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A placer claim is a mining claim on gravel or ground from which minerals are extracted using water. [1] In the United States, the valuable mineral in a placer claim is almost always gold , although other nations mine placer deposits of platinum , tin , and diamonds .
Placer mining (/ ˈ p l æ s ər /) [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.
When Congress passed the General Mining Act of 1872, the wording was changed to "or other valuable deposits," giving greater scope to the law. The 1872 law was codified as 30 U.S.C. §§ 22-42 [14] The 1872 act also granted extralateral rights to lode claims, and fixed the maximum size of lode claims as 1500 feet (457m) long and 600 feet (183m ...
Placer mining is an important source of gold, and was the main technique used in the early years of many gold rushes, including the California Gold Rush. Types of placer deposits include alluvium, eluvium, beach placers, aeolian placers and paleo-placers. [2] Placer materials must be both dense and resistant to weathering processes. To ...
By 1880, most of the mining had shifted to lode deposits, such as the Empire Mine. Through 1959, the district produced 10.4 million troy ounces (323 tonnes) of lode gold, and 2.2 million troy ounces (68.4 tonnes) of placer gold. [18] The rich placer deposits of the Columbia Basin-Jamestown-Sonora district were found in 1853
Placer mining is a method of extracting gold from alluvial deposits such as sand, gravel, and sediment. [43] [44] These are known as placer deposits which are typically found in riverbeds, stream beds, and floodplains. [45] These deposits typically contain minerals that are resistant to weathering and eroision like gold, platinum, diamonds, and ...
Both types of ore deposit, placer or lode, are mined by both surface and underground methods. [citation needed] Some mining, including much of the rare earth elements and uranium mining, is done by less-common methods, such as in-situ leaching: this technique involves digging neither at the surface nor underground.
Exploration of orogenic gold began after the year 1840 when the source of nearby placer gold deposits was being investigated, after which large scale mining operations began in the 1990s. [45] The Mother Lode Homestake is located in South Dakota, USA, and is a historic mine which was host to orogenic gold held within a banded iron formation ...