Sixth Annual and Final Report for the period 25 September 2013 to 23 July 2019 EL 23971 Arrla Bay 4

Abstract

Rio Tinto Exploration Pty Ltd (RTX) applied for EL 23971 (the Tenement) on the 14 of August 2003 as part of the RTX Arrla Bay Bauxite exploration project. It was later recognised as having potential for unconformity-style uranium for the following reasons: Its position in the East Alligator River uranium prime terrain; Prospective geology of the Middle Proterozoic Kombolgie Sub Group, preserving the unconformity; Conductor identified in Geoscience Australia's (GA) multi-client EM survey; Proximity to regional faults which may control mineralisation; Limited previous exploration due to difficult access conditions. The Tenement was granted on the 25 of September 2013. In October 2013, a helicopter reconnaissance sampling programme was completed over four target areas to evaluate the potential for uranium anomalism. Three soil traverses were sampled with a total length of 12 km across the higher tenor radiometric anomalies. In total, 3 rock samples, 7 stream sediment samples, 15 geobotanical samples, and 68 soil samples were collected during this programme. The data has been submitted previously (Ozturk, 2014). In October 2015, a single 2.5 km NW-SE trending line of dipole-dipole IP was conducted (Black, 2016). The data relevant has also been submitted previously. A weak chargeable anomaly was identified on the southern portion of the IP line, interpreted as potentially being minor sulphides hosted within basement or preserved Kombolgie below Cretaceous cover. A small wacker sampling program was envisaged to test the source of the IP anomaly. Challenges for timely access proved too cumbersome and did not warrant standalone work as programs on surrounding applications have not yet been granted. In the fourth reporting period (2017), 55% of the tenement area was surrendered whereby the SE corner was retained. At the start of the sixth reporting period an additional two sub-blocks were surrendered. No additional data was collected in the final reporting period. Given the low prospectivity and challenges of access, the decision was made to surrender the Tenement in full.