Western Mines Group Returns Broad Nickel Sulphide Mineralisation Across Mulga Tank Phase 5

Western Mines Group Confirms Broad Nickel Sulphide Mineralisation Across First Four Phase 5 Holes at Mulga Tank

Western Mines Group (ASX: WMG) has reported assay results from the first four holes of its Phase 5 reverse circulation drilling program at the Mulga Tank Project in Western Australia, with all holes returning broad zones of nickel sulphide mineralisation. According to the ASX release, holes MTRC079 to MTRC082 each intersected elevated nickel and sulphur alongside anomalous copper and platinum group elements, supporting the company's view that Mulga Tank hosts an active magmatic sulphide system.

The standout result came from MTRC080, which returned 235m at 0.28% Ni, 134ppm Co, 228ppm Cu and 32ppb Pt+Pd from 83m, including several shallower higher-grade intervals. The report also highlighted MTRC082, which returned 213m at 0.28% Ni, 128ppm Co, 96ppm Cu and 17ppb Pt+Pd from 87m, with multiple intervals above 0.40% Ni.

For investors, the latest drilling matters because it adds fresh support to the scale and continuity of mineralisation at Mulga Tank, where WMG has already reported a Mineral Resource Estimate of 1,968Mt at 0.27% Ni, containing more than 5.3Mt of nickel. The company stated that Phase 5 drilling is designed to infill the existing resource area and follow up previous stronger holes, while diamond drilling continues to test deeper targets for massive sulphide.

Phase 5 Results Show All Four Holes Are Mineralised

In the drilling update, WMG reported cumulative mineralised intervals across all four holes. Each hole recorded sulphur-to-nickel ratios above 0.5, which the company uses as an indicator that nickel is hosted in sulphide form rather than trapped in the surrounding rock.

Two points stand out in the report. First, all four holes returned broad mineralised intersections, which supports continuity within the part of the complex being drilled. Second, holes MTRC080 and MTRC082 recorded stronger copper and sulphur signatures, which WMG described as evidence of robust sulphide mineralisation.

Furthermore, that matters because copper, platinum and palladium are elements that tend to concentrate with sulphides. Their presence alongside nickel and sulphur can help geologists distinguish potentially recoverable nickel sulphide mineralisation from nickel locked in silicate minerals.

MTRC080 Delivered the Strongest Shallow Higher-Grade Zones

According to the drilling update, MTRC080 was the best-performing hole in this batch. Beyond the long cumulative intercept, it contained a cluster of shallower higher-grade zones within a broader mineralised envelope.

WMG stated that the upper part of MTRC080 showed a broad zone from around 140m depth with copper averaging approximately 600ppm and sulphur around 0.8% over about 55m. The company noted that a similar copper and sulphur-rich zone has also been seen at comparable depths in earlier holes MTRC046 and MTRC051.

From an investor perspective, repeated higher-grade zones across nearby holes can be important. They may point to a laterally continuous mineralised corridor rather than a single isolated intersection, although the true width of the mineralisation is not yet known.

What Did the Managing Director Say?

"MTRC080 returned multiple shallow zones over 0.40% Ni which is one of the exploration goals we're targeting in this phase," said Dr Caedmon Marriott, Managing Director.

"The hole also showed a number of intersections of higher grade Cu, up to 0.31% Cu, associated with the richer sulphide zones. The central-eastern portion of the Complex has generally returned richer Cu grades."

MTRC082 Supports Continuity Outside the Current Resource Area

The Phase 5 report also singled out MTRC082 as a strong follow-up hole around earlier hole MTRC066. WMG said the hole showed near-continuous mineralisation down much of its length, beginning from 87m.

Key intervals included:

• 3m at 0.64% Ni, 259ppm Co, 0.13% Cu and 0.10g/t Pt+Pd from 105m
• 15m at 0.42% Ni, 169ppm Co, 206ppm Cu from 152m
• 1m at 0.69% Ni, 307ppm Co, 341ppm Cu and 76ppb Pt+Pd from 280m

The company stated that the area around MTRC066 and MTRC082 sits outside the current Mulga Tank Mineral Resource Estimate. According to the announcement, this area is intended to be included in a future resource upgrade once Phase 4 and Phase 5 drilling is incorporated into modelling.

That is a relevant point for market watchers. If mineralisation defined outside the current resource shell is later incorporated into an updated estimate, it could support growth in tonnage or improve understanding of the project footprint.

Why Does the Host Rock Matter at Mulga Tank?

