Round 16 Geophysics and Drilling Collaborations program Final Report Sandover Diamond Drilling EL 32695

Abstract

The Sandover Project is located approximately 170km North of Alice Springs and approximately, 250km South of Tennant Creek. The Project sits on the Neoproterozoic-Palaeozoic Southern Georgina Basin, which unconformably overlies Meso and Paleoproterozoic rocks. The project is on the Alcoota, Mount Peake and Barrow Creek 1:250,000 scale NTGS geological map sheets. The Sandover project tenure is considered prospective for sediment-hosted copper mineralisation. The major elements of a sediment-hosted copper system are present within the Sandover Basin. Rift phase Neoproterozoic sediments of the Georgina Basin are juxtaposed against crystalline basement (Arunta block). There is recorded presence of evaporites, reduced stratigraphic units, and red-bed sequence within the Sandover Basin stratigraphy. Copper anomalies are known in the area both from outcrops (particularly the Mt Skinner area) and drillholes. Encounter was granted funding for the Sandover Diamond Drilling Collaboration Program. The program consisted of one stratigraphic drillhole - ESA001. The hole was designed to test basin stratigraphy in an area of structural confluence where an interpreted oblique (approximately NE-SW) orientated cross cutting lineament extends across the basin and intersects a major NW-SE trending lineament. The hole aimed at testing the possible extension of the Elyuah Formation (interpreted to be a significant reductant) to the Northwestern part of the Sandover Basin, and also to investigate potential fluid flow occurrences along a regional structure. ESA001 stratigraphic diamond hole was drilled in November 2023. The hole reached a TD of 668.7m intersecting sediments of undifferentiated Phanerozoic Basin, Cambrian sediments of the Narpa Group, the Neoproterozoic Mopunga Group and 34m of granitic and metamorphic basement. ESA001 provided information and insights into the structure and stratigraphy in the Northwestern part of the Sandover Basin. The hole did not confirm the extension of the prospective Elyuah Fm, which was not intersected, and does not appear to be present in the northwestern part of the Sandover project area. Hydrothermal sulfide alteration was observed at the basal unconformity with a copper enriched interval of 10-20cm thickness at the basement-basin interface.