Technique of mining stream bed deposits for minerals
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19th-century miner pouring water into a rocker box which, when rocked back and forth, will help separate gold dust from the alluvium
Placer mining (/ˈplæsər/)[1] is the mining of stream bed (alluvial) deposits for minerals.[2] This may be done by open-pit (also called open-cast 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—deposits of sand and gravel in modern or ancient stream beds, or occasionally glacial deposits. The metal or gemstones, having been moved by stream flow from an original source such as a vein, are typically only a minuscule portion of the total deposit. Since gems and heavy metals like gold are considerably denser than sand, they tend to accumulate at the base of placer deposits.
Placer deposits can be as young as a few years old, such as the Canadian Queen Charlotte beach gold placer deposits, or billions of years old like the Elliot Lake uranium paleoplacer within the Huronian Supergroup in Canada.[3]
The containing material in an alluvial placer mine may be too loose to safely mine by tunnelling, though it is possible where the ground is permanently frozen. Where water under pressure is available, it may be used to mine, move, and separate the precious material from the deposit, a method known as hydraulic mining, hydraulic sluicing or hydraulicking.
^"Placer mining (US)". American English Dictionary. Retrieved January 9, 2015.
Placermining (/ˈplæsər/) is the mining of stream bed (alluvial) deposits for minerals. This may be done by open-pit (also called open-cast mining) or...
sedimentary processes. The name is from the Spanish word placer, meaning "alluvial sand". Placermining is an important source of gold, and was the main technique...
Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment. In the placermining of gold or...
explorers discovered placer gold in the Kenai River in 1848, but no gold was produced. Gold mining started in 1870 from placers southeast of Juneau, Alaska...
placers. Other placer deposits on the west bank of the Colorado River were quickly found, including the Picacho and Cargo Muchacho districts. Placer gold...
Recreational mining is often small-scale placermining but has been challenged for environmental reasons. The disruption of old gold placer deposits risks...
Recreational mining is often small-scale placermining but has been challenged for environmental reasons. The disruption of old gold placer deposits risks...
Diamonds were reported from numerous places across India, but most of the diamond mining took place by placermining in the drainages of the Pannar River...
mountains, they used placermining to extract gold from the local waterways. Placer mines began to appear all over Park County after 1861. Placer gold was found...
land after the mine is closed. Mining materials are often obtained from ore bodies, lodes, veins, seams, reefs, or placer deposits. The exploitation of...
panning, or simply panning, is a form of placermining and traditional mining that extracts gold from a placer deposit using a pan. The process is one...
ore and other materials in the process of mining. Pans are used for placermining operations, such as gold panning. The traditional method of cracking...
strip mining is done on softer minerals such as clays and phosphate removed. Smoother coal seams can also be extracted this way. With placermining, dredge...
Look up placer in Wiktionary, the free dictionary. Placer may refer to one of the following: Placer deposit Placer sheep PlacerminingPlacer (geography)...
extended similar rules to placermining claims in the "placer law" signed into law on July 9, 1870. The Chaffee law of 1869 and the placer law of 1871 were combined...
the recovery of black sands, gold, and other minerals from placer deposits during placermining operations. They may be small-scale, as used in prospecting...
Colorado gold placermining town located about a mile east of Leadville in California Gulch, was the location to one of the richest placer gold strikes...
used by miners and prospectors to indicate the presence of a placer formation. Placermining activities produce a concentrate that is composed mostly of...
population and Placer Dome, and also later Barrick Gold, once they bought Placer Dome. In August 2005 Placer Dome had interests in 16 mining operations in...
National Register Snow Creek Placer Claim No. 1, which is separately listed on the National Register Erik Lindblom Placer Claim, which is separately listed...
Castleman), etc. Drift mining methods were used extensively to mine placer deposits during the early years (1899- ) of the Nome mining district. During summer...
form of placermining. However, panning cannot take place on a large scale, and industrious miners and groups of miners graduated to placermining "cradles"...
placer gold discovery, achieved fame as a silver-mining district, then relied on lead and zinc in its later days. Butte, Montana began miningplacer gold...
River Canyon in Colorado. The Montrose PlacerMining Company built the flume in the 1880s to facilitate gold mining. Some sections of the flume remain attached...
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