The South Alligator group of tenements consists 1,541.8 sq km and is situated in the Pine Creek Orogen and the McArthur Basin. The project area hosts extensive moderate to strong radiometric anomalies surrounded by uranium, base metal and gold prospects. The project areas are considered favourable to host vein-type deposits in which uranium minerals fill cracks, veins, fissures, pore spaces, breccias or stockworks, associated with steeply-dipping fault systems. Within the Edith River area uranium occurrances are related to steeply dipping north-northwest-trending shear zones within the greisenised Tennysons Leucogranite. Shear zones are up to 100 m wide and consist of a series of parallel quartz-filled shears (Kruse et al 1994). Mineralisation also occurs within tension fracture systems on the margins of shear zones. Autunite and minor torbernite are the main ore minerals, which occur as disseminations in haematitic breccia and coatings on joint and fracture planes (Gardner 1953a). Mineralisation at these prospects was only investigated to a depth of 10 cm and the primary uranium minerals are not known.
The Lambell Fault located in the east proportion of EL’s 26259 and 26260 represents a major structural target . The Grace Greek Granite geological model can be used as per the Edith River uranium prospects ie shear zones hosting uranium minerals within granitic intrusions. Other faults proximal to the Grace Creek Granite may represent high grade vein style uranium targets also.
Further work should also be concentrated on the ‘”South Anomaly” prospect to define the source of the radon. Geological mapping of the Kombolgie Sandstone and the fractured anticlinal axis should be targeted as a potential structure hosting uranium mineralisation.