Proof of concept drill tests on two separate high conductance magnetotelluric targets have been completed on Three Ways. Both holes TWD2001 and TWD2002 intersected mafic intrusive rock types (gabbro and dolerite) that did not explain the source to these very strong and laterally continuous magnetotelluric anomalies.
Drill hole TWD2001 intersected a weak foliated gabbro to the end of hole at 717.7 metres. Conductive rock types include a 7.8 metre interval of semi-massive pyrrhotite veins from 665 metres (Figure 2a) and a narrow 0.5 metre interval of pyrrhotite-chalcopyrite veining from 614.4 metres (Figure 2b). Although the veins contain pyrrhotite, a strongly conductive mineral, the intervals are considered too narrow to cause the magnetotelluric anomaly.
Drill hole TWD2002 intersected dolerite to the end of hole at 534 metres. No potentially conductive source rocks were observed.
No economically significant intervals of copper mineralisation or lead-zinc mineralisation are visible in either of the holes. Assays for base metals, gold and other trace elements are pending.
Geophysical techniques to improve follow-up drill positioning on these unresolved high conductance magnetotelluric anomalies are being assessed. Advanced three dimensional modelling and trials of deeper penetrating, moving loop electromagnetic techniques across the drilled targets are being considered.
The Three Ways program is funded by OZ Minerals (ASX: OZL) under the terms of the Greenfields Discovery Alliance. The project is trialing the use of magnetotelluric surveying to identify previously unrecognised, zinc and copper prospective sub-basins with no past drill history located some 130 kilometres along trend from the Dugald River zinc-lead-silver mine.Download this announcement >>