18 December 2025 - American Uranium Limited (ASX: AMU, OTC: AMUIF) has completed a major 2025 resource expansion drilling program at its flagship Lo Herma In-Situ Recovery (ISR) Uranium Project in Wyoming’s Powder River Basin, confirming up to 3,000 metres of new uranium mineralised trends north of the proposed Mine Units 1 and 2.
The 50-hole drilling campaign, totalling approximately 16,300 metres, delivered the strongest intercept recorded at Lo Herma to date, supporting the Company’s strategy to expand and upgrade the project’s mineral resource ahead of a planned 2026 Mineral Resource Estimate (MRE) update and Scoping Study revision.
Key Highlights
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50 resource expansion drill holes completed for ~16,300 metres in 2025
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Uranium mineralisation confirmed up to 3km north of proposed Mine Units 1 and 2
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Best intercept: 4.1 metres at 0.078% eU₃O₈, including 1 metre at 0.143% eU₃O₈ (LH-25-048)
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Best total hole result: GT of 1.41 over 7.6 metres across stacked sand units
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12 new mineral claims secured, adding 96 hectares contiguous with the project area
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Drilling and hydrogeological testing further de-risk ISR development
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MRE update and additional drilling planned for 2026
Drilling Confirms Scale and Continuity
The program targeted extensions of known mineralised trends to the north of existing resources, with drilling completed across multiple lines perpendicular to interpreted roll-front uranium systems. Mineralisation was encountered across all targeted trends, demonstrating continuity of uranium-bearing sand units in both the Wasatch and Fort Union formations.
The standout result came from drill hole LH-25-048, which intersected 13.5 feet of mineralisation at an average grade of 0.078% eU₃O₈, contributing to a total hole GT of 1.41, the highest recorded at Lo Herma to date.
Drilling north of proposed Mine Unit 2 also returned encouraging results, including 12.5 feet at 0.036% eU₃O₈ in hole LH-25-050, reinforcing the prospectivity of this area, which remains open along strike.
Advancing Towards Development
In parallel with drilling, American Uranium completed hydrogeological pump testing designed to validate aquifer transmissivity - an essential step in advancing the project toward ISR mine development. Results from the hydrogeological program are expected shortly and will inform future wellfield design and development planning.
Speaking about the drill results, American Uranium’s CEO and Executive Director Mr Bruce Lane commented:
Speaking about the drill results, American Uranium’s CEO and Executive Director Mr Bruce Lane commented:
“We are delighted that this resource expansion drilling has delivered strong grades with generous thicknesses in multiple stacked sands of both the Wasatch and the Fort Union formations. We remain very optimistic that the results of this expansion drilling campaign at Lo Herma can be brought into additional resource pounds. This year’s drilling has successfully demonstrated that the host sandstone units contain reliable continuity of mineralisation across extended trends for 3km (10,000ft) to the north of the current proposed mine units. With resource expansion drilling now completed for 2025, we look forward to the full geological evaluation of these results in early 2026 ahead of the next phase of drilling. Petrotek’s hydrogeological testing report is expected shortly which, along with the latest drilling data, will help guide the next steps of project development.
“AMU continues to both grow and de-risk the Project as we progress toward an update of the Lo Herma Scoping Study in 2026.”
Strategic Land Expansion
To secure the newly identified mineralised trends, the Company has staked 12 new mineral claims covering approximately 96 hectares immediately north of proposed Mine Unit 2. These claims are contiguous with the existing project boundary and aligned with interpreted uranium roll-front trends.
Next Steps
With the 2025 program complete, American Uranium plans to resume drilling in 2026, focusing on:
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Infill drilling to improve resource confidence
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Additional monitoring well installations
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Targeted step-out drilling to further expand the resource footprint
This work will underpin an updated Mineral Resource Estimate and Scoping Study, positioning Lo Herma as a growing ISR uranium development opportunity in one of the world’s most established uranium districts.
About us:
About American Uranium
American Uranium Limited (ASX:AMU; OTCID:AMUIF) is focused on defining and developing economic in-situ recovery (ISR) uranium resources as part of the U.S. domestic uranium mining revival. AMU’s flagship and most advanced Lo Herma Project leads the Company’s project portfolio and is strategically positioned in Wyoming’s Powder River Uranium Basin, the most significant uranium production district in the U.S.
Contact details:
Jane Morgan
Investor & Media Relations Manager
M: +61 405 555 618
[email protected]
