Western Mines Extends Nickel Sulphide Zone by 400m with 46.4% Ni Semi-Massive Sulphides
Western Mines Group has successfully extended a high-grade nickel sulphide zone at its Mulga Tank project in Western Australia through diamond drilling, confirming a robust mineral system with promising parallels to the Perseverance deposit.
- Diamond tail extension to RC hole MTRC011 completed to 934.1m depth
- Intersected ~550m of high MgO adcumulate dunite with disseminated nickel sulphides
- Multiple high-grade semi-massive sulphide segregations with spot pXRF readings up to 46.4% Ni
- Extension of ‘cloud sulphide’ zone by approximately 400m from previous hole MTD028
- Further assays and geophysical surveys planned to target richer basal accumulations
Diamond Drilling Validates Exploration Thesis
Western Mines Group Ltd (ASX, WMG) has announced the completion of a diamond core tail extension to its previous reverse circulation drill hole MTRC011 at the Mulga Tank Ni-Co-Cu-PGE Project, located in Western Australia’s Eastern Goldfields. The drilling reached a depth of 934.1 metres, intersecting approximately 550 metres of high magnesium oxide (MgO) adcumulate dunite ultramafic rock containing disseminated magmatic nickel sulphides and multiple high-grade semi-massive sulphide segregations.
This result builds on earlier findings from diamond hole MTD028, located about 400 metres northeast, which intersected a significant 140-metre zone averaging 0.49% nickel. The MTRC011 diamond tail was designed to test the basal contact of the Mulga Tank Complex at a shallower depth and to extend the so-called “cloud sulphide” zone identified previously.
Robust Nickel Sulphide Mineral System Confirmed
The drilling revealed an active nickel sulphide mineral system with spot portable X-ray fluorescence (pXRF) readings reaching as high as 46.4% nickel in semi-massive sulphide globules. These high-tenor sulphide segregations were observed over a broad zone of about 46 metres thickness above the basal contact, confirming the presence of a mineralised zone similar in style to the Perseverance nickel deposit.
Additionally, a secondary broad zone of approximately 50 metres with average pXRF readings around 0.50% nickel was identified higher in the hole, suggesting multiple mineralised horizons within the ultramafic complex. The presence of disseminated sulphides and sulphide veining throughout the hole further underscores the significance of the nickel sulphide system at Mulga Tank.
Strategic Implications and Next Steps
Western Mines’ Managing Director, Dr Caedmon Marriott, highlighted that the results validate the company’s exploration thesis that Mulga Tank could host Perseverance-style high-grade nickel sulphide deposits at depth. The diamond tail extension to MTRC011 not only confirmed the mineralised basal zone but also extended it by roughly 400 metres from the previous drill hole MTD028.
The company plans to leverage detailed geological logging, laboratory assay results, and downhole electromagnetic (DHEM) surveys to vector towards richer basal accumulations, aiming to pinpoint the “centre of the cloud” of sulphide mineralisation. Further diamond tail extensions to other Phase 1 RC holes along the western margin are planned, alongside a deep diamond hole targeting a coincident 3D magnetic and conductive anomaly at the hinge zone of the complex.
Western Mines has also upgraded its onsite core processing facilities to improve efficiency and reduce costs, supporting the ongoing Phase 4 drilling program scheduled through the end of the year. Shareholders can expect assay results from MTRC011 in approximately five to six weeks, which will provide more definitive insights into the grade and extent of mineralisation.
Broader Context of Mulga Tank Project
The Mulga Tank Project is situated on the under-explored Minigwal Greenstone Belt and represents Western Mines’ flagship nickel-cobalt-copper-platinum group elements (Ni-Co-Cu-PGE) asset. The project hosts a significant nickel sulphide mineral system, with a Mineral Resource Estimate announced earlier in 2025 of nearly 2 million tonnes at 0.27% nickel, containing over 5.3 million tonnes of nickel – making it the largest nickel sulphide deposit in Australia.
These latest drilling results reinforce the prospectivity of Mulga Tank as a potential source of high-grade nickel sulphide deposits, which are critical for the growing electric vehicle and battery markets. The company’s dual drilling approach, combining reverse circulation and diamond core methods, allows for efficient resource delineation at both shallow and deeper levels.
Bottom Line?
With high-grade sulphide zones confirmed and extended, Western Mines is poised to refine its exploration focus and potentially unlock a major nickel discovery at Mulga Tank.
Questions in the middle?
- What will the forthcoming laboratory assay results reveal about the true grade and width of mineralisation?
- How will the planned DHEM surveys and geophysical data refine targeting for deeper massive sulphide accumulations?
- What are the timelines and capital requirements for advancing Mulga Tank towards resource upgrade and potential development?