King River Project EL 5891, Relinquishment report 2004

Abstract

This report describes all exploration work undertaken within that portion of Exploration Licence 5891, which was relinquished on the 12 May 2004. A total of thirty five blocks was surrendered on that date. The licence area is located in northwestern Arnhem Land and was granted on the 13 May 1996 for a period of six years. A two year renewal was granted in March 2002 for the period ending on May 12 2004. The exploration program was initially managed by PNC Exploration Australia Pty Ltd (1996 to 1999 inclusive) and then by Cameco Australia Pty Ltd on behalf of the Nadjinem Joint Venture partners, Cameco Australia Pty Ltd, PNC Exploration Australia Pty Ltd and the Nadjinem Aboriginal Corporation. PNC withdrew from the JV in 2001. The primary exploration target is for unconformity related uranium deposits similar to the nearby Ranger, Jabiluka and Koongarra deposits and the now depleted Nabarlek mine. Exploration activities over the eight year period comprised airborne surveys, geological mapping, stream sediment and rock sampling. Gneiss and migmatite of the Nimbuwah complex are unconformably overlain by the mid-proterozoic Kombolgie Subgroup, which in this region is represented by the basal Mamadawerre sandstone. Cretaceous remnants cover the basement rocks in places. Younger intrusives comprising the Oenpelli dolerite intrude both the Nimbuwah and Kombolgie. The focus of the exploration strategy is the discovery of unconformity-related uranium deposits. The nearby economic deposits at Ranger, Jabiluka, Koongarra and the now depleted Nabarlek Mine serve as models for this strategy. The presence of gold, palladium and platinum in these deposits plus the economic gold-platinum resource at Coronation Hill in the South Alligator Valley, indicates an additional potential for this deposit style. The King River-style of mineralisation has varying contents of these elements. The principal area of exploration interest was the Kombolgie sandstone block termed 'Ralph's block'. The southern side of this outlier was potentially prospective due to a combination of anomalous labile uranium and gold results, which appeared to be related to a zone of silicification and quartz veining. The latter is coincident with a major regional structure, the Anuru Fault zone, which extends southwards and can be traced across the other King River tenements. Exploration over this area comprised several seasons of stream sediment and rock sampling, geological mapping and ground radiometrics. The conclusion drawn was that although there is some elevated geochemistry associated with the structural zone identified in the sandstone, the levels of uranium-gold anomalism combined with the low level surficial radiometrics and lack of widespread alteration pointed to a very localised feature of minimal interest. Airborne anomaly ANG9 located north of the sandstone outliers was originally prospected by Union Carbide in the early 1970s with only minimal work performed. The Joint Venture reinvestigated this anomaly, which manifests as a prominent northwest trending fault comprising intensely quartz veined and silicified basement rocks. Rock sampling and radiometric traverses failed to locate anything of interest associated with the fault zone and no work was performed.