Can Narryer’s Organic Acid Leach Unlock Rocky Gully’s Rare Earth Potential?

Breakthrough in Organic Acid Leaching

Narryer Metals Limited (ASX – NYM) has unveiled encouraging preliminary metallurgical results from its Rocky Gully Critical Minerals Project in Western Australia. The company’s participation in a Minerals Research Institute of Western Australia (MRIWA) sponsored study, in collaboration with Curtin University and the Federal Government’s Critical Minerals Trailblazer program, has demonstrated that methanesulfonic acid (MSA), an organic acid, can effectively extract key rare earth elements (REEs) from clay-hosted deposits.

MSA achieved extraction rates of up to 78% for neodymium and praseodymium (NdPr), and over 80% for terbium (Tb) and dysprosium (Dy), which are critical components of the magnet rare earth element suite. These results are comparable to those obtained using hydrochloric acid (HCl), a conventional inorganic acid, which showed slightly higher extraction percentages but with a notable drawback.

Environmental and Processing Advantages

Unlike HCl, MSA leaching resulted in significantly lower dissolution of gangue elements such as iron, aluminum, and silicon. This reduced gangue dissolution is a key advantage, potentially simplifying downstream hydrometallurgical processing and lowering environmental impact. MSA is also biodegradable, has low toxicity, and is stable under processing conditions, making it an attractive alternative reactant for sustainable mineral extraction.

These findings suggest a promising pathway toward developing a cost-effective and environmentally sustainable flowsheet for extracting REEs, scandium, and gallium from Rocky Gully’s clay-hosted mineralisation.

Next Steps – Optimization and Bio-Leaching

Narryer plans to continue metallurgical test work to optimize acid concentrations and extraction efficiencies, including applying leaching to beneficiated concentrates. Beneficiation, which separates valuable ore from waste, has already shown potential to increase total rare earth oxides (TREO) content by up to 124% in the main mineralised horizon.

In addition, the company is collaborating with Estonian biomining specialist BiotaTec to explore bio-leaching techniques for scandium and REE extraction. Bio-leaching offers a potentially low-cost and environmentally friendly method to selectively recover metals, particularly scandium, which is enriched near surface in iron oxide-rich clays at Rocky Gully.

Strategic Location and Mineralisation Highlights

The Rocky Gully project benefits from near-surface mineralisation hosted in free-dig clays, which could reduce mining and crushing costs. It is strategically located near sealed roads, power infrastructure, and ports in Western Australia’s Great Southern region, facilitating efficient logistics.

Previous drilling at the Ivar Prospect within Rocky Gully has identified extensive scandium mineralisation over 1.6 km strike and 900 m width, with grades exceeding 100 ppm Sc2O3 and up to 518 ppm in high-grade zones. Rare earth oxide grades are also significant, with intersections reporting up to 1.8% TREO over one meter. The presence of vanadium and gallium further enhances the project’s value proposition.

Outlook

Executive Chairman Richard Bevan emphasised the importance of these early results, noting the potential for an environmentally sustainable extraction process to position Rocky Gully as a reliable source of critical minerals amid global supply chain uncertainties. The company is preparing for a maiden resource drilling program informed by these metallurgical insights.