As part of a regional evaluation of the variably exposed Lower Proterozoic metasedimentary sequence on eastern Eyre Peninsula for possible economic pitchblende mineralisation, portion of a semi-detailed airborne radiometric/magnetic survey was flown inland from Port Neill. Ground follow-up of the airborne anomalies by scintillometer surveys and geological mapping at 1:25,000 scale indicated that very low primary uranium anomalism is associated with the Katunga Dolomite, but also that other, very intense anomalies observed in the Driver River and Dutton River valleys are associated with local zones of surface seepage of groundwater from Tertiary aquifers, wherein uranium mineralisation is presumably being actively leached. The known U-anomalous alkaline syntectonic granites are too deeply buried in these areas to provide a direct source for the strong alluvial anomalies, and now it is thought that subsequent faulting and weathering processes could not have remobilized and concentrated their uranium into the overlying Tertiary strata in quantities sufficient to be economic.