ASX-listed explorer, Legend Mining has completed two holes from its diamond drilling program at its Mawson nickel, copper and cobalt discovery in the Fraser Range of Western Australia. The exploration intersected a largely prospective intrusive package below previous drilling levels, confirming the Mawson mineralised intrusions extend at depth as predicted.
Additionally, 65 aircore holes have been completed and the company has also wrapped up a geophysical seismic survey over the northern part of the project.
The Mawson prospect is within the company’s Rockford project that covers more than 3000 square kilometres of tenure within the celebrated Fraser Range, about 250km east of Kalgoorlie.
The region came to prominence nearly a decade ago after Sirius Resources’ Nova-Bollinger nickel, copper and platinum discovery about 120km away.
A 14.3 million tonne resource going 2.3 per cent nickel and 0.9 per cent copper has subsequently been defined at the now producing Nova-Bollinger mine operated by mining giant IGO Limited.
The aim of Legend’s seismic survey was to define the three-dimensional architecture of the Mawson intrusion, with the resulting seismic data supporting the exploration model with an apparent large intrusive source at depth. The 3D seismic reflectors clearly map the mineralised intrusion in drilled areas down to 500m below surface and the company says the data indicates it could extend below the Mawson fault to possibly 800-1000m depth.
The two completed diamond holes intersected intrusive suites and metasedimentary packages of rocks that are consistent with the geological interpretation of the seismic data.
The first drill hole intersected the lower part of the target zone with various mafic intrusive suites, including a heavily sulphide disseminated gabbronorite intrusion at 840m downhole. Further data analysis and additional drilling will aid in refinement of the initial interpretation.
The lower zone of the second wedge hole encountered a distinct structural change where a sub-vertical metasedimentary package was intersected. The hole was terminated prematurely at 993m after the drill rods became stuck in broken ground. Preliminary structural analysis and geological logging suggest a change in intrusion geometry, with the chonolith further west.
The company’s working model will be evolved with additional data from the drilling. Legend Managing Director, Mark Wilson said: “Thorough interpretation of the seismic data based on these three holes will only be possible once all follow up information (DHTEM, geochemistry from assays, petrophysics, etc.) is received and processed.”
The third hole is currently being drilled beneath the Mawson fault near the discovery zone. The work is designed to intersect a similar seismic signature to that identified at the Mawson massive nickel-copper sulphide discovery zone that is offset by the Mawson fault.
Assay results, electromagnetic surveys and petrophysical property measurements are pending from the two completed holes.
Additionally, Legend has completed 65 aircore holes for 5675m over an area to the south-west of Mawson that is the initial stage of an extensive 30,000m regional aircore program across the entire Rockford project.
The completed aircore drilling was targeting a combination of aeromagnetic and gravity features interpreted to represent ultramafic and mafic intrusives within the same structural domain as Mawson.
The domain is characterised by an elevated gravity and low magnetic response that extends south-west and north-east of Mawson and amazingly has so far only been tested with limited aircore drilling.
Excitingly, the broad-spaced drilling intersected prospective olivine-bearing ultramafics and possibly gabbronorite-norite mafic intrusions on all six traverses. Infill air core and high-power moving loop electromagnetic surveying is planned to further evaluate the potential of the region. Drill samples from the program have been submitted for full analysis, with all assay results pending.
The company says ongoing exploration will include downhole geophysical surveys on all diamond drillholes, regional air core drilling across highly ranked regional targets and further innovative geophysical surveys across highly ranked regional targets.
Legend continues to delve deep into the mineralised nickel-copper-cobalt system at its Mawson discovery. The current data alludes to a potential treasure trove buried deep beneath the surface. With the rig of truth now plumbing the depths, time will be the telling factor of the full extent of the Mawson legend.
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By Matt Birney
