CORE Geophysics and Drilling Collaborations Round 11 2018 Cow Lagoon EL 26831

Abstract

Diamond drillhole NB18DD050 was drilled between the 21st August and the 3rd September, 2018 as part of Round 11 of the Northern Territory Geophysics and Drilling Collaborations Program. The Cow Lagoon prospect is located 32 km north north-west of the McArthur River Mine, just north of the 2002 Geoscience Australia seismic line. The rationale for the drillhole was based on a favourable structural position for epigenetic mineralisation indicated by the fold and thrust seismic interpretation and an anticline in NTGS surface mapping. Nearby historical exploration has focused on the eastern side of the thrust, encountering thick Lynott Fm sediments and a deep facies Barney Creek Fm, both exhibiting gas shows. The presence of hydrocarbons and a favourable structural setting on the western side of the thrust, with potential for carbonaceous strata of the Lynott Fm and Barney Creek Fm, made this an attractive target for Century-style epigenetic base metal mineralisation. NB18DD050 is interpreted to have drilled through thin cover into Lynott Formation sediments before passing through a 20 m thick interval of Reward Dolomite and into Barney Creek Formation. The Barney Creek Formation became strongly carbonaceous and variably pyritic from 369 m onwards and was commonly brecciated. Occasional sphalerite blebs were observed from approximately 190 m to approximately 600 m depth and were often associated with veins, concretions and nodules. The hole was terminated at 695 without testing the base of Barney Creek Formation. The decision to terminate the hole was based on the interpretation that the hole was no longer drilling down stratigraphy but rather alternately drilling down a steep anticlinal limb and into the brecciated hinge of the fold. NB18DD050 provides supporting evidence towards the potential for epigenetic mineralisation in the Cow Lagoon area. The presence of texturally late blebby sphalerite and evidence for high volumes of fluid flow within carbon rich pyritic lithologies is encouraging. NB18DD050 was unable to test the entire Barney Creek Formation due to local structural complexity and potential still exists in the area.