Western Mines Group Strikes Richest Nickel Sulphide Intersection at MTRC009

Western Mines Group Mulga Tank Nickel Sulphide Discovery at MTRC009

Western Mines Group (ASX: WMG) has reported what the company describes as its richest basal nickel intersection to date at the Mulga Tank Ni-Co-Cu-PGE Project in Western Australia, with hole MTRC009 returning 116m at 0.50% Ni from 1,303m, including 38m at 0.71% Ni. According to the ASX announcement, the deeper basal zone also contained 12 separate 1m samples above 1% Ni, with a peak result of 1m at 2.34% Ni from 1,382m.

For investors, the importance of the announcement extends beyond a single intercept. In the release, Western Mines Group linked the results to a broader geological interpretation that Mulga Tank may host a Perseverance-style basal massive sulphide deposit along the base of the intrusion, while continuing to demonstrate scale through extensive disseminated nickel sulphide mineralisation.

Key Results From MTRC009

The new assays relate to the diamond core tail of hole MTRC009 (EIS9), drilled in the central part of the Mulga Tank Complex. The hole targeted a magnetic high that coincided with a conductive MobileMT anomaly in the basal zone.

The main drilling results reported in the announcement are set out below.

According to the company, cobalt, copper, sulphur, platinum and palladium were also elevated alongside the nickel mineralisation. That matters because these associated elements are commonly used to help assess whether nickel is hosted in sulphides rather than only in the surrounding ultramafic rock.

Why This Announcement Is Material

This is a high-materiality exploration update because it combines thickness, grade improvement at depth, and supportive geological observations in one hole. The ASX release states that MTRC009 returned the highest-grade basal intersection yet encountered at Mulga Tank.

That distinction is important. Broad disseminated nickel sulphide intervals can demonstrate scale, but deeper basal zones with stronger grades and signs of sulphide concentration are often where explorers look for more compact, potentially higher-value sulphide accumulations.

Western Mines Group also reported several visual and geological indicators in MTRC009 that support this line of thinking:

• Remobilised massive nickel sulphide veinlets
• Large immiscible sulphide segregations
• Coarse disseminated and interstitial sulphides
• Elevated copper and platinum-palladium values
• An overall S:Ni ratio of 1.1 across cumulative mineralised intervals

Taken together, these observations are being interpreted by the company as evidence of an active magmatic nickel sulphide system.

Managing Director Commentary

"We are increasingly convinced the Mulga Tank Ultramafic Complex could host a very significant Perseverance-style massive sulphide deposit somewhere on its basal contact," said Dr Caedmon Marriott, Managing Director.

He added that the most important feature was not only the grade, but "the style of mineralisation" including globules, remobilised sulphide segregations and veins.

What the Broader Hole Shows About Mulga Tank

In the announcement, the company said MTRC009 was drilled to 1,540.5m total depth and intersected around 900m of high-MgO dunite ultramafic from 522m to 1,437.5m, before entering footwall basalt and silicified shales.

The hole contained multiple broad mineralised intervals, not just one isolated basal intersection. That broader profile matters because it points to a large mineralised system extending through much of the ultramafic sequence.

According to the release, these intervals cumulatively total 820m at 0.30% Ni, with 135ppm Co, 67ppm Cu, 27ppb Pt+Pd and an S:Ni ratio of 1.1.

For investors, this dual profile of scale near and through the intrusion plus grade improvement in the basal zone is likely to be a key focus. It suggests that Mulga Tank is being assessed not only as a large nickel inventory, but also as a system where deeper targeting may refine more valuable sulphide zones.

What Does Basal Massive Sulphide Mean?

A central concept in this announcement is basal massive sulphide. This is a technical term, but the underlying idea is straightforward.

In a mafic or ultramafic intrusion, molten rock can carry droplets of sulphide liquid. Because sulphide liquid is dense, it may settle toward the base of the intrusion, known as the basal contact. If enough sulphide accumulates there, it can form a more concentrated body of nickel, copper, cobalt and platinum group elements than is found in broadly disseminated mineralisation.

Why Does This Matter to Investors?

• Disseminated sulphides can indicate scale, but grades are usually lower.
• Massive or semi-massive sulphides are more concentrated and can materially improve the grade profile.
• If such sulphides are found in sufficient thickness and continuity, they may have a stronger impact on project economics than broad low-grade zones.
• Geological signs that sulphides have moved, pooled or concentrated can help explorers target where denser sulphide bodies may lie nearby.

