The Tanami region, located approximately 600 km northwest of Alice Springs in the Northern Territory, is regarded to be highly prospective for the discovery of large, high grade unconformity style uranium deposits. Until now, little exploration for uranium has been able to progress on Aboriginal Freehold Land.
Unconformity style uranium deposits are high grade, high profitability uranium deposits. Major fields of this style are the Athabasca Basin in Canada and the Alligator Rivers Uranium Province, in the Northern Territory (e.g. Ranger uranium mine). These deposits form within and above Proterozoic graphite and iron bearing basement rocks that are immediately unconformably overlain by thick sandstone sequences.
Stratigraphic comparisons between the Tanami and Athabasca Basin and Alligator Rivers Uranium Provinces show similar stratigraphy and age relationships. In the Tanami the important rock units are the Dead Bullock Formation specifically the graphite and iron rich units, underlying the Gardiner Sandstone.
Many unconformity style uranium deposits contain gold. Thus the target rocks may host gold and uranium.
Suplejack and Talbot North contain the prospective Gardiner Sandstone, lying in unconformable contact with favourable (graphitic and iron rich) units of the Tanami Complex. At Suplejack no surface uranium anomalies are present as the tenement is blanketed by 40–80 metres of Cambrian basalt. At Talbot North detailed interpretation of the regional magnetics has identified areas of significant magnetic destruction, coincident NW–SE trending major structures, favourable host rocks and significant radiometric anomalies attributed to uranium and thorium. Previous uranium exploration in 1973 confirmed minor amounts of uranium in surface rockchips.
As an aid to targeting of drillholes, an airborne EM survey will be conducted to identify areas of suitable hosts for unconformity style mineralisation associated with faults within the Gardiner Sandstone.