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Placer mining (ˈplæsər) [ 1 ] is the mining of stream bed deposits for minerals. [ 2 ] This may be done by open-pit mining or by various surface excavating equipment or tunneling equipment. Placer mining is frequently used for precious metal deposits (particularly gold) and gemstones, both of which are often found in alluvial deposits ...
v. t. e. The California gold rush (1848–1855) was a gold rush that began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. [1] The news of gold brought approximately 300,000 people to California from the rest of the United States and abroad. [2] The sudden influx of gold into the money ...
Gold Dredge, Klondike River, Canada, 1915. The Yankee Fork dredge near Bonanza City, Idaho, which operated into the 1950s. A gold dredge is a placer mining machine that extracts gold from sand, gravel, and dirt using water and mechanical methods. The original gold dredges were large, multi-story machines built in the first half of the 1900s.
The earliest recording of gold mining activity in Virginia began about 1804 as placer mining, followed quickly by lode mining. Mining continued unabated until the onset of the California Gold Rush, at which point most serious speculators moved west.
Hydraulic mining. A miner using a hydraulic jet to mine for gold in California, from The Century Magazine January 1883. Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment. [1] In the placer mining of gold or tin, the resulting water-sediment slurry is directed through sluice ...
As with most gold rushes, the California gold rush started with the discovery of placer gold in sands and gravels of streambeds, where the gold had eroded from hard-rock vein deposits. Placer miners followed the gold-bearing sands upstream to discover the source in the bedrock. This source was the "mother" of the gold in the river and so was ...
The resulting gold rush resulted in more placer discoveries, including those at Virginia City in 1863, and at Helena and Butte in 1864. [32] In 1867, the Atlantic Cable Quartz Lode was located. The Butte district, although mined primarily for copper, produced 2.9 million ounces (91 tonnes) of gold through 1990, almost all as a byproduct of ...
Jets of water at a placer mine in Dutch Flat, California sometime between 1857 and 1870. Within each mining rush there is typically a transition through progressively higher capital expenditures, larger organizations, and more specialized knowledge. A rush typically begins with the discovery of placer gold made by an individual.