Rainbow Rare Earths Ltd (LSE:RBW, OTC:RBWRF, FRA:RR1) this week highlighted strong progress on its flagship project as it advances toward a final investment decision, following the successful commissioning of a continuous pilot plant.
Chief executive George Bennett said, in a Proactive interview, that the pilot plant marked a key milestone, allowing the company to confirm final design parameters for the leach circuit after more than a year of optimisation work. He explained that the pilot results will feed directly into the definitive feasibility study, which is scheduled for completion later this year.
Here, we take a closer look at what was discussed.
Proactive: You’ve certainly hit 2026 with the ground running, switching on the pilot plant. In practical terms, what does this mean for the project?
George Bennett: Happy New Year to you, Stephen, and to all investors watching. Rainbow continues to move forward.
Running the continuous pilot confirms the design parameters of the leach circuit we’ve optimised over the past 12 to 18 months.
This provides design input for the final DFS due later this year and produces material to confirm the solvent extraction process, which was a major de-risking step announced late last year.
Proactive: What’s the single most important change investors should understand from this latest pilot work?
George Bennett: We focused on optimising the front-end leach circuit, where about 85% of capex sits. We reduced leach stages from three to two, cut leach time from 32 hours to eight hours, halved the number of belt filters and reduced power requirements.
These changes lead to major capex savings and keep overall capital in line with what we published in December 2024.
Proactive: Why is turning a waste product into rare earths such a big deal?
George Bennett: Traditional projects involve mining, crushing, milling and cracking concentrate. Rainbow starts with chemically cracked gypsum waste, meaning no mining costs and around 60% of the flow sheet is already complete at zero cost, which drives very low capital intensity and operating costs.
Proactive: What key steps should investors watch ahead of a final investment decision?
George Bennett: Pricing has improved due to export bans and strong demand. Investors will see financing announcements, DFS completion and further updates on the Brazil project as we move toward FID in the last quarter of 2026, construction in 2027 and production in 2028.