Australian sandstone-hosted uranium deposits

Abstract

Australia’s sandstone-hosted uranium deposits occur in sedimentary basins of Carboniferous, Cretaceous and Tertiary age; these include some of Australia’s largest and highest grade uranium deposits. The conventional model for sandstone-hosted uranium deposits has proved robust and a predictive model leading to the discovery of many deposits in Australia. The location of deposits is strongly influenced by the presence of Mesoproterozoic and Archaean age leachable uranium-rich source rocks in the headwaters of channels draining into basins developed in the Northern Territory, Western Australia and South Australia. Australia’s production of uranium from sandstone-hosted deposits is limited to two in-situ leach operations and is relatively minor when compared to production from Kazakhstan and the USA. Nevertheless, Australia has a large inventory of uranium resources in 19 undeveloped sandstone-hosted deposits, amounting to 123 kt U3O8. The average grade of all 21 Australian deposits that have resources is 0·15% U3O8. Tertiary palaeochannels host the greatest number of deposits and include the largest and highest grade deposits. The Callabonna Sub-basin in South Australia is the most richly endowed basin, accounting for 62·4 kt U3O8, being 38% of Australia’s sandstone-hosted resource inventory. Australia remains highly prospective for the discovery of new palaeochannel hosted uranium deposits, with regional airborne geophysical surveys likely to be of great assistance in continuing to define palaeochannel systems that may host uranium in basins draining uranium rich source rocks.