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Writer's pictureDoug Bright

Western Mines flies geophysics in hunt for nickel sulphides

Updated: Apr 30


Western Mines Group’s deep diamond core with massive sulphide. Credit: File


Western Mines Group is homing in on what it believes is a significant nickel system after completing its latest “MobileMT” (magneto-tellurics) airborne geophysical survey to evaluate its flagship Mulga Tank nickel-copper-PGE project.


Management says the survey data gleaned from the survey has been sent to Canada for processing and preliminary results are anticipated in the next few weeks, with the final 3D dataset expected in about a month.


MobileMT is the latest innovation in airborne electromagnetic technology that uses the Earth’s naturally-occurring electromagnetic fields to map geoelectrical 3D information at high resolution, down to about 1km depth.


Western Mines engaged Expert Geophysics to undertake the survey on a 200m line spacing across its entire Mulga Tank ultramafic complex. It believes the method will effectively evaluate the whole area and assist with determining the 3D architecture of the complex and particularly the detection of massive nickel sulphide targets at, or at least near, the basal contact of the ultramafic zone – a key target in its geological model that is already being tested by deep drilling.


Mulga Tank is a major ultramafic complex in the underexplored Minigwal greenstone belt in Western Australia’s Eastern Goldfields, where historical exploration results show significant evidence for an extensive nickel sulphide mineral system that the company considers to be highly-prospective for nickel-copper-PGE mineralisation.


The survey is part of our systematic exploration strategy to unlock further knowledge of the Mulga Tank Complex. This cutting-edge technology is capable of deep 3D geoelectrical mapping of resistivity and conductivity down to >1km and we hope may be well suited to directly detecting deep massive sulphide targets at the project. We look forward to receiving the results over the next few weeks, to feed into and refine, our ongoing drilling program at the project. Western Mines Group managing director Caedmon Marriott

The company may be a junior explorer, but it wants to score a big prize in a new underexplored, but highly prospective area by the application of new concepts and technologies. The company says it is committed to using every tool in the box, including its existing 3D datasets that include magnetics, gravity, extensive geological information gained from its recent deep drillholes and the deep resistivity and conductivity mapping provided by the MobileMT system.


What differentiates Western Mines from other nickel exploration plays is the major komatiite-hosted nickel system within its portfolio. While komatiite-hosted nickel deposits are well-known in WA, generally most other major deposits are mafic intrusion-related, such as Nova Bollinger in the Fraser Range and in other famous nickel camps around the world such as Norilsk or Jinchuan.


World-class examples of komatiite-hosted nickel deposits include Kambalda (35 million tonnes at 3.1 per cent nickel), Perseverance (50 million tonnes at 2.3 per cent nickel), and Mt Keith (643.7 million tonnes at 0.58 per cent nickel).


Management believes the underexplored Minigwal greenstone belt could well contain the ultimate prize because its Mulga Tank complex contains many similarities with nearby world-class examples of komatiite-hosted nickel deposits, such as Perseverance and Mt Keith.


The Minigwal belt and its ultramafic dunite rocks were first identified by BHP in 1980s and until only recently, have remained underexplored and only tested to shallow depths due to heavy sand cover.


Previous work has unveiled significant evidence for a sulphide mineral system considered highly-prospective for nickel-copper-PGE mineralisation and Western Mines has already demonstrated through its greenfields exploration that komatiite rocks in the area are mineralised.


The company is currently undertaking a diamond drilling program at the project, with targets and drillhole selection based on a combination of geophysical modelling of recent downhole electromagnetic (DHEM) results and previous moving loop electromagnetic (MLEM) results, in addition to geological interpretation of the complex and vectoring work.


Following its recent capital raise and encouraging exploration results, management has expanded the program, with continuous drilling anticipated throughout the rest of this year and more drill holes expected to be added as required.


The program includes two deep holes that have already been drilled with the aid of the company’s $220,000 Exploration Incentive Scheme (EIS) funding.


The second EIS drillhole was completed recently to a total depth of 1548.3m, the deepest hole ever drilled at the Mulga Tank project.


The company says that the disseminated sulphides are almost all pentlandite nickel sulphides, highlighting the potential for “Mt Keith-style” mineralisation and positive implications for the prospectivity of the project and ongoing exploration.


Western Mines is keeping a close eye on the main prize and will spend much of this year drilling to see just how similar Mulga Tank is to Mt Keith.


Is your ASX-listed company doing something interesting? Contact: office@bullsnbears.com.au

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