An extensive search for economic iron ore deposits has been made on Eyre Peninsula by the South Australian Government. Originally the search was made in the Middleback Range area, which was until recently the source of all of the iron ore used in Australia. After that area became sequestered through the granting of an exploration indenture to BHP in 1958 by the Government, the prospecting was performed elsewhere, using data obtained by an inaugural BMR high level airborne magnetic survey as the basis. Two regional magnetic anomalies located on the eastern part of the peninsula, and three located on its western part, are briefly discussed. A detailed description is given of the Government's investigation of the Warramboo aeromagnetic anomaly in central Eyre Peninsula, initially using low level aeromagnetic survey plus ground magnetic and gravity methods. An exploratory drilling programme was subsequently laid out, and a brief summary of the results is given, abstracted as follows: - a drilling programme of 133 holes for 13,163 feet was undertaken by the Mines Department at Warramboo, commencing in May 1961, to test peak magnetic and gravity anomalism indicated by 125 line miles of detailed ground surveys. The majority of the holes were rotary percussion drilled, and many had diamond cored tails. Three of the holes were fully diamond cored (WD1 - WD3). The deepest penetration achieved was 928 feet in hole WD2. All of the drillholes encountered iron-bearing rocks, and thereby defined a deposit extending for 5.5 miles east-west and for 600-1000 feet north-south, down to a depth of 886 feet. The drill cores recovered from the holes were logged for specific gravity and magnetic susceptibility, and compared in relation to assay results to see if the geophysical responses could act as a proxy for iron ore grade. Later work commenced in the Kopi area, south of Warramboo, is briefly mentioned.