The role of airborne geophysics in facilitating long-term outback water solutions to support mining in South Australia

Abstract

Mining and energy development in South Australia's far north is set to have significant consequences for the water resources of the region. These sectors generate significant economic value to the State and their support remains a priority for the government. The scale of the planned developments and the potential from current exploration programs facilitated by the South Australian Government through PACE Program will result in a substantial increase in infrastructure requirements, including access to water resources and Aboriginal lands for potential mine developments. Increased demand for water and in particular groundwater is compromised by the limited knowledge we have about these resources. This includes information about their character, variability, sustainability and their relationship to environmental and cultural assets, which is most notable in the priority areas for development. There is a recognised need to develop this knowledge so that water is not a limiting factor to development. In this paper results from the Goyder Institute's Long-Term Outback Water Solutions (G-FLOWS) Project are presented. Particular reference is made to work completed in the Musgrave Province. It illustrates the role of local scale AEM, acquired for exploration, and regional scale airborne magnetics in helping develop a hydrogeological conceptual model for the Province. The AEM data reveal a complex, extensive inset palaeovalley system which contains groundwater of variable quality (2000 - 4500 mg/L TDS). Examination of their location against the regional magnetics indicates a strong lithostructural control on their orientation and distribution. If mineral resources were to be developed in the area, these groundwater systems would represent the best option for water supply. A regional scale water resource map, based on information gleaned from the geophysics, existing hydrogeological and digital elevation data, is presented that provides a framework for groundwater resource determination when/if mineral deposits were to be mined in the region.