Legend Mining says seismic reprocessing and machine learning have boosted the exploration potential of its Rockford project within Western Australia’s rugged Fraser Range, about 250km east of Kalgoorlie.
The new geophysical datasets suggest a depth extension of the Mawson nickel-copper-cobalt deposit that already has an indicated resource of 860,000 tonnes at 1.34 per cent nickel, 0.88 per cent copper and 0.08 per cent cobalt, giving 11,500 tonnes of nickel, 7600 tonnes of copper and 700 tonnes.
The company says Velseis Processing has reprocessed the three-dimensional (3D) seismic cube at Mawson, integrating downhole and handheld petrophysical data. The cube confirmed the existence of a target area north of the deposit, which has been interpreted as the extension of the keel of the Mawson intrusion below the Mawson fault.
The keel has been independently identified by machine-learning data generated by SensOre, which Legend says outlined a fingerprint geochemical signature in the keel zone of the Mawson intrusion identical to that seen within the main deposit. Management says it is maturing a model for the Mawson intrusion that suggests it intruded from depth, carrying and depositing nickel-copper sulphides in traps.
The company says it will now assess the Mawson area using a high-power fixed loop electromagnetics (HPFLTEM) survey that successfully imaged conductors relating to nickel and copper enrichment at its Octagonal intrusive complex, about 40km to the west. The survey is planned for April next year.
Legend Mining executive chairman Mark Wilson said: “Whilst the main focus of fieldwork this year has been at Octagonal, this announcement is a reflection of the detailed work that has been progressing at Mawson and regional Rockford prospects. The drill target at Mawson is particularly exciting as the area is a confirmation of geology, geochemistry and geophysics. There is plenty to look forward to in 2024.”
The company previously released a maiden mineral resource estimate for the Mawson deposit of 1.45 million tonnes at 1.14per cent nickel, 0.74 per cent copper and 0.07 per cent cobalt, for 16,500 tonnes of nickel, 10,600 tonnes of copper and 1100 tonnes of cobalt. About 70 per cent lies within the higher-confidence indicated category.
Mawson mineralisation is near-surface at between 65m and 305m depth and remains open. The deposit is only the third published nickel resource in the Fraser Range.
IGO's Nova-Bollinger deposit is about 150km along strike to the south-east and contains 11 million tonnes at 1.52 per cent nickel, 0.615 per cent copper and 0.05 per cent cobalt. Mawson is showing similar metallurgical properties to Nova, implying that the potential underground ore is amenable to conventional flotation for saleable nickel and copper concentrates.
IGO also has its Silver Knight project, which has a mineral resource of 390,000 tonnes at 2.81 per cent nickel, 1.46 per cent copper and 0.14 per cent cobalt. That deposit is closer to Mawson, about 100km to the south-east and also along strike.
Legend says it will test the new “keel” target with diamond drilling as it aims to mature its portfolio of exploration targets within its 3000-square-kilometre Fraser Range acreage, which remains largely under-explored.
The Fraser Range has proved, for some, as rugged as it looks in terms of exploration success. But IGO has proved it possible and Legend is making a decent fist of following suit.
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By Andrew Duffy
