Mount Ridley Starts Phase 1 Metallurgical Program at Grass Patch Project

Phase 1 Testwork Targets Heavy Rare Earth Processing

Mount Ridley Mines (ASX:MRD) has kicked off Phase 1 metallurgical testwork at its Grass Patch Heavy Rare Earth Element Project in Western Australia, marking a pivotal step in translating its resource base into a defined processing pathway. The program, conducted by Perth-based Nagrom laboratory, focuses on the regolith-hosted heavy rare earth (HREE), scandium, and gallium mineralisation at the Winstons and Keiths Prospects.

This initiative builds on the company’s recent establishment of maiden Mineral Resource Estimates at these prospects, which followed a substantial resource announcement in April detailing a 122.54 million tonne inferred rare earth resource with significant heavy rare earth enrichment and scandium tonnage. The testwork aims to characterise and beneficiate the mineralisation ahead of hydrometallurgical processing, a critical step in unlocking the project’s commercial potential.

Technical Leadership and Testwork Objectives

Leading the program is newly appointed Technical Advisor – Processing and Metallurgy, Chris Larder, whose expertise in Western Australian rare earth and gallium processing flowsheets is expected to shape Mount Ridley’s processing strategy. The Phase 1 program is designed to establish a robust baseline characterisation of the kaolinite-dominated saprolitic mineralisation, evaluate beneficiation pathways to upgrade total rare earth oxide (TREO) grades, and optimise leaching parameters tailored to the clay mineralogy specific to the Grass Patch Complex.

Mount Ridley’s Managing Director Allister Caird emphasised the significance of this milestone, noting it as the first major metallurgical program since defining the resource base. The outcomes will underpin subsequent stages of metallurgical development and integrate with the company’s international research partnerships, reflecting a strategic push towards a comprehensive processing solution encompassing beneficiation, extraction, and separation of its multi-element mineralisation.

Building on Historical Data and Expanding Development Pathways

While historical metallurgical testwork at the Mia Prospect and preliminary baseline work at Winstons and Keiths had focused on lighter rare earth elements, this new program zeroes in on the heavier elements and associated critical minerals. Previous testwork demonstrated strong leach recoveries and beneficiation potential, with recoveries up to 86.5% and feed grade upgrades exceeding 200%, reinforcing the viability of the Grass Patch Complex as a multi-element critical minerals project.

The Phase 1 program is the first stage of a broader, multi-stage metallurgical development pathway, which will feed into Mount Ridley’s ongoing work with institutional technology partners. This approach aims to leverage both in-house expertise and external research to optimise processing flowsheets and advance the project towards commercial readiness.

Exploration Upside and Regional Positioning

Located approximately 25 kilometres north of Esperance, the Grass Patch Complex remains significantly underexplored relative to its scale and geological potential. Recent 3D gravity inversion modelling has identified multiple new high-priority rare earth and scandium targets along strike and at depth, supporting future drilling programs planned for 2026. These findings complement the metallurgical work by highlighting the potential for resource expansion beyond the current defined zones.

Alongside its flagship project, Mount Ridley also holds the Weld Range Project in Western Australia, further positioning the company as an emerging player in the critical minerals sector. The combined portfolio offers exposure to large-scale mineral systems within established mining regions, enhancing the company’s strategic options as it progresses its metallurgical and resource development initiatives.