The drill program was designed to test structural epithermal gold targets identified from airborne magnetic, soil geochemical and ground based dipole-dipole induced polarisation surveys.
The drill holes intersected the Mountain Creek Volcanics, host unit to epithermal gold mineralisation in the region. Encouragingly the drilling intersected bands of silica, chlorite and epidote alteration believed to be indicative of the outer propylitic alteration zone of a hydrothermal system.
Petrological analysis of base metal mineralisation intersected within hole WO-Ol also showed interpreted late phase epithermal carbonate and base metal veining to be present.
Land access is still pending for Centrex to complete a fourth hole to drill test a resistive and chargeable target associated with the Devil’s Pass Fault, a dominant regional structure.
Base metals mineralisation intersected so far in the program was encountered approximately 5km SSE along this same structure associated with a resistive but non-chargeable feature.
To date assay results have not shown any significant gold mineralisation but WO-Ol has returned anomalous base metal, carbonate and quartz veinlets over a 3m length with a best result of lm at 0.3% Pb and 0.1% Cu from 34m. WO-Ol intersected very hard, siliceous layered crystal tuffs, rhyolites and porphyrytic rocks with occasional quartz and carbonate veinlets and chlorite alteration. This is thought to account for the highly resistive feature targeted.
WO-03 targeted a resistive feature associated with a subtle magnetic low within a NNE structure around 500m west of the Devil’s Pass Fault. The drilling penetration rate decreased upon intersection of the resistive anomaly and visual logging of the drill chips confirmed siliceous volcanic rock units although with less alteration than found in
wo-Ol.
WO-04 targeted both a resistive and chargeable feature at depth along the same structural trend further north. The drilling penetration rate was again progressively slower at depth due to the hard siliceous nature of the dominantly siliceous rhyolite rock units and minor granite intrusives. Minor magnetite was found in the fines portion of the drill chips and accounts for the high magnetic susceptibility common within the Mountain Creek Volcanics unit. There was no obvious explanation for the chargeable feature being targeted, although possible chlorite, epidote and minor hematite alteration was noted in drill chips.
Woolgarlo Gold Project
The Woolgarlo Gold Project is located in NSW, approximately 50km NW of Canberra and within the prospective East Lachlan Fold Belt. Historical exploration has demonstrated that epithermal gold mineralisation is present within Devonian Mountain Creek Volcanics at either end of the project area at the Mt Mylora and Sugarbag Hill prospects.
Centrex completed a high-resolution air-borne magnetic survey in 2014 between the two historical prospects, as Surgarbag Hill to the south has been interpreted to be the top of an epithermal system, and Mt Mylora in the north to be the base.
The magnetic survey results were encouraging, suggesting possible magnetic destruction along interpreted NNW trending faults thought favourable for further epithermal gold mineralisation within the target host rocks.
The overall interpretation of the magnetics indicated a central north-south trending graben feature that is in line with an epithermal model. Later EW compression has produced folding of the Devonian age host volcanics and generated prospective structural traps for remobilised mineralisation.
Centrex followed the magnetic survey with a ground based dipole-dipole IP program consisting of 7 approximately 1.5 – 2km long lines, orientated perpendicular to the structures and spaced broadly along them. The IP lines were positioned across the targets to provide vertical resistivity and chargeability profiles of the subsurface, seeking resistive anomalies associated with demagnetized fault structures, indicative of silicification often associated with epithermal gold mineralisation.
