EL 7190 (Roper River), first annual report to 13-03-1992

Abstract

Exploration for diamonds, base metals and gold was carried out over EL 7190 in 1991. Reconnaissance heavy mineral stream sediment sampling for diamonds was completed, and possible kimberlitic indicator minerals, mainly being spinels, were obtained from a number of samples draining breakaways of Cretaceous rocks. Infill samples were collected around the north-central licence area around Cretaceous rocks, which confirmed the anomalous nature of a number of catchments. Rare kimberlitic compositions were obtained, but results were not encouraging enough to warrant further diamond exploration. The Cretaceous cover is possibly a secondary source of the spinels. Particulate galena and barite were noted in heavy mineral concentrates from samples collected in the northeast of the licence. Follow up geochemical investigations determined that a spatial relationship occurs between barite and galena, and enhanced Cu, Pb and Zn values exist in a drainage system in the north-east of the licence. Further work for base metals is planned.