Superior Resources appears to have tapped into the outer edges of a large, buried porphyry system at the company’s Bottletree copper prospect in Queensland. Assay results from the first of three diamond drill holes targeting an induced polarisation chargeability anomaly have returned a massive 552.5 metres intersection at 0.16 per cent copper from 132 metres depth.
The company says the drill hole intersected extensive disseminated sulphide mineralisation over broad intervals from 132m to 681m and high-grade shear-related chalcopyrite-pyrrhotite-quartz veins returning up to 2.79 per cent copper that also contained credits of gold up to 0.24 grams per tonne and silver up to 7.8 g/t.
Encouragingly, the hole finished in mineralisation suggesting the depth extents of the system remain open.
Superior says that whilst drilling has not intersected the main mineralised porphyry stock, indicators suggest that the copper mineralisation is a late-stage mineralisation sourced from a large copper-gold porphyry system located nearby and to the west of the induced polarisation anomaly.
Further industry understanding of porphyry related systems has led the company to also interpret the copper-gold-silver veining intersected shows stark similarities with late-stage poly-metallic shear veining seen in some central European porphyry deposits including the massive Assarel porphyry copper deposit in Bulgaria.
Similarities have also been noted in mineralisation zonation at Bottletree with other Australian porphyry systems. Superior says molybdenite has been identified in drill core at Bottletree and may suggest proximity to a buried porphyry system. Analogous characteristic mineral signatures are also seen at the world-class Cadia and North Parkes copper-gold deposits.
Whilst the drilling to date is yet to intersect the targeted porphyry stock, Superior says it has identified considerable copper mineralisation over 750m strike, 500m width and down to depths more than 600m vertical extent.
An increase in geological understanding of the porphyry system at Bottletree looks to be further enhanced with Superior planning on conducting down-hole geophysical surveys. It also proposes to undertake geochronological age dating on intrusions and molybdenite for age correlations with intrusions in the Macquarie Arc in New South Wales which hosts the Cadia and North Parkes copper-gold deposit.
To further assist in refining the porphyry targets a total of 1,440 soil samples were taken over a broad two kilometre by 1.8km area. Samples are at the laboratory awaiting results.
Superior says further drilling is slated where the results from the soil-sampling survey, down hole surveys and age dating will help refine targets to narrow in on the primary porphyry source.
Assay results from selected rock chip sampling have also steered the company to prioritising five target zones of strong copper and gold in soil anomalies. Superior says samples have returned values up to an impressive 11.34 per cent copper and up to 0.08 g/t gold coincident with the induced polarisation anomalies.
Superior Resources’ Managing Director, Peter Hwang said:
“We are now well placed to test a central porphyry target where there is a large oval satellite feature supported by coincident significant copper and gold in soils and significant anomalous molybdenum in historical hole SBTRC0003 that may correlate with molybdenite in hole BTD0004 some 250m to the east. Because molybdenum occurs proximal to the core of a mineralised porphyry intrusive, and there is no antimony in rock chips to indicate high levels in a zoned porphyry system, we are confident of intersecting a buried porphyry and associated mineralisation at more moderate rather than substantial depths.”
“Bottletree represents the first of several opportunities for Superior to discover and develop large copper-gold and nickel-copper-PGE deposits within the rich endowed mineralised belts secured by the Company’s Greenvale Project tenements.”
Having hit what appears to be the edges of large porphyry system, the market will be keenly anticipating more news, not only what lies beneath, but what lies ahead for Superior.
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By Matt Birney
