Stream Sediment Geochemical Study for gold target in Malua River Prospect, Enrekang, South Sulawesi

Abstract

In order to get a better insight into gold occurrence in the western flank of Latimojong Mountain, a field work study campaign focusing on stream sediment sampling activity was completed along Malua River or locally called as Salu (River) Malua in Curio and Malua Area, Enrekang, South Sulawesi.  Stream sediment study is aimed to investigate the possible sources of anomalous element particularly gold concentration within the studied area. In addition, the project was to delineate ground within the study area that shows economic potential for gold mineralization. A total of 32 stream sediments samples were collected during the field work and 20 samples were sent to laboratory and analyzed for gold and other base metal elements (Cu, Pb, Zn, Ag, As, Sb, Mo). Au was analysed using Fire Assay (FA) method, whereas Cu, Pb, Zn and Ag method were analysed using Atomic Absorption Spectrometry (AAS) method and As, Sb and Mo were analysed using X-ray fluorescence (XRF) method. Based on sample distribution and the occurrence of gold, a threshold of 10 ppb Au is considered. Two samples collected from LP20 and LP32 returned gold value in threshold range (7 – 14 ppb). Other sample show lower value (less than 0.5 ppb). The result suggests a single population density attributed to the metasedimentary rocks in the Latimojong Formation (eastern to northeastern part of the concession). Two anomalous target zones namely Buntulimbong and Buntukaok and tentatively combined as Patongan anomaly in the northeastern part of the concession have been delineated for further work. Interpretation of the result suggests that mineralization appears to be associated with lithological boundary between Toraja Formation and Latimojong Formation. The result of the survey indicates that Curio-Malua concession has good exploration potential and significant potential for lode gold mineralization within a favorable geologic terrain.