An area extending along the Marree - William Creek - Oodnadatta Track, some distance to the west of Lake Eyre South and centred 140 km north of Olympic Dam, has been explored for possible economic buried Mesozoic sandstone-hosted (Kazakhstan style) uranium deposits which may have formed in the Great Artesian Basin (GAB) / Eromanga Basin aquifer section lying below the Cretaceous Bulldog Shale aquiclude. Of particular interest was the line of mound springs and groundwater bores that extend inside EL 4640 between Coward Spring and Strangways Springs: these were considered to be possible leakage points arrayed along a basin tapping fault structure having anomalous indications of uranium, as described from older published data. During the first year of tenure, the licensee collected water samples from bores and springs to check on the temporal persistence of reported highly anomalous uranium values noted from a Geoscience Australia-CSIRO database containing hydrochemistry information for >800 groundwater samples which they had collected from the GAB and analysed in 1985; the majority of their uranium anomalous samples were located in the area that lately was taken up as EL 4640 for the purpose of conducting a further investigation. Accordingly, in 2011 the licensee had the Amdel laboratory analyse a new set of 25 mound spring outflow and bore water samples, in addition to 6 small rock samples obtained from spring evaporate deposits. It was observed while carrying out the prior field reconnaissance work that the carbonate mound spring deposits at Strangways are quite anomalously radioactive, both on airborne radiometric survey images and when checked with a scintillometer on the ground. However, the latest sampling did not confirm the presence of anomalous dissolved uranium in the spring or bore water, and therefore Callabonna Resources thinks that the government database is most likely in error. Nevertheless, the high background radiometric counts in fossil carbonate deposits from the Strangways mound spring area were confirmed. During the second and final licence year, no further work was done and the licence was not renewed, because Callabonna Resources was unable to attract a joint venture company that would fund the expensive next stage of exploration, namely, seismic data acquisition needed to map the subsurface structures that might control any uranium deposition.