Eocene fluvial sediments underlying the coastal plain immediately north of Port Broughton have been explored for possible economic buried occurrences of palaeochannel-hosted sedimentary uranium, as part of a regional programme being conducted by Areva along the eastern shoreline of northern Spencer Gulf, targeting the Tertiary to Recent Pirie Basin. Licensee Afmeco considered that this geological setting, situated right above the tectonically long-active Torrens Hinge Zone, had the potential to host sandstone-hosted uranium mineralisation in Eocene palaeochannels, that would probably be similar to that of the recently found Mullaquana deposit located on the opposite side of Spencer Gulf. Afmeco’s initial conceptual model had uranium leaching from Hiltaba Suite volcanic and plutonic rocks (source beds) that were/are exposed in the Stuart Shelf, north of the Spencer Gulf, and entering the upstream portion of the Tertiary palaeodrainage system (transport), with reduced Eocene fluvial sand units in the southern downstream section potentially precipitating this uranium (trap). In 2010, the Mullaquana uranium deposit was believed to have a similar source for its uranium. Later on, though, it became apparent to Afmeco/Areva from emerging public information that the uranium mineralisation at Mullaquana is actually intimately associated with a uraniferous Hiltaba Suite granite present directly beneath the palaeochannel hosting the deposit. Following another extensive review it then made of the regional geology and historical drilling data, Areva found that uranium-rich basement rocks, specifically the Tickera Granite (Hiltaba Suite) are in close proximity to EL 4505 (~7 km to the south), and thus could perhaps have similarly acted as a proximal source for uranium emplacement within Tertiary palaeochannels. Excellent reducing environments appeared to exist in the Port Broughton - Port Pirie region, with reports of several coal deposits and an abundance of organic matter occurring within the sediments. Previously, several minor uranium geochemical anomalies had been recorded within Tertiary sediments located to the south-east of Areva's current project area. No field work was conducted on the subject licence during its first three years. Plans to acquire scout traverses of gravity readings across the tenement to outline the thickest palaeochannel sections were abandoned during 2011, in favour of carrying out broadly spaced exploratory drilling to define the channel geometry and distribution and to look for redox interfaces in the target Kanaka Beds. During November-December 2013, 19 vertical rotary mud exploratory holes with a total penetration of 1540 m were drilled alongside main roads crossing the licence area, at sites on high ground well removed from the marshy coastal wetland environment. The results of this drilling were described as follows: - the drilling demonstrated the existence on EL 4505, but in its south-eastern corner only, of a small part of a main Tertiary channel feature that had been incised into Neoproterozoic metasedimentary basement; - observations gleaned from the drilling indicate that it was a NE to SW running channel system; - all basement rocks that were encountered are Adelaidean metasediments – it is believed that any Mesoproterozoic granitic basement will be absent from immediately beneath the Tertiary; - reductants such as organic matter are abundant within the Tertiary fluvial sequence, but they are mostly distributed outside of the main channel, in inferred palaeo-swamps; and - minor log-interpreted radioactivity anomalies (max 110 ppm eU3O8) were detected at the interface between an overlying oxidised, carbonate-rich formation (?Melton Limestone) and the underlying reduced Kanaka Beds, or at the interface between sands and carbonaceous clays. As the interpreted main flow direction of the incised palaeochannel is not consistent with a source-transport-trap model, and because drilling had confirmed the expected absence of uraniferous source rocks lying close below or next to Tertiary units, the hybrid original / Mullaquana analogue revised Project exploration model was downgraded. Consequently, an application to surrender EL 4505 was submitted on 3/4/2014.