Site investigations of part of the coastal area south of Whyalla were undertaken by BHP Minerals Div. as part of overall studies addressing the possibility of expanding their Whyalla Salt Works. Field inspections of the area behind Murninnie Beach and laboratory permeability testing of coastal soil samples obtained by block and tube sampling have shown that the top 6 feet of the soil profile is relatively pervious, while the clay subsoil occurring below this is comparatively impermeable. The main natural seepage direction is believed to be towards the sea. However, by simulating in the laboratory the likely physical effects of conditions of bank construction upon the samples collected, it is concluded that such seepage can be largely overcome by the envisaged mode of construction of the seaward retaining bank of the proposed salt pond.