Mount Ridley Mines has reported a substantial inferred mineral resource for heavy rare earths and scandium at its Western Australian project, underpinning its multi-element development strategy.
- 122.54Mt inferred rare earth resource at 889ppm TREO including 44,610t HREO
- 367.98Mt inferred scandium resource at 57.3ppm Sc, among largest globally
- Heavy rare earth enrichment with 41% HREO/TREO ratio including dysprosium and terbium
- Metallurgical testwork confirms strong leach response for heavy rare earths
- Board strengthened with new chairman and CEO appointments
Significant Heavy Rare Earth and Scandium Resources Established
Mount Ridley Mines Limited (ASX:MRD) has unveiled a major milestone for its Mount Ridley Critical Minerals Project in Western Australia, defining a combined inferred rare earth mineral resource of 122.54 million tonnes at 889ppm Total Rare Earth Oxides (TREO). This includes a high-value 44,610 tonnes of heavy rare earth oxides (HREO), with a premium 41% HREO/TREO ratio that features 4,272 tonnes of dysprosium and 719 tonnes of terbium, elements critical to permanent magnet supply chains for electric vehicles and renewable energy technologies.
The project also hosts a substantial scandium inferred resource of 367.98 million tonnes at 57.3ppm scandium, placing it among the largest JORC-compliant scandium deposits globally. The coexistence of heavy rare earths, scandium, and gallium within the same regolith-hosted system enhances the project's potential for a multi-element development, supporting integrated processing approaches rather than isolated extraction routes.
Resource Footprint and Geological Setting
The mineralisation extends over a 15.8-kilometre strike and up to 3.75 kilometres in width across two principal blocks near Mt Ridley and Lake Halbert. The rare earth resource is distributed between Block 1 and Block 2, with Block 2 containing the bulk of the resource at 87.18Mt grading 947ppm TREO. Scandium mineralisation is spatially co-located within the same geological corridor, with Blocks 1A, 1B, and 2 forming the Central and Northern Scandium Zones. The mineralisation is shallow and laterally continuous, supporting the potential for bulk-tonnage open pit mining methods.
Mount Ridley’s extensive landholding of over 1,000 square kilometres remains largely underexplored, with more than 80% of the project yet to be tested for rare earth, scandium, and gallium mineralisation. The company plans systematic drilling throughout 2026 to expand and upgrade the resource base.
Metallurgical Validation Supports Development Prospects
Historical metallurgical testwork reviewed by the company confirms favourable leach responses for heavy rare earth elements across multiple prospects within the Grass Patch Complex, including Vincent, Winstons, Mia, Butch, Jody, and Fabian. Heavy rare earth elements demonstrated stronger leach recoveries than light rare earths, with some tests achieving up to 86.5% recovery, notably at the Winstons prospect within the current resource area.
Beneficiation testing also showed promising grade upgrades, with some samples doubling their TREO concentration after processing. Magnetic rare earth elements such as praseodymium, neodymium, terbium, and dysprosium showed strong recoveries averaging 77%, indicating potential for efficient extraction of critical elements. These findings bolster the technical foundation for advancing processing pathway evaluations and feasibility studies.
Resource Expansion via Large-Scale Re-assay Program
Mount Ridley has commenced a large-scale re-assay of approximately 3,300 historical drill samples targeting gaps in scandium, heavy rare earth, and gallium assay data. This program focuses on 134 diamond and aircore drillholes and aims to enhance resource confidence and classification without immediate new drilling. The results are expected to feed into updated geological models and resource estimates, supporting the company’s growth strategy for the multi-element deposit. This initiative builds on the company’s recent major re-assay program announced earlier in April.
Leadership Strengthened to Drive Project Advancement
In a strategic move to accelerate development, Mount Ridley appointed David Wall as Non-Executive Chairman and promoted Allister Caird to Managing Director and CEO. Wall brings over 20 years of equity capital markets experience, while Caird has been instrumental in repositioning the company as a critical minerals player. The board reshuffle aims to support ongoing exploration growth and downstream initiatives. These changes follow the company’s recent board and leadership appointments earlier this year.
Financial Position and Outlook
Mount Ridley ended the March quarter with a strengthened cash position of $2.5 million, bolstered by a $1.26 million capital raise through the exercise of options under a 3c underwriting agreement. Exploration expenditure for the quarter was modest at $352,000, focused primarily on the Mount Ridley Project. The company maintains a runway of over four quarters at current burn rates, providing financial flexibility to advance its resource expansion and metallurgical programs.
While no mining production or development activities occurred during the quarter, the company’s integrated resource base and metallurgical validation position Mount Ridley to progress towards feasibility and potential development of a multi-element critical minerals operation in Western Australia.
Bottom Line?
Mount Ridley’s expanded resource base and metallurgical validation underscore its potential as a significant multi-element critical minerals project, with upcoming assay results and feasibility studies set to shape its development trajectory.
Questions in the middle?
- How will the upcoming re-assay results impact resource classification and project economics?
- What processing pathways will Mount Ridley prioritise given the variable metallurgical responses?
- How might leadership changes influence the timeline for feasibility and project advancement?