Previous exploration has identified copper, lead, zinc, silver and gold mineralisation at the Eastman Prospect. This oxidised copper-enriched zone of outcrop has been identified by geologists as being 25-50 metres wide and 300 metres long at the surface. A shale horizon with inter-beds of banded iron-formation (the “southern BIF”) outcrops immediately to the north.
The Eastman prospect consists largely of layered sequences of disseminated sulphides which displays some of the characteristics of VMS base metal deposits, including distinctive patterns of metal zonation, the presence of magnesian alteration and an association with exhalative horizons (BIF, chert-carbonate rocks). The mineralization remains open to the west. The morphology of the mineralisation is not well understood.
Newmont Pty Ltd drilled one diamond hole at the Eastman prospect in 1969, confirming supergene copper-zinc-lead-mineralisation intersected in previous percussion drilling. In 1971 and 1972 Kennecott exploration (Australia) Limited (Kennecott) drilled five diamond drillholes up to a depth of 165m. The drilling intersected an overturned sequence of altered volcanogenic rocks and sediments dipping steeply to the south. Disseminated copper, lead and zinc sulphides, hosted by altered volcanic rocks, were intersected in holes DDH1 and DDH3 located 240m apart. The best intersection was reported as 0.75m at 7.7% Zn, 3.1% Pb and 121g/t Ag (DDH1)4.
Between 2004 and 2006 10 RC holes totalling 1,638m and 1 diamond drill hole, totalling 335m were drilled. The RC drilling returned the best two intersections which were reported as follows:
Drill Hole ERC 56:
5m @ 5.76g/t Au, 45.7g/t Ag, 0.9% Cu, 56.7% Pb and 5.8% Zn from 125m including 2m @ 13.50g/t Au, 99.5g/t Ag, 1.7% Cu, 13.8% Pb and 9.0% Zn from 127m
Drill Hole ERC 57:
7m @ 0.58g/t Au, 35.2g/t Ag, 1.2% Cu, 2.3% Pb and 3.4% Zn from 118m including 1m @ 2.48g/t Au, 87g/t Ag, 3.2% Cu, 7.5% Pb and 10.1% Zn from 123m