Since the days of early settlement in South Australia mineral production from Yorke Peninsula has made an important contribution to the wealth of the state. Firstly, with the discovery and mining of copper in the Moonta Wallaroo district early in 1860, later the utilization of gypsum for plaster manufacture in the Yorketown district in 1870, and the commercial production of salt in 1890 from the numerous salt lakes abounding on Southern Yorke Peninsula, whilst latterly large scale industrial usage is made of the extensive limestone and dolomite deposits for Portland cement manufacture and in the steel manufacturing industry. It is estimated that the nominal value of the principal minerals won to date is in excess of £30,000,000. A comparison of the output of the principal minerals over the ten year post war period 1948 to 1958 reveals considerable expansion, in most branches of the industry; in some cases output has been more than doubled, as shown in the accompanying table.