Key Highlights

  • AT4 (ASX:AT4) has commenced diamond drilling at Tennessee Mountain, with about 3,000 metres of HQ core from 17 drill pads planned.
  • Historical results include 24.9 metres at 0.65% WO3 from 7.68 metres, including 10.67 metres at 0.91% WO3.
  • Tennessee Mountain is being evaluated as a potential feedstock for the proposed ammonium paratungstate circuit at the Del Sol Refinery.
  • Historical drilling was largely shallow, leaving parts of the intrusive contact untested.

AT4 Limited (ASX:AT4) announced on 9 November 2026 that diamond drilling has started at its Tennessee Mountain tungsten project in the United States. The program is designed to test the strike and down-dip extent of the mineralisation. The company says the project is being evaluated as a potential company-controlled feedstock source within its US critical minerals strategy.

The Drilling Program

The program consists of about 3,000 metres of HQ diamond drilling from 17 drill pads. The holes are designed to investigate both the strike and down-dip extensions of the tungsten zone, which the company says have not been fully tested.

No new assay results are presented. The current program has only just commenced, so the historical intersections described are the only grade information provided.

Historical Results and Trenching

Historical drilling returned 24.9 metres at 0.65% WO3 from 7.68 metres, including 10.67 metres at 0.91% WO3, in hole GH-14. Hole GH-09 returned 18.38 metres at 0.72% WO3 from surface, including 13.17 metres at 0.91%. Hole GH-08 returned 13.11 metres at 0.71% WO3 from surface.

Historical trenching outlined a tungsten-bearing tactite zone about 107 metres along strike and around 4.5 metres thick, grading 0.61% WO3. AT4 says the historical drilling was largely confined to shallow levels, which leaves much of the prospective contact untested at depth.

The historical intercepts describe a tungsten system that has been tested mainly near surface. Each figure quoted is a historical result, and the current program will determine whether the mineralisation continues at depth and along strike. For readers following the project, the key comparison will be between the new holes and the historical intercepts, particularly the near-surface zones that feature in the highest-grade results.

Feedstock Strategy and Limits

Tennessee Mountain is being evaluated as a potential future feedstock source for the proposed ammonium paratungstate circuit at the Del Sol Refinery. The company will also consider third-party concentrate and offtake opportunities, and it will assess each potential feedstock through its Mineral Intelligence Engine framework.

The historical results were generated by previous operators, and there is no current resource estimate or metallurgical assessment of the tactite zone. Whether the material can be processed economically into feedstock remains to be tested.

Final Word

AT4 has begun testing whether Tennessee Mountain can Supply tungsten feedstock, using historical results as the starting point. The program’s outcome will depend on whether the drilling confirms grade and continuity beyond the shallow historical holes, and on the metallurgical work that follows. The next milestones are the assay results from the 3,000-metre program.

The assays from the 3,000-metre program will show whether the tungsten zone continues beyond the shallow historical holes, and the metallurgical work that follows will determine whether the material can be used as feedstock for the proposed circuit.