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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.
Placer mining, ancient method of using water to excavate, transport, concentrate, and recover heavy minerals from alluvial or placer deposits. Examples of deposits mined by means of this technique are the gold-bearing sands and gravel that settle out from rapidly moving streams and rivers at points.
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.
10 paź 2024 · Mining - Placer, Streams, Alluvial: Placers are unconsolidated deposits of detrital material containing valuable minerals. The natural processes by which they form range from chemical weathering to stream, marine, and wind action.
14 kwi 2015 · Unlike hardrock mining, which extracts veins of precious minerals from solid rock, placer mining is the practice of separating heavily eroded minerals like gold from sand or gravel. The word placer is thought to have come from Catalan and Spanish, meaning a shoal or sand bar.
Placer mining is the by far most common mining activity practiced by hobby prospectors, as the gold doesn’t need to be extracted from hard rock. Another reason is that placers often lie on the surface, and are accessible to nearly anyone using just hand tools.
Placer deposit, natural concentration of heavy minerals caused by the effect of gravity on moving particles. When heavy, stable minerals are freed from their matrix by weathering processes, they are slowly washed downslope into streams that quickly winnow the lighter matrix.