One of the more technical parts of the ASX release relates to the host rock intersected in all four holes. WMG reported that the ultramafic portions of these holes averaged around 46% MgO and low Al₂O₃, which the company interpreted as high-temperature adcumulate to extreme adcumulate dunite.

In simpler terms, dunite is a rock made mostly of the mineral olivine and is commonly associated with nickel-bearing magmatic systems. The "adcumulate" description means the rock formed under conditions where olivine crystals built up with very little unwanted material between them.

According to WMG, this style of rock can be favourable for large volumes of disseminated nickel sulphide mineralisation, similar in broad concept to Mt Keith-style systems. The company also noted that previous intersections above 1% Ni suggest Mulga Tank may not be limited to lower-grade bulk mineralisation and could instead be a hybrid Type 1/2 system, with potential for higher-grade sulphide zones as well.

What Should Investors Understand About Nickel Sulphide Systems?

Nickel deposits generally occur in two broad forms:

• Nickel sulphide deposits, where nickel is hosted in sulphide minerals
• Nickel laterite deposits, where nickel is formed by weathering near the surface

Mulga Tank is a nickel sulphide project. This is important because sulphide deposits can also carry associated metals such as copper, cobalt, platinum and palladium. In exploration, geologists look for these metals together because they can point to the movement and concentration of sulphide-rich melt within a magmatic system.

A few key terms from the report are worth understanding:

For non-specialists, the key takeaway is that broad disseminated zones can support scale, while more concentrated sulphide zones may offer grade. WMG's interpretation is that Mulga Tank may have elements of both.

Cu-Ni Fractionation May Help Vector Deeper Targets

The report also discussed possible copper-nickel fractionation, which refers to copper and nickel appearing offset rather than evenly distributed through the same interval. Dr Marriott said this may reflect "Ni depletion associated with otherwise very robust sulphide mineralisation".

In practical terms, this can happen when a sulphide melt moves through a magmatic system. Nickel may be removed earlier, while copper can remain mobile for longer and become enriched farther from the source. WMG said this pattern is recognised in other deposits and may help act as a vector towards a possible massive sulphide event.

However, this does not confirm the presence of a high-grade sulphide body. In exploration terms, it can nonetheless help refine targeting, which is relevant because WMG's diamond drilling program is continuing in parallel with RC drilling to test deeper basal massive sulphide targets.

Why Does This Geological Signal Matter?

According to WMG, areas showing strong copper and sulphur with offset nickel may indicate position relative to a past sulphide concentration event. In exploration targeting, that can help prioritise deeper drilling and refine the search for higher-grade zones within a broader mineralised system.

What Comes Next in the Mulga Tank Drilling Program?

WMG stated that a regular flow of Phase 5 assay results is expected over the coming weeks. The current batch covers holes MTRC079 to MTRC082, while assays remain pending for holes MTRC076 and MTRC077.

The report outlined several near-term points for investors to watch:

Holes MTRC076 and MTRC077 were drilled north of MTRC046, between that hole and earlier holes MTRC032 and MTRC038. These holes are relevant because WMG has previously highlighted stronger higher-grade zones in that part of the system.

Investment Context: Scale Remains the Central Theme

Mulga Tank is already large by Australian nickel sulphide standards on the numbers reported by the company. WMG's April 2025 Mineral Resource Estimate of 1,968Mt at 0.27% Ni contains over 5.3Mt of nickel, and the latest Phase 5 drilling is aimed at both resource infill and potential extension.

The company's current market metrics, as disclosed in the release, include:

• Market capitalisation: $22.16 million
• Share price: $0.17
• Shares on issue: 130.37 million
• Cash at 30 June 2026: $1.58 million

For investors, the central issue is not simply the size of the existing resource. It is whether ongoing drilling can continue to demonstrate continuity, add mineralisation beyond the current estimate boundary, and improve confidence in the potential for higher-grade zones within the broader system.

In addition, the first Phase 5 assay results appear to support the continuity side of that equation. All four reported holes were mineralised, with MTRC080 and MTRC082 delivering stronger sulphide signatures and multiple shallow higher-grade intervals. The next test will come from pending assays and whether they strengthen the case for resource growth and deeper targeting at Mulga Tank.

Ready to Catch the Next Major Nickel Discovery Before the Market Does?

Discovery Alert's proprietary Discovery IQ model scans ASX announcements in real time, instantly identifying significant mineral discoveries like the kind of large-scale nickel sulphide systems that have historically generated extraordinary returns — explore Discovery Alert's dedicated discoveries page to see what major finds have delivered, then begin your 14-day free trial to ensure you're positioned ahead of the broader market.