As part of the SADM iron exploration programme in South Australia, geophysical and drilling investigations have been undertaken on the Warramboo Anomaly, the largest elongate asymmetrical aeromagnetic anomaly in the State outside of the Middleback Ranges. This feature is about 15 miles long E-W by 2 to 3 miles long N-S, and has 3 sub-parallel peaks running along its length, suggesting 3 separate zones or beds. Initially, 45 ground magnetic and gravity traverses have been laid out spaced at 1000 foot intervals E-W and extending for 2.5 miles N-S, to cover an area of approximately 20 square miles. The highest magnetic readings obtained reach 1200 gammas above background, with corresponding gravity maxima rising to 2 mGal above background. Drilling carried out to date along 11 of the survey traverses (133 holes, total 13,163 feet) has intersected an ?Archaean medium grade metasedimentary iron formation extending over 5.5 miles E-W, 600 to 1000 feet N-S and to depths of 886 feet, with essentially all holes testing magnetic and gravity peaks having penetrated iron-bearing lithologies. The eastern half of the anomaly and its western end have not yet been drilled. Of the diamond cored holes completed, substantially all have been assayed at 20 foot intervals, with roughly 24% of the samples returning over 20% Fe. Subsequent metallurgical tests have shown that the iron formation contains coarse grained magnetite which can easily be beneficiated using simple methods. This factor alone is significant enough to demand that testing of the deposit be continued until all technical and geological aspects have been considered. The location of the deposit astride an existing water pipeline and a railway, and only 118 miles distant from an excellent deepwater port, is such that development for export is assured if tonnage and grade are adequate.