AMU Lifts Lo Herma Uranium Resource 16% with 72% Rise in Indicated Confidence

Lo Herma Resource Expansion Strengthens Development Outlook

American Uranium Ltd (ASX:AMU) has delivered a substantial upgrade to its flagship Lo Herma uranium project in Wyoming’s Powder River Basin, boosting the total Mineral Resource Estimate (MRE) by 16% to 9.96 million pounds of U3O8. More notably, the Indicated Resources, the higher-confidence portion crucial for development planning, have soared 72% to 4.79 million pounds, lifting the confidence level within the proposed Scoping Study footprint from 32% to 54%. This enhanced resource base sets a firmer foundation for the Scoping Study targeted for early Q4 2026.

The updated MRE incorporates results from a comprehensive 120-hole drilling campaign completed over 2025 and 2026, which focused on expanding and upgrading resource confidence particularly within three priority Mine Units (MU1, MU2, MU3). Combined, these units now contain 7.38 million pounds of uranium, a 23% increase from prior estimates, with over half classified as Indicated. This marks a significant step forward from the 8.57 million pounds total resource reported in December 2024, reflecting both resource growth and improved delineation of mineralised trends.

In-Situ Recovery Focus and Hydrogeological Validation

The Lo Herma project is being developed with In-Situ Recovery (ISR) mining methods in mind, a technique well-established in the Powder River Basin. Hydrogeological testing within the key Mine Units has confirmed aquifer characteristics consistent with other operating ISR facilities nearby, supporting the viability of this approach. While some shallower mineralisation may be unsuitable for ISR and could require alternative mining methods, the recent drilling has prioritized deeper zones where ISR is feasible.

The Scoping Study will integrate the updated resource data with ongoing hydrogeological pump testing and metallurgical evaluations to refine development scenarios, including potential standalone ISR operations or satellite wellfield arrangements linked to regional processing infrastructure. These conceptual frameworks remain preliminary but provide a roadmap for advancing Lo Herma’s technical and permitting progress.

Exploration Target Range and Regional Context

Alongside the MRE, AMU has revised its Exploration Target Range (ETR) for Lo Herma, expanding it to between 5.88 and 7.90 million tonnes grading 500 to 700 ppm U3O8. This reflects the conversion of some previous exploration targets into the updated resource base and the addition of new mineral rights and claims. The ETR remains conceptual, with uncertainty over whether further drilling will convert these zones into JORC-compliant resources.

Lo Herma sits amid a cluster of established ISR uranium projects within Wyoming’s Powder River Basin, including operations by Uranium Energy Corp, Cameco, and Energy Fuels. The region’s long production history and existing infrastructure underscore the strategic value of AMU’s growing resource position. The company’s total Wyoming resources now stand at 11.62 million pounds U3O8 when including its Great Divide Basin assets.

Technical Rigor and Next Steps

The updated MRE follows rigorous application of industry-standard methodologies, including calibrated downhole gamma logging and Grade Thickness contour modelling, consistent with JORC Code (2012) guidelines. The resource classification reflects drill spacing, geological continuity, and confidence in mineralisation geometry. Metallurgical testing, though preliminary due to limited core recovery, indicates alkaline leach amenability comparable to other southern Powder River Basin deposits.

Looking ahead, AMU plans to incorporate hydrogeological pump test results alongside the MRE into the upcoming Scoping Study, which will evaluate mine planning, ISR wellfield design, processing options, and permitting pathways. This study will be a critical milestone in advancing Lo Herma from resource delineation toward development readiness.