Western Mines launches surveys to unlock Mulga Tank nickel-copper-PGE potential
The series of geophysical surveys are intended to de-risk targets ahead of Western Mines’ planned maiden drilling program.
Western Mines Group (ASX: WMG) has commenced a series of high-resolution geophysical surveys aimed at unlocking the potential of its flagship Mulga Tank nickel-copper-platinum group elements (PGE) project in Western Australia and de-risking initial drill programs.
Limited historical exploration results have produced strong evidence for a working sulphide mineral system at the project location and it has been considered highly-prospective for the target metals.
The company will use the results of a June gravity survey to help define and de-risk robust drill targets in preparation for a maiden drilling program later this year.
It is also planning 3D inversion modelling over the ultramafic Mulga Tank dunite intrusion, which is a key feature of the project’s acreage.
Modelling will help map the basal contact with the aim of finding vertically-plunging denser feeder zones or vents which can occur beneath ultramafic bodies and host major nickel-copper-PGE deposits.
MLEM survey
Western Mines has also designed an extensive moving loop electromagnetic (MLEM) survey covering the entire length of the Mulga Tank dunite intrusion to explore for buried electromagnetic bedrock conductors which could be associated with deposits of massive nickel-copper-PGE sulphides.
At 200m line spacing, the survey will be at twice the resolution of previous surveys, with a high-powered, low-frequency system offering a significant step up from earlier exploration work and taking advantage of advancements in the field.
The survey will offer greater potential for Western Mines to detect bedrock conductors.
Minigwal Greenstone Belt
The Mulga Tank project is comprised of two exploration licences covering 113 square kilometres of the southern end of the Minigwal Greenstone Belt, 190km east-northeast of Kalgoorlie.
The belt trends north-northwest over a strike of approximately 50km and is considered to be very underexplored due to the presence of shallow sand cover.
The project contains the entire Mulga Tank dunite, first identified by regional aeromagnetic surveys conducted by BHP (ASX: BHP) in the 1980s.
A single deep stratigraphic diamond drill hole through the centre of the magnetic feature showed it to be prospective for nickel sulphide mineralisation.
BHP’s follow-up drilling along the southern boundary of the intrusion produced a best result of 2m at 2% nickel from 67m.
Further nickel exploration in the area was limited until 2001 when Anaconda Nickel drilled three shallow holes across the centre of the intrusion, returning anomalous results of 2m at 0.72% nickel from 56m; 22m at 0.37% nickel from 54m including 2m at 1% from 58m; and 20m at 0.63% nickel from 62m including 4m at 1.44% from 64m.
Recent exploration
The most recent and substantive exploration work completed at Mulga Tank was by Impact Minerals (ASX: IPT) between 2013 and 2018.
After identifying 10 bedrock conductor targets through wide-spaced MLEM and fixed loop electromagnetic (FLEM) surveys, Impact ran an eight-hole diamond drilling program which produced “clear evidence” of a working nickel-copper-PGE magmatic sulphide system.
Drilling intersected wide zones of disseminated nickel sulphides within the dunite intrusion; narrow veins of high tenor nickel and copper sulphides at the base of the intrusion; and disseminated nickel sulphides and high tenor nickel sulphide veins associated with komatiite flow channel.