Viridis Mining's Demonstration Plant for Mixed Rare Earth Carbonate production has outperformed Pre-Feasibility Study assumptions, achieving average magnetic rare earth oxide recoveries near 79% during steady operation in July 2026.
- MREO recovery averaged 78.7%, exceeding PFS assumptions
- Continuous 24-hour automated plant operation validates process design
- Feed sourced from Northern Concessions supports DFS modelling
- Ongoing optimisation expected to further improve recoveries
- Product qualification progressing with strategic partner Solvay
Demonstration Plant Outperforms Pre-Feasibility Study Benchmarks
Viridis Mining and Minerals Limited (ASX:VMM) has reported that its state-of-the-art Demonstration Plant for Mixed Rare Earth Carbonate (MREC) production at the Colossus Project has consistently exceeded the metallurgical recovery assumptions set out in its 2025 Pre-Feasibility Study (PFS). Over a stabilised five-day period in July 2026, the plant achieved an average magnetic rare earth oxide (MREO) recovery of 78.7%, peaking at 80.9%, compared to the PFS assumption of 76%. Total rare earth oxide (TREO) recovery also matched or exceeded PFS levels, averaging 64% versus 57% previously forecast.
Continuous Automated Operation Validates Commercial Flowsheet
The Demonstration Plant operates on a continuous 24-hour basis under fully automated control systems, including programmable logic controllers and integrated water and reagent recycling circuits. This scale and automation level are among the largest known outside China for this type of rare earth processing. The plant processes approximately 100 kilograms per hour of clay feed sourced from the Northern Concessions, which underpin the early mine plan for Colossus. Continuous operation has allowed Viridis to validate key process parameters, capital and operating cost assumptions, and equipment designs ahead of the Definitive Feasibility Study (DFS).
Feed Quality and Recovery Data Support DFS and Financial Modelling
The feed material for the Demonstration Plant was collected as a bulk metallurgical sample from a single location within the Northern Concessions, selected with reference to detailed geological and assay data from nearby auger drilling. The ore grades during the stabilised period averaged 3,061 ppm TREO and 957 ppm MREO, consistent with PFS life-of-mine assumptions. Metallurgical recoveries were calculated by comparing feed and residue grades, with independent laboratory assays and peer review confirming data integrity. These results provide critical input for the DFS and underpin improvements in project economics.
Process Optimisations Enhance Product Quality and Operational Efficiency
Viridis has implemented several process enhancements since initial plant start-up, focusing on MREC precipitation, filtration, and residue management. Refinements in precipitation kinetics and pH control have improved particle size and filterability, producing competent filter cakes with consistent moisture content. Optimised counter current decantation (CCD) thickener operation has improved solids underflow and overflow clarity, reducing impurities in the final product. Water treatment systems have demonstrated zero liquid discharge operation and reagent recovery, supporting sustainability goals.
Strategic Partnerships and Commercial Validation Progress
Product qualification is advancing with strategic offtake partner Solvay, with high-grade MREC samples shipped to Solvay’s La Rochelle facility in France. The Demonstration Plant also serves as a critical de-risking asset for financing and commercial negotiations, providing lenders and partners tangible evidence of the process’s robustness and repeatability. The Rare Earth Research and Processing Centre continues to host technical due diligence and government delegations, including a recent visit from European Union Commissioner Jozef Síkela, highlighting the project's strategic importance.
Next Steps Focus on Further Optimisation and DFS Finalisation
With strong confidence in current recovery levels, Viridis plans to continue process optimisation, including reagent consumption reduction and sensitivity testing of key operating variables. Vendor and EPCM teams will gain access to the Demonstration Plant to support equipment design optimisation and performance guarantees. Additional MREC samples will be produced to support ongoing product qualification with Solvay. These activities aim to solidify the DFS and underpin the Final Investment Decision targeted in the coming months.
Bottom Line?
Viridis’s Demonstration Plant performance not only validates its PFS assumptions but also sets the stage for improved project economics and smoother financing ahead of the DFS.
Questions in the middle?
- How will ongoing process optimisations impact final recovery rates and project costs?
- What are the implications of sourcing feed from a single bulk sample location for broader deposit variability?
- How will product qualification progress with Solvay influence offtake agreements and financing?