending finalised feasibility numbers.

Learn more: https://www.cruxinvestor.com/companies/rainbow-rare-earths

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