Silver City Minerals Ltd (ASX:SCI) has identified multiple new potential copper-gold-cobalt targets at the Copper Blow project near Broken Hill.
A recent trial of an induced polarisation (IP) geophysical survey firstly detected known sulphide zones.
After this success, the survey was expanded to cover about 3.5 kilometres of prospective magnetic shear zone not yet tested by IP.
As well as the new targets, the survey detected the potential for a new style of mineralisation adjacent to Copper Blow.
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The trial of dipole-dipole and gradient array configurations was completed over the North Zone.
It was in this zone that a diamond drill hole returned an intersection of 41.2 metres at 1.3% copper and 0.4 g/t gold.
Copper, gold and cobalt are hosted in sulphides within a magnetite-quartz-biotite-rich shear zone extending for 4.5 kilometres along strike.
Data from this trial indicated that abundant sulphides in this zone responded well to IP, with elevated and anomalous IP chargeabilities.
Gradient array survey expanded
As a consequence, in order to locate new copper-gold-cobalt sulphide targets, Silver City expanded the gradient array survey to cover the prospective magnetic shear zone.
Silver City's tenements around Broken Hill.
This work showed that the North and South zones are anomalously chargeable, which the company interprets to be in response to abundant sulphide mineralisation outlined by drilling.
Extending from the North Zone to the northeast for 1 kilometre, are a series of discrete chargeability anomalies which are now being drill tested.
Anomalies unrelated to magnetic rocks
An unforeseen consequence of the IP survey was the occurrence of unexplained chargeability anomalies unrelated to magnetic rocks.
To the east and southeast of Copper Blow an anomaly extends over 600 metres along strike and is 200 metres wide.
Northeast of Copper Blow a chargeability anomaly appears to transect the magnetic horizon obliquely.
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Two discrete IP anomalies within this zone, both north and south of the magnetic horizon, are hosted in non-magnetic rocks.
The IP survey suggests that sulphide-bearing rocks are not restricted to the magnetic horizon which, to date, has been the focus of interest for copper, gold and cobalt exploration.
Potential for a similar, geologically-related, style of copper-gold mineralisation exists.
Future work
Silver City plans to expand the survey and undertake a soil sampling program in coming months to assess the geochemical signature of the IP anomalies to assist in drill targeting.