This report presents the results of a study by the Geological Survey of South Australia (GSSA) and CSIRO Mineral Resources to investigate the magnetisations causing prominent negative polarity (‘reverse’) magnetic field anomalies in the Coompana area of south-western South Australia. The study area is covered by younger deposits of the Eucla Basin, with no surface exposure of the rocks carrying the reverse remanent magnetisation, or of the basement rocks into which they are intruded. The geological event giving rise to the rocks carrying this distinctive reverse magnetisation clearly involved the heating and melting of a large crustal volume, with the strong possibility of associated mineral systems. Discovery and understanding of those mineralisation systems will require understanding of this extensive event, presently only known through its magnetic field expression (soon to be augmented with a comprehensive gravity investigation, and a regional drilling program). We hope, from recovery of magnetisation directions, to recognise similarities or differences between magnetisations across the area which might allow us to correlate different intrusive bodies, and to investigate possible correlation with reverse magnetisations known from deep beneath the Officer Basin in eastern West Australia, and from Giles Complex rocks in the Musgrave Province to the north. The magnetisation direction estimates are also required for any source modelling in support of drill testing of the anomalies, as use of an incorrect magnetisation direction will result in corresponding spatial errors in the source models. More than forty magnetic anomalies have been investigated in this study. When drill core samples from holes in the planned drilling program become available for rock magnetic and palaeomagnetic studies, we hope such studies will allow extrapolation of what has been learnt from those magnetised rocks to the much larger number of untested bodies present across the complete province. At that time too, the magnetic field interpretation presented here should be re-visited to integrate the new magnetic source data with it and with the new gravity survey data, to give a better understanding of intrusions affecting potential mineralisation systems.