Interest in gold in W.A. increased following the 1849 California and 1850's Victorian rushes. A rich find made by Arthur Bayley and William Ford during 1892, in Coolgardie, inspired a small rush. A large amount of gold (over 500 oz) was initially found on Bayley's Reward lease above a quartz reef. Within a month, 3000 oz had been found by 400 prospectors. Soon after, in June 1893, Patrick Hannan, Tom Flanagan and Daniel O'Shea discovered a rich deposit of gold at Mt. Charlotte, Kalgoorlie. This initiated a rush resulting in the discovery of the Kalgoorlie-Boulder "Golden Mile". From here, gold exploration spread throughout the state. The introduction of ground cancelling metal detectors to Australia in 1974 created renewed interest in prospecting that, together with the high price of gold, led to the prospecting boom of the late 1970's and early 80's. The largest nugget ever found in W.A. is the Golden Eagle by Larcombe at Larkinville in 1932. It weighed 1135 oz. Alluvial and reef gold occurs in the Yilgarn, Pilbara and Kimberley districts. Approximately 95% of the states gold production has come from the Yilgarn district, exceeding the Pilbara and Kimberley by far.