Meteoric Resources has surged its Measured Resources by 246% to 128 million tonnes at its Caldeira Rare Earth Element Project in Brazil, significantly de-risking the upcoming Definitive Feasibility Study and underpinning future development plans.
- Measured Resources increase 246% to 128Mt at 2,815 ppm TREO
- Global Mineral Resource Estimate totals 1.6 billion tonnes at 2,317 ppm TREO
- Conversion of Indicated to Measured Resources improves DFS confidence
- Robust metallurgical recoveries confirmed by extensive pilot plant testing
- Environmental approvals progressing with mining permitted in buffer zones
Measured Resource Upgrade Sharpens DFS Outlook
Meteoric Resources Limited (ASX:MEI) has announced a striking 246% increase in Measured Resources at its 100%-owned Caldeira Rare Earth Element Ionic Clay Project in Brazil. The upgrade lifts the Measured category to 128 million tonnes at 2,815 ppm total rare earth oxides (TREO), substantially enhancing geological confidence ahead of the Definitive Feasibility Study (DFS).
The global Mineral Resource Estimate (MRE) now stands at 1.6 billion tonnes at 2,317 ppm TREO, containing critical magnetic rare earth oxides including 209,000 tonnes of praseodymium oxide and 594,000 tonnes of neodymium oxide. This positions Caldeira as one of the world’s largest and highest-grade ionic adsorption clay (IAC) rare earth deposits.
Infill Drilling and Geological Modelling Drive Confidence
The resource upgrade stems from an extensive infill drilling campaign focused on the southern licences; Capão do Mel, Soberbo, and Figueira; where 304 holes totaling 9,265 metres were drilled using Aircore and Hollow Stem Auger methods. The adoption of a 50m by 50m drill spacing enabled detailed three-dimensional geological models that underpin more precise mine scheduling and operational planning in the DFS.
Measured Resources in these southern deposits jumped from 11 million tonnes to 102 million tonnes, reflecting the conversion of a significant portion of Indicated Resources. Managing Director Stuart Gale emphasised that this upgrade reduces project risk and uncertainty, bolstering investment and financing prospects.
Pilot Plant Validates Metallurgical Performance
Extensive metallurgical test work conducted by the Australian Nuclear Science and Technology Organisation (ANSTO) and ongoing pilot plant operations at Caldeira have confirmed robust recoveries averaging 55% for TREO and 71% for magnetic rare earth oxides. The leaching process uses ammonium sulfate at mild pH levels, fitting the unique characteristics of IAC deposits and enabling low-cost, simple processing without complex beneficiation.
Since December 2025, the pilot plant has operated continuously, processing over 57 tonnes of ore and producing 229 kilograms of mixed rare earth carbonate (MREC), demonstrating scalability and product quality consistent with prior test campaigns.
Environmental Approvals and Mining Methodology
The Caldeira Project’s environmental licensing is progressing, with mining permitted within the buffer zones surrounding protected ecological sanctuaries. The Preliminary License was granted in December 2025, and the Installation License is expected by the end of 2026, following site inspections and approval of environmental control plans.
The mining method will be open cut, employing truck and excavator operations to extract free-digging clay material, with no drill and blast required. This approach aligns with the project’s geological setting and supports operational efficiency.
Ongoing Drilling and Next Steps
Infill drilling continues at Barra do Pacu to convert additional Indicated Resources to Measured, further strengthening the resource base feeding into the DFS. The updated resource models and metallurgical data will inform an updated statement of Mineral Reserves and refine key project parameters.
With the world’s largest inventory of Measured and Indicated resources for IAC rare earths, Caldeira maintains its Tier 1 status. However, the project’s future hinges on timely environmental approvals and the successful execution of the DFS, which will crystallize its economic potential amid volatile rare earth markets.
Bottom Line?
Meteoric’s resource upgrade sharply reduces geological risk, but the project’s value will hinge on DFS outcomes and environmental licensing progress.
Questions in the middle?
- How will the DFS incorporate the expanded Measured Resources into updated reserve estimates?
- What impact will ongoing environmental licensing approvals have on project timelines?
- How sensitive is the project’s economics to rare earth oxide price fluctuations and recovery rates?