Encounter Resources (ASX: ENR) has intersected high-grade copper mineralisation in the first drilling at the Sandover project, located 170km north of Alice Springs.
“Greenfield exploration is an iterative learning process. In the south-east of Sandover there is an outcropping red-bed sandstone sequence with multiple narrow but strike extensive grey shale units (reductants) containing copper oxide mineralisation. This horizon has been mapped over 20km,” Managing Director Will Robinson said.
“We drilled this first diamond drill hole into what we interpreted was a favourable structural position, at the western end of the basin targeting the first reductant. We didn’t intersect the targeted reduced unit, so we extended the hole to the basement unconformity where it intersected high grade copper mineralisation.
“This provides further evidence of highly charged copper fluids in the basin. Mineralisation has been identified in both reduced sedimentary horizons within the basin and now also at the basement unconformity. Further geophysical surveys are planned to guide the next phase of drilling.”
Sandover is located 170km north of Alice Springs and covers a major structural corridor on the southern margin of the Georgina Basin.
Field mapping and surface sampling confirmed the presence of an outcropping red-bed sandstone sequence with multiple narrow but strike extensive grey shale units containing copper oxide mineralisation.
Inspection of historical drill holes (drilled in 1968 and 1971) confirmed key geological units and processes to enable the formation of sediment-hosted copper deposits. Significantly, narrow zones of copper sulphide minerals, including bornite, have been identified in historical drill core.
This provides encouraging evidence that processes capable of forming high-grade copper mineralisation are present in the basin.
Furthermore, shale units containing the outcropping copper mineralisation at Sandover are considered to be only moderate reductants yet have precipitated considerable copper. This suggests that a highly copper charged fluid has been active at Sandover.
The remainder of the Sandover basin is essentially unexplored. The most recent diamond drilling was conducted by CRA in 1994, when two diamond drill holes were completed, 50km apart, along the northern margin of the basin.
