Western Mines’ two-pronged approach at Mulga Tank

Western Mines Group’s (ASX:WMG) recently announced reverse circulation (RC) drilling program at Mulga Tank is well underway with the first 8 holes already complete.

The company is currently undertaking both diamond and RC drilling programs at the Mulga Tank Project.

With this two-pronged approach, the recently announced RC drilling program aims to test the extent of shallow disseminated nickel sulphide mineralisation, while the diamond drilling program, ongoing since November 2022 continues to test deeper targets. Further drillholes will continue to be added to these programs, with ongoing targeting work, as the company systematically explores the Mulga Tank Ultramafic Complex.

The company also completed diamond drillhole MTD028 at the Mulga Tank Ni-Cu-PGE Project, on the Minigwal Greenstone Belt, in Western Australia’s Eastern Goldfields.

Hole MTD028 is located on the western side of the Mulga Tank Complex between previous holes MTD022 and MTD023 (EIS1). The hole was designed to test the continuity of mineralisation between these holes, possible association of mineralisation with magnetic highs and also further test the large W Conductor electromagnetic (EM) anomaly at depth.

MTD028 intersected a 950m thickness of high MgO meso-adcumulate dunite ultramafic containing disseminated magmatic sulphides (trace to 2%) that in a number of places coalesced into interstitial blebs (3% to 5% sulphide).

Towards the basal contact of the complex numerous intersections of high-tenor remobilised massive nickel sulphide veinlets were also observed (confirmed by spot pXRF readings up to 24.8% Ni).

Western Mines reports the hole demonstrated the presence of mineralisation between nearby holes MTD022 and MTD023 (EIS1), with disseminated sulphides occurring in four broad zones similar to MTD023 (EIS1). While visible sulphides were perhaps not as ‘rich’ as MTD023 (EIS1) this may have been masked by structural overprint in this area.

High-tenor remobilised massive nickel sulphide veinlets observed in the deeper portion of the hole continue to support the prospectivity of the basal contact of the Complex for deposits of massive nickel sulphide.

The company is methodically using a portable X-ray fluorescence (pXRF) device on site as part of its exploration and geochemical vectoring approach during the drilling program. Spot pXRF readings for hole MTD028 have been taken at 50cm intervals down the core.

Commenting on the Mulga Tank Project, WMG Managing Director Caedmon Marriott says: “MTD028 was both an infill hole between MTD022 and MTD023, to test lateral continuity of the disseminated mineralisation seen in those holes, and also aimed to further test the basal contact in this area – associated with the W Conductor EM anomaly and numerous remobilised massive nickel sulphide veinlets seen in surrounding holes MTD012, MTD013, MTD022 and MTD023.

The hole certainly met our expectations and the predictability is starting to become something of a feature of Mulga Tank, there’s almost no bad holes, with sulphide mineralisation encountered nearly everywhere we drill.

Overall, the level of disseminated sulphide mineralisation sat somewhere between the two neighbouring holes, better than MTD022 but perhaps not as rich as MTD023, mirroring the hole’s location – but visible disseminated mineralisation was somewhat affected by the structural overprint in this area”

Overall, the level of disseminated sulphide mineralisation sat somewhere between the two neighbouring holes, better than MTD022 but perhaps not as rich as MTD023, mirroring the hole’s location – but visible disseminated mineralisation was somewhat affected by the structural overprint in this area. Further high-tenor remobilised massive sulphide veinlets were seen at depth, confirming the basal contact of the intrusion is highly prospective for massive sulphides, which continues to confirm our belief this is likely a hybrid Type 1/2 mineral system more akin to Perseverance – with both disseminated and massive components.”

Hole MTD028 (planned hole MTP027) is the seventh hole of the phase two diamond program and is located on the western side of the Mulga Tank Complex between previous holes MTD022 and MTD023 (EIS1).

The hole was designed to test the continuity of mineralisation between these holes, possible association of mineralisation with magnetic highs and also further test the large W Conductor EM anomaly at depth.

Western Mines notes the drilling and visual results from hole MTD028 were largely as predicted, with the hole reaching the estimated pre-drill target depth of 1,000-1,100m. The hole demonstrated the presence of mineralisation between nearby holes MTD022 and MTD023 (EIS1), with disseminated sulphides occurring in four broad zones similar to MTD023 (EIS1).

Sulphide mineralisation was general “richer” than hole MTD022 (~600m W) but not as “rich” as hole MTD023 (EIS1). The shallow basalt-dolerite dykes/sills observed in the top section of the hole are likely later stage and related to faulting. A number of intersections of high-tenor remobilised massive nickel sulphide veinlets seen in the lower portion of the hole between 800-1,000m depth once again confirm the basal contact of the Complex is prospective for massive nickel sulphide deposits.

The company says while the large W Conductor underlying the western margin of the Complex is almost certainly a very large stratigraphic conductor, related to the sulphidic black shales seen in the footwall assemblage, it could potentially be masking other sulphide conductors.

Overall, Western Mines says it is encouraging that this infill hole was successful in demonstrating further disseminated nickel sulphide mineralisation whilst also highlighting the likelihood of the Mulga Tank Complex to host a hybrid Type 1/2 nickel sulphide mineral system – with both disseminated and massive sulphide components.

Images: Western Mines Group
Author Image
Written By Adam Orlando
Mining.com.au Editor-in-Chief Adam Orlando has more than 20 years’ experience in the media having held senior roles at various publications, including as Asia-Pacific Sector Head (Mining) at global newswire Acuris (formerly Mergermarket). Orlando has worked in newsrooms around the world including Hong Kong, Singapore, London, and Sydney.