Western Mines Group has reported strong Phase 5 assay results from its Mulga Tank Project, revealing broad nickel sulphide intersections with promising grades of nickel, cobalt, copper, and platinum group elements that support a hybrid mineral system.
- Broad nickel sulphide mineralisation confirmed in Phase 5 drilling
- Multiple shallow higher-grade zones with up to 0.94% Ni and 0.20g/t Pt+Pd
- Strong copper and sulphur geochemical signatures indicating active magmatic sulphides
- Results to feed into updated Mulga Tank Mineral Resource Estimate
- Ongoing assay flow expected to refine exploration targeting
Phase 5 Drilling Highlights Extensive Nickel Sulphides
Western Mines Group Ltd (ASX:WMG) has delivered its first batch of Phase 5 assay results from the Mulga Tank nickel-cobalt-copper project in Western Australia's Eastern Goldfields, confirming broad zones of nickel sulphide mineralisation across four reverse circulation drill holes (MTRC079 to MTRC082). Among these, holes MTRC080 and MTRC082 stood out with robust sulphide mineralisation and multiple shallow intervals exceeding 0.40% nickel.
Hole MTRC080, in particular, returned an impressive 235 metres at 0.28% nickel, 134ppm cobalt, and 228ppm copper from 83 metres, including several higher-grade pockets such as 10 metres at 0.57% nickel and 0.20g/t combined platinum and palladium (Pt+Pd) from 84 metres, and a peak 2-metre interval hitting 0.94% nickel with 0.16g/t Pt+Pd from 192 metres. These grades underscore the presence of significant nickel sulphide mineralisation within the Mulga Tank Ultramafic Complex.
Geochemical Indicators Point to Active Sulphide Processes
The assays revealed elevated levels of copper and platinum group elements alongside sulphur, with S:Ni (sulphur to nickel) ratios above 0.5 across the holes, which are key geochemical markers of “live” magmatic sulphide mineralisation. This signature supports the interpretation that the Mulga Tank system hosts sulphides in a form potentially recoverable by mining.
Interestingly, the company noted possible nickel depletion in some sulphide zones where copper remains enriched, a phenomenon known as Cu-Ni fractionation, which may help vector towards massive sulphide deposits downstream in the system. These subtle geochemical variations provide valuable clues for ongoing exploration targeting.
Host Rock Characteristics and Mineralisation Style
Geochemical characterisation of the host ultramafic rocks showed they are predominantly high-temperature adcumulate dunites with MgO contents exceeding 46%, indicating a favourable geological environment for large-volume, low-grade disseminated nickel sulphide deposits. However, the presence of significant higher-grade sulphide intersections suggests Mulga Tank is more likely a hybrid Type 1/2 nickel sulphide system, akin to the nearby Perseverance deposit, combining disseminated and massive sulphide styles.
Resource Infill and Expansion Potential
The Phase 5 holes were designed to infill and extend the current Mineral Resource Estimate announced in April 2025, which reported over 5.3 million tonnes of contained nickel. The new results, particularly from MTRC080 and MTRC082, will contribute to an upcoming resource upgrade. Hole MTRC080 lies between previously drilled holes MTRC046 and MTRC051, while MTRC082 targets an area outside the current resource boundary, indicating potential for resource expansion.
Managing Director Dr Caedmon Marriott highlighted that these holes confirm the continuity of mineralisation and provide multiple high-grade zones near surface, aligning with exploration objectives for Phase 5. He also flagged a steady flow of assay results expected in the coming weeks, which will further refine the understanding of the Mulga Tank system.
Strategic Implications for Western Mines Group
Western Mines is advancing Mulga Tank with a dual drilling approach, using reverse circulation drilling to delineate shallow disseminated sulphides and diamond drilling to test deeper massive sulphide targets. The ongoing assay results and geological insights feed into exploration targeting and resource modelling, underpinning the company’s strategy to unlock a globally significant nickel-cobalt-copper-platinum group element deposit.
With a market capitalisation of approximately $22 million and recent capital raises boosting exploration funding, Western Mines is well positioned to continue its aggressive exploration campaign in a highly prospective greenstone belt. The Mulga Tank project remains the largest nickel sulphide deposit in Australia by contained nickel, reinforcing its strategic importance within the company’s portfolio.
Bottom Line?
Western Mines’ Phase 5 results reinforce Mulga Tank’s position as a major nickel sulphide system, with further assays set to sharpen resource estimates and exploration focus.
Questions in the middle?
- Will upcoming assay results confirm and extend the high-grade zones identified in MTRC080 and MTRC082?
- How will the possible nickel-copper fractionation observed influence targeting of massive sulphide deposits?
- What impact will the Phase 5 drilling results have on the timing and scale of the next resource upgrade?