Gold rushes helped spur waves of immigration that often led to the permanent settlement of new regions. Activities propelled by gold rushes define significant aspects of the culture of the Australian and North American frontiers. Jets of water at a placer mine in Dutch Flat, California sometime between 18 Gold rushes occurred as early as the times of the Roman Empire, whose gold mining was described by Diodorus Siculus and Pliny the Elder, and probably further back to ancient Egypt.Īt a time when the world's money supply was based on gold, the newly-mined gold provided economic stimulus far beyond the goldfields, feeding into local and wider economic booms. Within each mining rush there is typically a transition through progressively higher capital expenditures, larger organizations, and more specialized knowledge. ![]() They may also progress from high-unit value to lower-unit value minerals (from gold to silver to base metals).Ī rush typically begins with the discovery of placer gold made by an individual. At first the gold may be washed from the sand and gravel by individual miners with little training, using a gold pan or similar simple instrument. Once it is clear that the volume of gold-bearing sediment is larger than a few cubic metres, the placer miners will build rockers or sluice boxes, with which a small group can wash gold from the sediment many times faster than using gold pans. Winning the gold in this manner requires almost no capital investment, only a simple pan or equipment that may be built on the spot, and only simple organisation. The low investment, the high value per unit weight of gold, and the ability of gold dust and gold nuggets to serve as a medium of exchange, allow placer gold rushes to occur even in remote locations.Īfter the sluice-box stage, placer mining may become increasingly large scale, requiring larger organisations and higher capital expenditures. Small claims owned and mined by individuals may need to be merged into larger tracts. Difficult-to-reach placer deposits may be mined by tunnels. Water may be diverted by dams and canals to placer mine active river beds or to deliver water needed to wash dry placers. ![]() The more advanced techniques of ground sluicing, hydraulic mining and dredging may be used. Typically the heyday of a placer gold rush would last only a few years. ![]() The free gold supply in stream beds would become depleted somewhat quickly, and the initial phase would be followed by prospecting for veins of lode gold that were the original source of the placer gold. Hard rock mining, like placer mining, may evolve from low capital investment and simple technology to progressively higher capital and technology. The surface outcrop of a gold-bearing vein may be oxidized, so that the gold occurs as native gold, and the ore needs only to be crushed and washed (free milling ore). The first miners may at first build a simple arrastra to crush their ore later, they may build stamp mills to crush ore at greater speed.
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