Western Mines Group Strikes Strongest Nickel Sulphide Result at Mulga Tank

Western Mines Group Drills Strongest Basal Nickel Intersection Yet at Mulga Tank

Western Mines Group (ASX: WMG) has reported its best basal zone result so far from the Mulga Tank Ni-Co-Cu-PGE Project in Western Australia, with geochemical assays from diamond core hole MTRC009 (EIS9) returning 116 metres at 0.50% nickel from 1,303 metres, including 38 metres at 0.71% nickel. The intersection is the richest basal result recorded to date at the project and adds weight to the company's view that the Mulga Tank Ultramafic Complex may host a Perseverance-style basal massive sulphide deposit.

The update matters because it combines two features investors typically watch closely in deep nickel sulphide exploration: scale and tenor. Across the full hole, when the new diamond tail assays are combined with previously released reverse circulation results, WMG reported 820 metres at 0.30% nickel, indicating an extensive mineralised system, whilst the deeper basal section delivered a cluster of higher-grade intervals that may help vector future drilling.

The Headline Result Sets a New Benchmark for Mulga Tank's Basal Zone

In the report, WMG described the basal zone as the most mineralised part of its deep holes to date. Hole MTRC009 (EIS9) appears to have advanced that pattern, with the strongest mix of thickness and grade yet encountered at the base of the intrusion.

The key intercepts reported from the basal zone were:

According to the announcement, the higher-grade basal zone included 12 one-metre samples above 1% nickel. That is important because it points to internal grade concentration within a broader mineralised package, rather than a flat, uniform interval.

The company also highlighted elevated copper and platinum plus palladium values through the same interval. In nickel sulphide exploration, these associated metals are commonly used as indicators that the nickel is tied to sulphide mineralisation rather than being locked in rock-forming minerals.

What Did the Managing Director Say?

"We are increasingly convinced the Mulga Tank Ultramafic Complex could host a very significant Perseverance-style massive sulphide deposit somewhere on its basal contact, and results like these from MTRC009 further reinforce that view," said Dr Caedmon Marriott, Managing Director.

"The hole returned the richest basal intersection to date with 116m at 0.50% Ni including 38m at 0.71% and contained 12 results with 1m samples of over 1% nickel."

For comparison, the company noted that nearby hole MTD028 had previously returned a basal zone of 140 metres at 0.49% nickel from 874 metres, including 82 metres at 0.55% nickel, making MTRC009 one of the strongest deep holes intersected so far.

Full-Hole Assays Point to a Large Nickel Sulphide System

Beyond the basal zone, the full geochemical profile from MTRC009 shows long runs of mineralisation through much of the ultramafic sequence. WMG reported cumulative nickel sulphide mineralisation of 820 metres at 0.30% nickel, 135 ppm cobalt, 67 ppm copper and 27 ppb platinum plus palladium, with a sulphur-to-nickel ratio of 1.1.

The broader intersections reported in the hole included:

• 188 metres at 0.27% nickel from 92 metres
• 133 metres at 0.26% nickel from 321 metres
• 63 metres at 0.21% nickel from 494 metres
• 224 metres at 0.28% nickel from 622 metres
• 48 metres at 0.30% nickel from 950 metres
• 12 metres at 0.37% nickel from 1,064 metres
• 116 metres at 0.50% nickel from 1,303 metres

According to the report, the hole was drilled to 1,540.5 metres and intersected about 900 metres of high magnesium dunite ultramafic before reaching the footwall sequence of basalt and silicified shales at 1,436 metres depth.

For investors, the significance lies in continuity. An isolated high-grade hit can attract attention, but repeated long intervals across multiple parts of one deep hole can improve confidence that the system is large enough to support further targeting work.

Why Copper, Sulphur and PGEs Matter in Nickel Sulphide Exploration

Nickel results can look similar on the surface; however, not all nickel mineralisation is equal from a mining perspective. The key distinction in WMG's update is between nickel in silicate minerals and nickel in sulphide minerals.

When nickel sits inside common rock minerals such as olivine, it is generally harder to extract using standard processing routes. By contrast, when nickel is hosted in sulphide minerals, it is usually considered more suitable for conventional flotation methods used at many nickel sulphide operations.

Which Indicators Support Sulphide-Hosted Nickel?

