Niobium Recoveries Reach 53% with 57% Nb2O5 Concentrate at Aileron

Strong Metallurgical Performance Validates Aileron Processing Pathway

Encounter Resources (ASX:ENR) has reported encouraging metallurgical test results from its Green deposit within the Aileron Project, delivering niobium recoveries of 51-53% at head grades between 2.2% and 2.8% Nb2O5. The company achieved concentrate grades up to 57% Nb2O5 after refining, using established multi-stage flotation and hydrometallurgical techniques common to the global niobium industry. These outcomes demonstrate a robust beneficiation process adaptable across different mineralogical composites, a critical step toward de-risking project development.

The test work focused on beneficiation and refining steps, employing crushing, grinding, desliming, and flotation circuits targeting gangue minerals such as phosphates and silicates. Refining trials successfully reduced impurities like phosphorus to industry-standard levels while upgrading concentrate grades from 40-43% to as high as 57% Nb2O5. Such results align with operational benchmarks from the world’s three major niobium producers, suggesting Encounter’s processing route is conventional yet effective.

Resource Growth and Geometallurgical Insights Inform Next Phases

This metallurgical progress complements Encounter’s recent resource expansion, where the Green deposit’s inferred niobium resource surged by 83%, contributing to a 54% uplift in the overall Aileron resource to 120 million tonnes at 0.77% Nb2O5. The company is advancing geometallurgical modelling to integrate mineralogy and grade variability into mine planning and test work, aiming to optimise recovery and concentrate quality further. This iterative approach will guide infill drilling and refine metallurgical composites, enhancing confidence in resource classification and operational parameters.

Alongside test work optimisation, such as evaluating comminution configurations, flotation reagents, and leach conditions, Encounter is expanding efforts to produce final saleable products including ferroniobium and niobium oxide. These downstream value-add opportunities could broaden product offerings beyond concentrate sales, potentially improving project economics.

Comprehensive Pre-Development Activities Underway

Supporting development, Encounter has commenced its 2026 field season with infill drilling at starter pits to upgrade resource classifications, metallurgical sampling, sterilisation drilling for infrastructure, and environmental and geotechnical studies. The company is also pursuing regional exploration targeting both weathered and primary niobium mineralisation, alongside rare earth element-rich carbonatites and copper-gold prospects.

Parallel to technical work, Encounter is engaging with niobium market participants to align product specifications with customer requirements and pricing dynamics. This market dialogue is crucial as the company moves toward finalising product pathways and securing funding and development arrangements.

The strong metallurgical results and resource growth build on Encounter’s strategic positioning in Western Australia’s West Arunta region, a frontier for critical minerals exploration. The company’s approach balances conventional processing with targeted optimisation and market integration, laying a foundation for a potentially long-life, multi-decade mining operation.

These developments follow significant resource expansions reported in April, notably the 83% growth in Green deposit niobium resource that underpin the project’s scale. The metallurgical results also complement earlier discoveries extending high-grade mineralisation over a 4km strike at Green, which informed the recent resource update and drilling plans extending high-grade niobium mineralisation.