Highlights

  • Underground resource development drilling has started at Happy Jack Lower at the Wiluna Gold Mine.
  • It is the first stage of a planned 80,000m underground drilling campaign.
  • The initial target is upgrading about 400koz of gold from Inferred to Indicated.
  • Wiluna's global Mineral Resource stands at 7.1Moz of gold.

Wiluna Mining Corporation Limited (ASX:WMC) has started underground resource development drilling at the Happy Jack Lower deposit within the Wiluna Gold Mine in Western Australia. The program is the first stage of a planned 80,000m underground drilling campaign.

Happy Jack Lower Drilling Program

The initial drilling targets an upgrade of about 400koz of gold from Inferred to Indicated classification, with infill drilling to a nominal 40m by 40m spacing. The goal is to increase geological confidence and support inclusion in future mine plans.

The campaign is expected to run for about three months, after which the rig will move to other underground conversion targets. Assay results will be released progressively.

Geology of Happy Jack

Happy Jack sits at a dilational bend in the HJK-Bulletin fault. The mineralised zone is up to 15m wide, with shear veins and strongly foliated rock next to the main fault, and mineralisation plunges steeply south.

Happy Jack was historically one of Wiluna's key high-grade underground production areas.

Resource Base and Conversion Target

Wiluna's underground Mineral Resource totals 38.4Mt at 4.01 g/t Au for 4.95Moz, including 3.51Moz in the Inferred category. The broader campaign aims to convert about 1.5Moz of Inferred gold to Indicated.

The global Mineral Resource is 91.7Mt at 2.41 g/t Au for 7.1Moz, as at 31 January 2026. The company noted there is no certainty that drilling will upgrade Inferred material to Indicated.

Key Takeaways

  • Wiluna has begun a major underground resource conversion campaign.
  • Happy Jack Lower is a historically high-grade production area.
  • Converting Inferred ounces could support future mine plans.
  • Assays will be released progressively over the next three months.