ASX-listed Lefroy Exploration is seeking to reveal the full extent of its newly discovered Burns gold-copper system located some 50 kilometres southeast of Kalgoorlie in WA. The rods are spinning again at Burns and will test a string of magnetic anomalies across a 2000 metre corridor highlighted by a recent aeromagnetic survey. Over 5000m of aircore drilling is set to pepper several high priority targets.
The Perth-based explorer set the market alight earlier this year with its Burns gold-copper-silver discovery when it unearthed a 38m drill hit going an impressive 7.63 grams per tonne gold and 0.56 per cent copper from 134m depth which contained a higher-grade core of 27m at grades averaging 10.1 g/t gold and 0.74 per cent copper from 141m.
According to the company, high-grade gold-copper mineralisation at Burns is hosted within a hematite-pyrite-chalcopyrite-magnetite altered diorite porphyry that intrudes a high magnesium basalt.
It is the magnetite alteration and veining that provides a distinct magnetic signature, the company says it used to locate and target additional Burns-style systems.
The copper and gold mineralisation hosted by both the diorite porphyry, basalt and massive magnetite veins is considered by the company to be a new style of mineralisation in the area.
Following on from the discovery, Lefroy refined the magnetic signature of the Burns intrusive, etching out six new magnetic anomalies over a 3km northwest trending corridor. The company reported the anomalies are akin to the magnetic response observed at the Burns deposit.
Interestingly the largest of the anomalies – “Lovejoy” – has a coincident gravity anomaly much like the gravity signature that covers Burns.
Stage one RC drilling was completed “onshore” last month with a total of 17 angled holes plumbing the depths of the six magnetic anomalies along the edge of Lake Randall. Drilling also tested the extents of mineralisation at Burns.
The strongest alteration in the prospective dioritic porphyry was intersected in holes at Lovejoy and Skinner with encouraging intercepts of 10m going 0.21 g/t gold, 0.6 per cent copper and 2.5 g/t silver from 218m. The same hole returned a further 8m hit at 0.22 g/t gold, 0.51 per cent copper and 1.75 g/t silver from 250m. The hole was abandoned at 258m due to high groundwater flows
Encouragingly, the last 2 metres of the hole ended in strong copper mineralisation hosted by altered diorite porphyry and basalt with associated gold and silver credits.
Assay results for the remaining 16 RC holes are expected in December.
Lefroy reported Stage two aircore “offshore” drilling has commenced and is expected to take at least 4 weeks to complete. The drilling is designed to test an area extending 700m from the shoreline out into Lake Randall utilising a specialised lake air-core drill rig.
According to the company, the program will test the extents of the magnetic anomalies from Lovejoy and around Burns. A total of 100 holes have been planned on a nominal 160m line spacings with vertical holes 80m apart that will be drilled to depths of about 50m.
Lovejoy has been earmarked by the company as a priority target, along with the smaller discrete Kenny’s Dream, given it has a coincident magnetic-gravity anomaly. The recent RC results, which the company suggests have just intersected the edge of the Lovejoy anomaly, point tantalisingly towards an altered and mineralised diorite porphyry beneath Lake Randall.
The LEX team are excited to be back out drilling at Burns and this time to evaluate the broader extent of the intrusion related system offshore beneath Lake Randall. This includes testing the priority Lovejoy and Kenny’s Dream magnetic anomalies. The drill campaign is the second stage of a strategy to scope out and demonstrate the scale of the geochemical footprint to the intrusion related system and its related mineralisation over a 2000m corridor and extending out into Lake Randall, the limits of which are still yet to be defined.
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