Terrain Minerals has announced a significant discovery at its Lort River project, located 50 kilometers northwest of Esperance in Western Australia. The company's recent aircore drilling has revealed a broad rare earths mineralized system, with anomalous mineralization found in 71% of the drill holes. This discovery is particularly exciting due to the high-grade rare earths-rich zone intercepted in one hole, which returned an impressive 8 meters assaying 3349 parts per million (ppm) total rare earth oxides (TREO).
What makes this discovery even more intriguing is the presence of heavy rare earth oxides (HREO), which make up 33% of the interval. The hit included a 6-meter slice going 4230 ppm TREO, with a best run of 3 meters at a convincing 5568 ppm, accompanied by a 37% HREO component. Heavy rare earth elements such as dysprosium and terbium are highly prized in the manufacturing of permanent magnets, particularly in electric vehicle motors, wind turbines, and defense equipment.
The Lort River project's rare earths basket is shaping up as one of its biggest selling points. Neodymium and praseodymium account for almost a quarter of the project's rare earth oxide mix, placing it firmly within the range reported by Australia's better clay-hosted deposits. Additionally, the project contains pockets rich in high-value dysprosium, terbium, and yttrium, which further enhances its potential value.
Terrain is also addressing the processing question that often hangs over many clay-hosted rare earth projects. They are working on a beneficiation and acid-leach route with support from the Western Australian Government-backed Minerals Research Institute of Western Australia (MRIWA) and Curtin University. The MRIWA-backed test work using ammonium sulphate leaching has returned negligible recoveries from Lort River samples, supporting Terrain's view that the mineralization is non-ionic and mainly hosted in clay-bound minerals such as monazite, rather than simply adsorbed onto clay surfaces.
Terrain is re-splitting all the better-than-200 ppm total rare earth oxide hits from the original composite samples, with analyses from the resulting one-meter re-split samples pending. The results are expected to home in on the downhole grade profiles from the latest aircore program before planning is finalized for a follow-up reverse-circulation (RC) drilling program. This rig can drill deeper than aircore and is expected to help resolve the depth and local lateral extent of the mineralization to a level sufficient to support future resource definition.
The company's forward program includes reviewing the pending one-meter assays to rank its best zones and assessing how the high-grade and heavy rare earth areas hang together. It will also revisit another intercept in which a 3-meter surface composite returned a hefty 5725 ppm TREO. The next assays should show whether Terrain has a tidy, clay-hosted rare earths discovery story taking shape in the paddocks northwest of Esperance.
