Western Mines Group (ASX:WMG) has intersected a cumulative 1,200m thickness of high magnesium oxide (MgO) adcumulate dunite ultramafic across 2,500m sequence in drillhole MTD023 completed at the Mulga Tank Nickel-Copper-PGE Project in Western Australia.
The company says drillhole MTD023 was designed to test the centre of the Mulga Tank Ultramafic Complex drilling the inferred deepest part, in order to capture and characterise a complete cross-section of the intrusion.
This hole was drilled to a depth of 1,401.3m and intersected about 1,200m of variably serpentinised and talc-carbonate altered high MgO adcumulate to extreme adcumulate dunite ultramafic (56.5 to 1,299m), beneath 56.5m of sand cover before encountering a footwall of predominantly basalt and minor shales at a depth of 1,299m.
The dunite intersection was divided by a basalt/dolerite unit about 44m thick that may represent a later dyke/sill, a xenolith, or a horizon between 2 major magma emplacements.
Disseminated magmatic sulphides were observed down most of the hole for about 623m, starting from around 156m depth.
These intervals possibly represent at least 2 major magmatic events.
Both sequences were seen to be mineralised with over 600m containing disseminated magmatic sulphides that in several places coalesced into interstitial blebs between former olivine crystals (3% to 5% sulphides) and even approaching net textured (about 10% sulphides).
Western Mines Group reports both adcumulate dunite units were mineralised with the lower unit showing some of the richest sulphide intersections seen to date across the project. At the base of the hole multiple intersections of remobilised massive nickel sulphide veinlets were observed and confirmed by pXRF readings.
Similar disseminated sulphide mineralisation was observed in phase one hole MTD020 and phase two hole MTD022, and recent mineralogical investigation work by the company has shown the sulphide component of those holes to be dominated by relatively coarse pentlandite blebs.
Commenting on the results of MTD023, Western Mines Group Managing Director Dr Caedmon Marriott says: “With the help of the EIS grant we were able to drill what we hope will turn out to be a transformative deep hole for the company and the project, unlocking significant new geological knowledge of the Mulga Tank Ultramafic Complex.
“The hole validates our geological model and demonstrates a significant working nickel sulphide mineral system with visible disseminated nickel sulphide mineralisation over 600m”
The hole validates our geological model and demonstrates a significant working nickel sulphide mineral system with visible disseminated nickel sulphide mineralisation over 600m. This evidence of huge volumes of mineralised ultramafic magma greatly enhances the prospectivity of the project.”
The company says this hole validates Western Mines Group’s geological model for the Mulga Tank Ultramafic Complex and shows clear evidence for a very extensive magmatic nickel sulphide mineral system, with large volumes of mineralised ultramafic magma within the Mulga Tank Complex.
It also notes the hole has ‘positive’ implications for the prospectivity of the project and confidence in ongoing exploration targeting.
Western Mines Group reports it is currently undertaking a 6-hole diamond drilling program totalling 4,000m to 5,000m to test several follow-up targets based on the results of the company’s first drilling program and ongoing exploration targeting work.
The company says the rig has now moved to the northwest and will begin drilling the planned hole MTP023 which will become MTD024 upon completion. This hole is designed to test the Panhandle off-hole conductor at the base of the Panhandle komatiite channel extending northwest from the main Mulga Tank Complex.
This conductor was identified from the DHEM survey of hole MTD016, and is modelled as a discrete moderate to ‘high’ conductance target at the inferred base of the channel that is permissive of massive or matrix sulphide mineralisation.
The targets and drillholes selected are based on a combination of geophysical modelling of recent downhole electromagnetic (DHEM) results and previous moving loop electromagnetic (MLEM) results along with geological interpretation of the complex, and geochemical vectoring work.
Western Mines Group is an Australian mineral exploration company focused on its flagship Mulga Tank Nickel-Copper-PGE Project in Western Australia.
The company also currently holds the Jasper Hill, Melita, Rock of Ages, Pavarotti, Youanmi, Broken Hill Bore, and Pinyalling projects.
Images: Western Mines Group Ltd
