American Uranium Advances Lo Herma with Large-Scale Aquifer Testing

Hydrogeological Testing Marks Key Development Step

American Uranium Limited (ASX:AMU) has initiated large-scale aquifer pump testing at its flagship Lo Herma ISR uranium project in Wyoming’s Powder River Basin. This milestone at Mine Unit 1 represents a crucial phase in transitioning the project from resource definition to evaluation and potential in-situ recovery (ISR) development.

The testing program is designed to gather detailed hydrogeological data, including groundwater flow dynamics, hydraulic connectivity, and parameters critical for future wellfield design. These insights are essential for refining groundwater modelling and advancing permitting efforts ahead of the company’s targeted Q4 2026 Scoping Study.

Building on a Strong Resource Base and Prior Testing

This initiative follows American Uranium’s August 2026 resource update that increased Lo Herma’s total mineral resource to 9.96 million pounds of U3O8, with 7.38 million pounds situated within the proposed Scoping Study area. Notably, 54% of this contained uranium is classified as Indicated, reflecting enhanced confidence in the deposit.

The current pump testing expands upon favourable hydrogeological assessments from 2025 conducted by Petrotek Corporation, which identified sustained flow rates and minimal aquifer drawdown consistent with other permitted ISR projects in the region. The new program aims to verify these characteristics across a broader section of Mine Unit 1, providing additional data critical for the next phase of project development.

Technical Setup and Testing Configuration

The testing centers on the existing LH MW-003 pumping well within the Middle C Sand formation, supported by multiple observation wells positioned to monitor the target aquifer and adjacent geological units. Four observation wells spaced 400-500 feet from the pumping well will assess directional transmissivity, while additional wells in overlying and underlying sand units will evaluate hydraulic responses across strata.

Petrotek’s detailed test layout reflects a comprehensive approach to characterising the hydrogeological environment, which will underpin wellfield design and support regulatory submissions. The configuration is a direct follow-up to recommendations from the 2025 studies, indicating a methodical progression in technical evaluation.

Strategic Importance for Project Advancement

American Uranium’s CEO Bruce Lane highlighted the significance of this phase, noting that “pump testing is another important milestone as we progress toward our targeted Q4 2026 Scoping Study.” He emphasised that Mine Unit 1, the focus of this testing, is expected to form the initial development stage assessed in the upcoming study.

The integration of updated resource data and extensive hydrogeological testing strengthens the technical foundation for Lo Herma’s evaluation and eventual permitting. While the announcement does not specify timelines beyond the Scoping Study, the data collected will be pivotal in shaping project design and regulatory strategy.