The output of phosphate rock since discovery in 1903 has been maintained at a steady rate and to 1972 recorded production totals 316 127 tonnes, valued at $946 206. Output during the past decade has averaged 8 000 tonnes per year. The local product suffers by comparison with imported rock in being of low grade, ranging at best from 20 to 25% P205 and containing objectionable amounts of alumina and iron oxides with R203 contents from 5% to 25% at all deposits. Selected materials, have been used in manufacture of super phosphate and experiments attempt to separate iron oxides and alumina by washing, gravity separation and flotation. Alternative modes of utilisation, including a source from which, elemental phosphorous or phosphoric acid might be recovered have also been considered. Finely ground rock when applied directly to the soil has proven to be an effective fertiliser in high, rainfall areas although the phosphate does not become fully available until three to four years after application. Current output is utilised in fertiliser preparations without chemical treatment. The Broken Hill Pty. Co. Ltd. has used rock from Tom's deposit (9 km from Kapunda) and Myponga for production of high phosphorous pig iron. The search-for phosphate in South Australia was intensified during three periods when overseas supplies were curtailed. The occurrence, production and utilisation of rock phosphate during the period to and including World War I has been detailed by Jack (1949) World War II occasioned a second phase of investigation when the government, in collaboration with the British Phosphate Commissioners, undertook a programme of testing that included drilling of a number of deposits. The most recent phase involved government and private companies in re-appraisal of the known deposits and search in new environments, during the period 1957 to 1968.