Gold exploration using groundwater in Western Australia

The use of groundwater geochemistry to explore for Au mineralisation has faced some challenges. For this type of mineralisation, the best pathfinder element is Au itself. However, the analytical technique for precious metals including Au and Ag has a relatively low sensitivity, in particular for brackish to saline waters. Medium to high salinity waters need to be diluted before analyses, leading to even lower Au concentrations and more samples below detection thresholds. Here, we present methods where a pre-concentration step is added by using activated carbon sachets that adsorb and concentrate the precious metals of interest from the water sample. This approach was used during a regional survey in the Northern Yilgarn Craton, as well as on several smaller case studies, to determine the potential of groundwater geochemistry in identifying Au mineralisation at depth. Supplementary material: https://doi.org/10.6084/m9.figshare.c.6454122