American Uranium (AMU) has announced the completion of its 2025 resource expansion drilling programme at the Lo Herma in-situ recovery (ISR) uranium project in Wyoming’s Powder River Basin, US.

The drilling included 50 mud rotary holes totalling around 53,460ft (roughly 16,300m), aimed at extending the existing resource base and advancing the project towards ISR mine development.

Drilling concentrated on extending resources along exploration trends north of the planned mine units 1 and 2.

The results confirmed significant mineralised extensions, with drilling intercepts extending up to 3km from previously mineralised drill-holes.

AMU CEO and executive director Bruce Lane said: “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.”

The drilling programme delivered the strongest intercept recorded so far at Lo Herma, with an updated mineral resource estimate (MRE) and additional drilling scheduled for 2026.

The top mineralised intercepts returned 4.1m at 0.078% (780 parts per million, or ppm) equivalent uranium oxide, including 1m at 0.143% equivalent uranium oxide (1,430ppm) in drill-hole LH-25-048.

The highest total hole grade thickness was 1.41 across 7.6m, occurring in two stacked sand units within the same hole.

In addition to the drilling, 12 new mineral claims covering 96 hectares have been staked to expand the project north of the planned mine unit 2.

Lane added: “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.”