Round 18 Resourcing the Territory Supplejack Ground Gravity Survey Final Report EL 33765, EL 33766, EL 33767

Abstract

In 2025, Iluka Resources Ltd completed a large-scale ground gravity program across the eastern part of the Supplejack Project area, located approximately 600 km NW of Alice Springs, Northern Territory. A total of 5,791 new ground gravity stations were acquired at a range of spacings, including 400 x 400m, 200 x 200m, 200 x 100m, 100 x 100m, and 50 x 50m. The survey area covers the southeastern margin of the Birrindudu Basin, where the unconformity between the Granites-Tanami Orogen (GTO) and the overlying Paleoproterozoic Birrindudu Basin is mostly concealed beneath shallow Tertiary and Quaternary cover. The project is currently being explored for hydrothermal unconformity-related rare earth element (HUREE) deposits, with a focus on targeting major NW- to NNW-striking fault zones. The gravity data proved highly effective in mapping major fault zones and assisting with the delineation of concealed units of the Paleoproterozoic Birrindudu Group and the Supplejack Sandstone. The survey also identified areas of elevated gravity and magnetic response, interpreted to reflect shallow occurrences of the Mount Charles Formation.