An area of 5 square miles around the Last Chance Mine, Peake and Denison Ranges was reserved from the operation of the Mining Act in February, 1969 to permit the investigation by the Geochemical Exploration Section of a reported uranium/copper occurrence. The Last Chance Mine was worked briefly for copper in 1915-16. The presence of uranium in the deposit was not detected until August 1966 when B.E. Milton (Senior Geophysicist) located a source of radio-activity in the open pit, and recorded a series of peaks on a number of scintillometer traverses north and south of the mine. North Broken Hill Limited carried out regional and detailed geochemical surveys in this Special Mining Lease over the Peake and Denison Ranges between September 1966 and December 1968. The only mineral occurrence within the area of the present Reservation, located by this survey was the mine deposit. A soil survey over the deposit revealed a small linear copper anomaly to the north and south of the mine. It was felt that stream sediment sampling could be profitably repeated using a shorter sampling interval. Soil and radiometric surveys would be carried out in any area giving anomalous stream sediment analyses.