Core Energy Confirms High-Grade Rare Earth Recoveries at Tunas, Advancing to Diamond Drilling

Leach Testwork Validates Recoverable Rare Earths at Tunas

Core Energy Minerals (ASX:CR3) has delivered encouraging metallurgical results from its Tunas Rare Earth Element (REE) Project in Paraná, Brazil. Leach testwork on auger samples confirmed the presence of high-grade Ionic Absorption Clay (IAC) mineralisation, with average Total Rare Earth Oxide (TREO) recoveries of 38% and Magnetic Rare Earth Oxide (MREO) recoveries of 63% in deeper samples. Notably, maximum recoveries reached 64% TREO and an anomalous 104% MREO, the latter attributed to analytical variability rather than physical over-recovery.

The leach tests employed ammonium sulphate under mild conditions, ambient temperature and low acidity, indicating that a meaningful portion of the rare earths at Tunas are amenable to simple, low-impact extraction methods. Multiple samples returned MREO recoveries above 50%, including values as high as 76%, reinforcing the strong leachability of the magnetic rare earth component within the weathered profile.

Depth Potential Opens with Diamond Drilling Plans

Auger drilling to date has been limited to about 15 metres depth due to equipment constraints, leaving many holes ending in mineralisation. Leach recoveries and recovered grades generally increased with depth, suggesting stronger mineralisation below current drilling limits. Core Energy’s Managing Director Tony Greenaway highlighted that the next exploration phase will deploy man-portable diamond drilling rigs to test the full thickness of the weathered clay profile and basement contact, allowing for more definitive metallurgical sampling.

This step is critical as the company advances toward a maiden JORC mineral resource estimate. The diamond drilling will also help overcome the current uncertainty around true mineralisation widths, as vertical auger holes only provide downhole lengths.

Size-Fraction Testing Fails to Upgrade Grades

In parallel, Core Energy conducted size-fraction test work to assess whether screening finer fractions could enhance rare earth grades. The results showed no consistent enrichment pattern, likely due to the fine silty-clayey nature of the Tunas material where finer fractions dominate. Consequently, the company will maintain bulk sample assays as the representative method for ongoing evaluation.

Strategic Value from Magnetic Rare Earths and Yttrium

The presence of recoverable magnetic rare earth oxides and yttrium adds strategic value to the Tunas Project. Yttrium, reported separately due to its economic importance, was found in significant quantities, complementing the overall rare earth profile. This aligns with the company’s earlier reports of thick, laterally continuous mineralisation with elevated grades and yttrium enrichment, supporting the project's robust exploration potential consistent rare earth grades.

Core Energy holds 100% ownership of the Tunas tenements, located about 75 kilometres north of Curitiba, Brazil. The project sits within a granitic to granodioritic orthogneiss complex, with weathered regolith profiles hosting the IAC-style REE mineralisation. This geological setting is consistent with the company's broader rare earth exploration strategy across Brazil and Australia.