Terrain Minerals Confirms Up to 99% Rare-Earth Recoveries at Larin’s Lane with Scandium and Gallium Upside

Rare Earths Leaching Breakthrough at Larin’s Lane

Terrain Minerals (ASX:TMX) has delivered a metallurgical milestone for its 100%-owned Larin’s Lane Prospect in Western Australia, confirming rare-earth element (REE) recoveries reaching as high as 99% through methanesulphonic acid (MSA) leaching. This bench-scale test work, conducted by Curtin University’s C3MET group under the Minerals Research Institute of Western Australia (MRIWA) M10528 project, also revealed encouraging recoveries of scandium (up to 79%) and gallium (up to 89%), pointing to valuable by-product credits that could enhance the project’s economics.

The results mark a significant advance in understanding the metallurgical amenability of Larin’s Lane’s clay-hosted rare earths, situated within the Smokebush Project approximately 350 kilometres north of Perth. The prospect features broad zones of mineralisation over a 9 km by 3 km strike, remaining open for expansion.

Methanesulphonic Acid Emerges as a Game Changer

MSA, a biodegradable and non-oxidising organic acid, outperformed other tested lixiviants such as citric and tartaric acids. Unlike hydrochloric acid (HCl), commonly used for clay-hosted REE extraction but associated with chlorine-bearing off-gases, MSA offers a potentially lower-impact and safer processing route. Its industrial maturity and off-the-shelf availability from major suppliers like BASF add further practical appeal.

Test work showed that total REE recovery from representative clay samples could reach 83% at 50°C with 3M MSA, increasing to 99% after thermal pre-treatment (calcination) at 600°C followed by leaching at 80°C. The recovery profile was notably uniform across the REE suite, with middle rare earths (Nd to Ho) achieving over 80% extraction.

Scandium and Gallium Upside Adds Value Potential

Scandium emerged as a consistent recoverable credit, with extraction efficiencies rising from around 46% under mild conditions to nearly 79% following calcination and elevated temperature leaching. Given scandium’s critical mineral status and high market value, this could provide a meaningful secondary revenue stream.

Gallium recovery, initially modest at 12–25%, improved dramatically to 89% under combined calcination and 3M MSA leaching at 80°C. Although gallium head grades are low (20–24 ppm) and recovery correlates with aluminium dissolution, the element represents promising upside pending further optimisation.

Technical Insights and Next Steps

The leaching tests confirmed that the rare earths and associated critical minerals at Larin’s Lane are not ion-exchangeable like some Chinese clay deposits but require acid dissolution. Ammonium sulphate leaching yielded negligible recovery, underscoring the importance of acid-based processes.

Higher recoveries were accompanied by increased gangue dissolution, primarily aluminium and iron, necessitating optimisation to balance reagent consumption and purity. The well-characterised composite samples provide a solid foundation for ongoing studies.

Terrain plans further metallurgical optimisation, detailed evaluation of scandium and gallium credits, and integration of these findings into upcoming Mineral Resource estimates and scoping studies. The company also intends to advance discussions with potential partners to leverage the critical mineralisation at Larin’s Lane.

Positioning within Terrain’s Broader Portfolio

Larin’s Lane complements Terrain’s flagship Smokebush Gold and Gallium Project, which recently saw a maiden Mineral Resource Estimate at the Lightning Gold Prospect. The company maintains a diversified portfolio with projects targeting gold, copper, lithium, and rare earths across Western Australia and Queensland.

Terrain’s focus on critical minerals aligns with growing demand for rare earths and associated elements in clean energy technologies. The positive metallurgical results at Larin’s Lane add technical credibility to its rare earth ambitions and could enhance the project’s attractiveness amid increasing strategic interest in Australian critical minerals.