American Uranium’s Lo Herma Drilling Confirms Strong Wyoming Resource Upgrade

American Uranium Confirms Strong Mineralisation Continuity at Lo Herma — Resource Upgrade and Scoping Study on Track for Q3 2026

American Uranium Limited (ASX: AMU | OTC: AMUIF) has released early drilling results from its ongoing infill program at the Lo Herma In-Situ Recovery (ISR) uranium project in Wyoming's Powder River Basin. The American Uranium Lo Herma drilling results and resource upgrade in Wyoming program confirms robust continuity of uranium mineralisation within Mine Unit 1. With 18 of 55 planned holes now completed, 61% of drilled holes have intersected mineralisation above cut-off, and the results are expected to support a resource upgrade ahead of a targeted Q3 2026 Mineral Resource Estimate (MRE) update and Scoping Study.

CEO Bruce Lane commented: "These early infill drilling results provide strong confirmation of mineralisation continuity within Mine Unit 1 and demonstrate the effectiveness of our resource upgrade strategy. With a high proportion of holes returning mineralisation above cut-off and several high-grade thickness intercepts, we are building confidence in the conversion of Inferred material to Indicated ahead of our next Mineral Resource Estimate."

Drilling Results Speak for Themselves

The 55-hole program, which commenced on 5 May 2026, has a dual mandate: increase resource confidence in Mine Unit 1 through infill drilling, and expand the resource base at Mine Unit 2 through step-out drilling along interpreted redox trends to the south.

The first 18 holes, covering approximately 3,243 metres (10,640 feet) of drilling, have delivered early results that are firmly on target:

• 11 of 18 holes (61%) intercepted mineralisation at or above the 0.02% eU₃O₈ grade cut-off
• 8 of those 11 holes exceeded the target Grade Thickness (GT) of 0.2
• The standout result, hole LH-26-026, returned a 19-foot (5.8m) intercept averaging 0.056% eU₃O₈, delivering a GT of 1.06 — the strongest result in the current program
• Multiple stacked mineralised horizons were intersected, reinforcing the roll-front continuity model across Mine Unit 1

Selected Intercept Highlights

Several holes returned multiple stacked intercepts across different depth intervals, a hallmark of the roll-front uranium style hosted in the Wasatch and Fort Union Formations of the Powder River Basin.

Understanding Grade Thickness — Why It Matters for ISR Projects

Grade Thickness (GT) is the primary technical metric used to evaluate uranium mineralisation in ISR-style projects. It is calculated simply as:

GT = Grade (%) × Thickness (feet)

For ISR uranium deposits, where ore is dissolved in-situ rather than physically mined, the combined measure of how thick a mineralised interval is and how concentrated the uranium grade is within that interval determines the practical economics of extraction. Industry convention typically targets a GT of 0.2 or greater to indicate economically meaningful mineralisation for ISR operations.

Why it matters to investors: A higher GT signals not just the presence of uranium, but mineralisation that is thick and sufficiently concentrated to be commercially viable for ISR extraction. When a majority of drill holes exceed GT 0.2 — as is the case with these American Uranium Lo Herma drilling results and resource upgrade in Wyoming — it builds confidence that the mineralised system can support production planning. Furthermore, it is a key input into resource classification and, ultimately, the economic assumptions underpinning a Scoping Study.

Key Terms Glossary

Resource Base: Where Lo Herma Stands Today

The current MRE at Lo Herma, last updated on 31 March 2026, stands at 9.45 million pounds (Mlbs) of U₃O₈ across Mine Units 1, 2, and 3. The current infill program is specifically designed to convert Inferred resources within Mine Unit 1 to the higher-confidence Indicated classification.

Lo Herma MRE by Mine Unit (as at 31 March 2026)

Importantly, the current program only covers approximately one-third of the planned 55-hole campaign. With ~22 additional infill holes targeted at Mine Unit 1 and ~15 step-out holes planned to the south of Mine Unit 2, the resource base has meaningful potential to grow and improve in confidence heading into the Q3 MRE update.

AMU's Total Wyoming Resource Picture

In addition to these defined resources, AMU holds Exploration Targets across both Lo Herma and the Great Divide Basin, with a combined range of 12.34 to 15.65 million tonnes at grades between 420–700 ppm U₃O₈. These targets are conceptual in nature and not yet JORC-compliant resource estimates, but they underscore the scale of the potential resource base under AMU's tenure.

A Project With Real Geological Pedigree

Lo Herma is located in Converse County, within Wyoming's prolific Powder River Basin — one of the most historically significant ISR uranium production regions in the United States. Active and idled ISR facilities operated by major uranium producers are situated in the immediate vicinity, including facilities associated with UEC, Cameco, and Energy Fuels.

The project sits on ~13,976 acres of mining claims and mineral leases, and benefits from an extensive historical dataset acquired by AMU in March 2023. This data package carries an estimated replacement value of ~US$15 million, comprising original drill records from approximately 1,771 drill holes dating back to the 1970s and 1980s.

AMU has digitised 1,391 original drill hole logs and has since conducted systematic modern drilling campaigns in 2023, 2024, 2025, and now 2026, building on and verifying that foundational dataset.

To date, the current program represents AMU's 187th drill hole at Lo Herma under its own campaign — a significant accumulation of geological knowledge underpinning the upcoming resource and study milestones. The American Uranium Lo Herma drilling results and resource upgrade in Wyoming program builds on this substantial database to target specific areas for resource classification improvement.

