Schedule 6 Final Report: Geophysics and Drilling Collaborations Program 2024, Round 17 EL30015

Abstract

This study was co-funded under the 'Brownfields Diamond drilling' category of NT Government's Geophysics and Drilling Collaboration Program. The study comprised of a single deep diamond drillhole targeting an ANT (Ambient Noise Tomography) anomaly situated between the pegmatite hosted mineral resources at Lees and Carlton within Core Lithium LTD's ('CXO's' or 'Core's') Finniss Project area. Success from recent blind targets intersected using the same methodology led to interest in conducting this program. There has been limited opportunity to drill test ANT targets, and a successful result would validate ANT as an effective method for identifying blind pegmatites, with potential applications extending beyond the Finniss Project. Diamond drill hole NMRD099 intersected several blind pegmatites, three of which displayed spodumene mineralisation with a best geochemical assay returning up to 1.2% Li2O over 1 m from 551 m. The widths of the intersected pegmatites do not account for the targeted ANT anomaly; although there is a possibility that the pegmatites are interconnected off-section. Bedding measurements and observations of younging indicators of the orientated core suggests that the stratigraphy is tightly upright isoclinally folded, displaying an anticline and syncline pair in the bottom portion of the hole. The intersected pegmatites may have preferentially utilised these zones of weakness. Velocity measurements of the drill core show lower velocity readings (~4250 m/s) from 795m to 845 m coinciding with multiple pegmatite intrusions within a dominantly phyllite with minor sandstone rock package. There is a velocity contrast between the lower velocity pegmatites and the higher velocity host phyllite-sandstone; however, this contrast is not quite so apparent from the drill core measurements as indicated by the ANT velocity model. The large low velocity zone interpreted in the ANT velocity model and tested by diamond drill hole NMRD099 has not been fully explained by the measured velocities of the drill core. As a result, the effectiveness of ANT as an exploration tool to identify concealed pegmatites cannot yet be ruled out and is still to be determined.