Furthermore, a few useful terms from the announcement are worth clarifying:

• Basal zone: the lower edge of the intrusion where dense sulphides may collect.
• Disseminated sulphides: small sulphide grains spread through the rock.
• Massive sulphide: a much more concentrated sulphide-rich zone.
• PGE: platinum group elements, in this case mainly platinum and palladium.
• S:Ni ratio: a geochemical measure used to assess whether nickel is associated with sulphides.
• Adcumulate dunite: a high-temperature ultramafic rock with very little trapped material between its mineral grains.

According to the company, Mulga Tank is showing the ingredients that may support this type of sulphide accumulation. However, whether drilling eventually intersects a true in-situ semi-massive or massive sulphide body remains a matter for future exploration.

Why the Host Geology Is Drawing Attention

Western Mines Group described the host rock in MTRC009 as almost entirely high-temperature adcumulate to extremely adcumulate dunite, averaging 48.6% MgO and 0.31% Al2O3 across the ultramafic section.

This geological detail is technical, but its purpose is investor relevant. In the report, MgO is used as an indicator of high-temperature ultramafic composition, while low Al2O3 is used as a proxy for limited trapped interstitial material. Together, these measures support the company's view that the system is a fertile magmatic environment for nickel sulphide mineralisation.

The release also notes that elevated sulphur, copper and platinum group elements correlate with visible sulphides in the core. According to the company, that supports the interpretation that much of the nickel is hosted in sulphide form. That distinction matters because sulphide-hosted nickel is generally the target style most closely followed by the market in magmatic nickel exploration.

How MTRC009 Fits Into the Larger Mulga Tank Project

MTRC009 is part of a broader deep drilling effort at Mulga Tank. Western Mines Group said it has now completed nine deep diamond holes across the main body of the complex.

According to the announcement, the sulphide-enriched basal zone can be traced laterally over several hundred metres to kilometres, including a cited span of 2.4km from MTRC011 to MTD027. This kind of continuity can strengthen confidence that the company is mapping a broader mineralised architecture rather than isolated localised zones.

Mulga Tank also already has a large Mineral Resource Estimate, which the company referenced from its April 2025 announcement:

The project strategy described in the ASX release appears to have two clear tracks:

1. Reverse circulation drilling to infill and extend shallow disseminated nickel sulphide mineralisation
2. Deep diamond drilling and geophysics to test deeper basal massive sulphide targets

For speculative resource investors, that combination of a large existing resource base and deeper discovery potential is often an important part of the project narrative.

Upcoming Catalysts From the ASX Release

The announcement outlined several next steps that investors are likely to monitor closely over coming months.

A DownHole ElectroMagnetic (DHEM) survey is planned for MTRC009. In simple terms, this method is designed to identify conductive bodies close to, but not necessarily intersected by, the drill hole. In nickel sulphide exploration, that can be useful because massive sulphides are often conductive.

The company is also finalising a proposed active seismic survey of about 100 line kilometres across roughly 35km². According to Western Mines Group, the aim is to better map the three-dimensional shape of the complex, including the prospective basal contact and possible feeder vent locations.

At the same time, the Phase 5 drilling program remains active. The company reported completion of holes MTRC078 to MTRC081 around MTRC046, plus MTRC082 near MTRC066, with pre-collaring under way for the remaining 11 cleared holes before RC drilling resumes.

Financial Snapshot and Investor Context

The announcement also provided an updated corporate snapshot.

At that valuation, WMG remains a small-cap explorer. For the market, that often means exploration results can have an outsized influence on sentiment, particularly when results point to a potentially larger sulphide target model.

Why WMG May Stay on Investor Watchlists

The latest announcement strengthens Western Mines Group's case that Mulga Tank is more than a large low-grade nickel system. According to the company, MTRC009 provides both the best basal intersection so far and more evidence that the geological processes associated with concentrated sulphide formation are present within the complex.

The immediate investment case is not based on a massive sulphide discovery having already been made. Instead, it rests on several factual points now established in the ASX release:

• A large existing nickel resource at Mulga Tank
• A stronger basal intercept in MTRC009 than previous holes
• Multiple 1m intervals above 1% Ni at depth
• Geological and geochemical indicators consistent with active magmatic sulphide processes
• Follow-up geophysics and drilling still to come

That leaves Mulga Tank positioned as a project where the current resource base provides scale, while deeper exploration continues to test whether a more concentrated nickel sulphide body may be present along the basal contact. For ASX investors tracking Australian nickel exploration, that is likely to remain the central question as the next catalysts are delivered.

Want to Track the Next Major ASX Nickel Discovery Before the Broader Market?

Discovery Alert's proprietary Discovery IQ model scans ASX announcements in real time, instantly identifying significant mineral discoveries like basal nickel sulphide systems and translating complex geological data into actionable investment insights — explore historic examples of major discovery returns to understand what early positioning can mean, then begin your 14-day free trial at Discovery Alert to stay ahead of the next significant find.