Clear Catalyst Roadmap for the Remainder of 2026

The company has outlined a well-defined set of near-term milestones that investors can track closely:

1. Complete remaining ~37 drill holes from the 55-hole program, including:
   • ~22 additional infill holes at Mine Unit 1
   • ~15 step-out holes to the south of Mine Unit 2

2. Commence longer-term aquifer pump-test program at Mine Unit 1 — a critical hydrogeological step supporting ISR mine development planning
3. Updated Mineral Resource Estimate (MRE) — targeted Q3 2026, expected to reflect conversion of Inferred resources to Indicated in Mine Unit 1
4. Scoping Study — targeted Q3 2026, subject to the MRE achieving sufficient confidence to support Scoping Study-level production targets and financial assumptions consistent with JORC Code (2012) and ASX Guidance Note 31

The Investment Case: Why Lo Herma Deserves Attention

Several elements combine to make the Lo Herma story compelling for investors tracking uranium development opportunities.

Is the Resource Base Ready for a Step-Change?

Nearly 54% of the 7 million pound study-area resource at Lo Herma remains in the Inferred category. The current drilling program is specifically designed to convert a meaningful portion of that to Indicated — a step-change that would materially support the credibility and economics of the upcoming Scoping Study.

Does the Geology Support ISR Operations?

ISR is the lowest-cost, lowest-disturbance uranium extraction method. Lo Herma sits within the Powder River Basin, a jurisdiction with an established ISR production history and neighbouring operating and permitted ISR facilities. Early hydrogeological tests have already confirmed formation permeability and transmissivity consistent with operating ISR mines, as reported in January 2026.

With 61% of holes intercepting mineralisation above cut-off in the very first batch of results, and 8 holes exceeding the GT 0.2 target, the program is validating the geological model and resource conversion thesis in a tangible way. The best single intercept of 1.06 GT (hole LH-26-026) stands among the strongest results in Lo Herma's drilling history to date.

Beyond Lo Herma, AMU holds an additional 1.66 Mlbs Inferred resource in Wyoming's Great Divide Basin, plus high-potential drill-permitted projects in the Green Mountain area and brownfields conventional uranium/vanadium assets in Utah's Henry Mountains — providing exploration optionality beyond the flagship project.

Both the updated MRE and the Scoping Study are targeted within the same quarter — Q3 2026. This represents a concentrated set of catalysts in a narrow window, offering investors a clear set of value-inflection points to monitor. The American Uranium Lo Herma drilling results and resource upgrade in Wyoming timeline provides specific benchmarks for assessing project advancement.

Understanding ISR Uranium Mining: Why Location Matters

In-Situ Recovery (ISR) represents the dominant uranium extraction method in the United States, accounting for the majority of domestic production. Unlike conventional mining, ISR involves injecting a solution through drill holes to dissolve uranium from the surrounding rock, then pumping the uranium-bearing solution to the surface for processing.

Key advantages of ISR include:

• Lower capital requirements compared to conventional mining
• Minimal surface disturbance and environmental impact
• Ability to extract uranium from deposits too deep for conventional mining
• Lower operational costs once production begins

Why Does Geological Setting Matter?

ISR requires specific geological conditions to be effective — permeable sandstone formations with contained aquifer systems. The Powder River Basin has proven ideal for ISR operations, with multiple successful facilities operating in similar geological settings to Lo Herma.

Roll-front deposits form when uranium-bearing groundwater meets a chemical barrier, causing uranium to precipitate out of solution. This creates crescent-shaped zones of concentrated uranium mineralisation that are particularly suitable for ISR extraction, as the uranium is already in contact with groundwater systems.

The geological setting at Lo Herma, hosted within the Wasatch and Fort Union Formations, represents classic roll-front uranium mineralisation typical of successful ISR operations throughout Wyoming.

Market Context: Uranium's Strategic Positioning

The uranium market has experienced significant changes in recent years, driven by renewed focus on nuclear energy as a low-carbon baseload power source. Several factors support the case for uranium development projects like Lo Herma.

Global uranium production has struggled to keep pace with reactor demand, with many mines experiencing operational challenges or depletion. Furthermore, long-term uranium contracts have increased in both price and duration as utilities seek supply security.

Recent US legislation has emphasised domestic nuclear fuel supply chain development. However, it is worth noting that Lo Herma has not received specific government backing or strategic project designation. The broader policy environment nonetheless appears supportive of domestic uranium production capabilities.

ISR operations can typically respond more quickly to market signals than conventional mines, with shorter development timelines and lower capital requirements. This operational flexibility positions ISR projects favourably in a supply-constrained market.

Key Takeaway: "American Uranium has positioned itself as a focused uranium developer in one of the United States' most proven ISR uranium jurisdictions. With strong early drilling results confirming mineralisation continuity at Lo Herma, a resource upgrade pathway clearly in motion, and both an updated MRE and Scoping Study targeted for Q3 2026, AMU offers investors a well-defined set of near-term catalysts backed by a growing, multi-project Wyoming resource base."

All resource figures are sourced from the AMU ASX release dated 31 March 2026. Exploration Target ranges are conceptual in nature; it is uncertain whether further exploration will result in the estimation of a JORC-compliant Mineral Resource in defined Exploration Target areas.

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