Wiluna on home straight for expansion study after wrapping up 175km drill drive at multimillion ounce gold camp

Wiluna Mining Corporation is in the home straight in its journey to deliver a transformational study on its Wiluna gold mine in WA, after wrapping up resource development drilling.

Wiluna (ASX:WMC) will release the feasibility study on its major sulphide development expansion after wrapping up 175km of resource definition RC and diamond drilling over the past 18 months, the equivalent of running around four marathons.

Eight rigs have been running over that time aiming to increase the confidence in the Wiluna mining centre’s gold resource, increase the confidence in high priority mining areas in its one- to five-year mine planning window, and to confirm the gold producer’s reserves.

WMC has an enviable bounty of measured and indicated resource at 2.14Moz at 5.26g/t (above 2.5g/t cut-off), with an additional inferred resource at Wiluna of 2.10Moz at 4.57g/t (above 2.5g/t cut-off), making it one of Australia’s largest gold camps.

Alongside drilling to increase the confidence of inferred resources to reserve ready measured and indicated resources, the miner is also aiming to extend potential stoping areas along strike, up-dip and down-dip.

The company’s canny strategy has been to define thick high-grade intervals at shallow levels, close to previously mined zones to enable quick development options at low cost.

The most recent results from the mammoth campaign, comprising 56 holes for 13,249m of drill core, have delivered more solid widths and grades at the high-grade Happy Jack and East Lode zones, which are shaping as major ore sources in the coming expansion.

Happy Jack shows growth potential

While much of the drilling was designed to convert inferred resources at the centrally located Happy Jack deposit, drilling has also returned high grades below known inferred mineralisation.

There have been multiple high tenor intercepts within 300m of the surface and close to the existing underground mine development in the current drill drive.

The latest intercepts from Happy Jack have included:

• 37m at 4.95g/t including 3.88m at 7.58g/t (HJRD00065)
• 65m at 7.59g/t (HJRD0008)
• 04m at 5.87g/t HJRD00100
• 31m at 3.73g/t including 3.10m at 7.85g/t (HJRD00101)
• 34m at 3.55g/t including 0.34m at 20.00g/t (HJRD00108)
• 72m at 26.84g/t including 0.83m at 53.40g/t (HJRD00113), and;
• 00m at 12.37g/t (HJRD00115).

East Lode building on history of success

Wiluna’s East Lode zone in the south mine area has delivered more than 1Moz of historic gold production, developed in the 1930s and 1940s and for a short period in the early 2000s.

Despite its history as a big and high grade gold producer, the East Lode has been sparsely drilled, with WMC’s efforts focusing on infilling inferred resource areas to the indicated category.

The company says significant high-tenor mineralisation remains in situ around previously mined stopes.

Infill drilling of the hanging wall and footwall lodes presents additional stacked lodes showing potential for resource growth.

Results included:

• 00m at 5.16g/t (WUDD0073)
• 30m at 3.95g/t including 2.00m at 7.79g/t and 2.00m at 6.30g/t (WURD0173)
• 00m at 4.34g/t (WURD0176)
• 20m at 9.11g/t (WURD0184)
• 73m at 4.03g/t including 0.73m at 6.59g/t (WURD0187), and;
• 00m at 7.03g/t (WURD0188).

Three rigs remain at the Wiluna Mining Centre for mine development planning and grade control at the multi-million ounce gold camp, where WMC produced 51,552oz at all in sustaining costs of $1,794/oz in 2020-21, underpinning a 43% increase in NPAT to $20m.

Its stage 1 expansion is due to be commissioned in the December Quarter, with production ramping up to a run rate of 120,000oz a year by the end of FY22 before expanding further with the Stage 2 sulphide development.