Geologists often use a group of chemical indicators to determine which type they are seeing. In the Mulga Tank update, those indicators included:

• Elevated sulphur
• Anomalous copper
• Elevated platinum and palladium
• A sulphur-to-nickel ratio above 0.5

MTRC009 returned a whole-hole S:Ni ratio of 1.1, which the company said supports the view that nickel is present in sulphide form. This matters because the exploration target is not simply bulk nickel in ultramafic rock, but a potentially more concentrated magmatic nickel sulphide system.

A further useful concept for non-specialist investors is "tenor". In simple terms, tenor refers to how metal-rich the sulphide liquid was when the deposit formed. WMG's report points to remobilised sulphide veinlets and segregations giving 1% to 2% nickel over one-metre samples even where visible sulphide content was less than 10% to 20%. According to management, that may indicate the sulphide liquid itself was relatively metal-rich.

What a Perseverance-Style Target Means

WMG continues to frame Mulga Tank against a Perseverance-style target model. In practical terms, that means a search for high-grade sulphide accumulations at the base of an ultramafic intrusion, where dense sulphide liquids can collect along the basal contact.

The report outlined several geological observations that support this model:

• Multiple deep holes have intersected an active basal zone
• A dolerite marker unit appears in several holes about 800 metres above the footwall
• Large sulphide globules, remobilised sulphide veinlets and sulphide segregations have been observed in core
• Spot portable XRF readings in sulphide veinlets were reported at up to 55.0% nickel
• The basal contact has now been intersected in multiple holes across the complex

These features do not confirm an economic massive sulphide body, but they do help build a geological case for one. Furthermore, the company's task now is to identify where any in-situ sulphide accumulation may sit along the broader basal contact.

Nine Deep Holes Are Building a Clearer Picture of the Complex

In the release, WMG stated that it has now completed nine deep diamond holes across the main body of the Mulga Tank Complex. The basal sulphide zone is reported to be traceable laterally over several hundred metres to kilometres, with the distance between MTRC011 and MTD027 around 2.4 kilometres.

That growing drill database is helping the company map the three-dimensional architecture of the intrusion. According to the report, the sulphide-rich horizons generally dip moderately to the east and plunge slightly to the north.

This matters for targeting efficiency. If repeated geological markers and mineralised zones can be followed between holes, future geophysics and deep drilling can be directed with more precision, rather than testing the system on a purely conceptual basis.

Next Steps Focus on Geophysics and Continued Drilling

The company's next work streams are aimed at narrowing the search area for any larger basal sulphide accumulation. The ASX update outlined three near-term activities:

The proposed seismic survey is one of the more important near-term catalysts. WMG said it is finalising plans for an approximately 100 line kilometre, 35 km² active seismic programme following a recently announced EIS geophysics grant.

According to the company, the survey is intended to map the basal contact, identify possible feeder vent positions and potentially detect massive sulphide accumulations greater than 4 metres thickness under the Perseverance target model.

The DHEM survey of MTRC009 also has clear exploration value. Downhole electromagnetic surveys are commonly used after drilling to look for conductive bodies that may sit beside, below or ahead of the hole. In a system where remobilised sulphides have already been intersected, such surveys can help decide where the next deep hole should be collared.

What the Mulga Tank Update Means for Investors

For investors, the latest report adds to a thesis that now has two distinct layers.

First, Mulga Tank already has scale. WMG referenced its April 2025 Mineral Resource Estimate of 1,968 million tonnes at 0.27% nickel, containing more than 5.3 million tonnes of nickel, which the company has described as Australia's largest nickel sulphide deposit.

Second, the deeper drilling is testing whether that large disseminated sulphide system also contains more concentrated basal massive sulphide zones. MTRC009 does not answer that question fully; however, it strengthens the geological argument by reporting the project's strongest basal intersection so far and by recording multiple one-metre intervals above 1% nickel.

WMG remains a small-cap explorer, with the announcement listing 113.80 million shares on issue, a share price of $0.175, a market capitalisation of $19.92 million, and cash of $2.43 million at 31 March 2026. That valuation context helps explain why deep drill results and geophysical targeting milestones may remain closely watched by the market.

In summary, the latest Mulga Tank report does not present a discovery of in-situ massive sulphide. What it does provide is a stronger data set around the basal contact, improved evidence for nickel in sulphide form, and a clearer technical basis for the next round of targeting. For a project built around the search for a Perseverance-style deposit, those are material steps forward.

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