The pastoralists had scarcely established themselves on their runs when the solitude of interior Otago was interrupted by the entry of tens of thousands of alluvial gold miners, an event which ensured Otago's supremacy in population and wealth among the provinces. The first vital discovery was made by Tasmanian-born Gabriel Read in the Tuapeka district in May 1861, and by the end of the year an estimated 14,000 people were on the diggings. During the next winter the prospectors Hartley and Reilly got phenomenal yields from the river beaches of the Dunstan Gorge near Cromwell, and news of their success triggered off a mass movement of diggers into the dry heart of Central Otago in the spring of 1862. In the summer the tide of mining settlement pushed into the alpine valleys of the lakes district. Later in 1863 it surged back eastwards into the Manuherikia Basin, the Maniototo Plains, and the Taieri Gorge, and the provincial gold yield reached its peak of 600,000 oz. Early in 1864 the pattern of gold discoveries was virtually complete and the maximum goldfields population of about 22,000 had been reached. In this vigorous, migratory society, males outnumbered females by five to one. Although the population was predominantly of British origin, the Irish representation was strong and most miners had spent some years on the Victorian diggings. The exodus to the Marlborough diggings in 1864 and to the West Coast in 1865 reduced the Otago goldfields population to 10,000 by 1866, but on the heels of the departing Europeans came Chinese miners to rework abandoned ground; by 1871 there were some 2,600 Chinese in the province. During the 1870s and 1880s gold mining was maintained by hydraulic sluicing, but yields fell steadily, despite increasing investment in water races and machinery. At least 80 townships originated as mining camps in the 1860s and those located at river crossings or the junction of routeways survived as rural services centres. But the most impressive results of the golden decade were reflected in Dunedin with its imposing commercial and public buildings and its rapid population growth. From a straggling village it grew to some 16,000 people in 1864, and about 24,000 in 1874.