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The name is from the Spanish word placer, meaning "alluvial sand". 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 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 ...
For example; the medium-sized Coburn mineral sands deposit, Western Australia, is 230 million tonnes at 1.1% heavy minerals, and is 13 km long. The Tormin mine, on the Western Cape of South Africa's coastline, provides a unique ocean beach feature, which exposes the resource to wave and tidal conditions that result in a natural jigging effect.
This method involved digging a shaft 6 to 13 meters (20 to 43 ft) deep into placer deposits along a stream. Tunnels were then dug in all directions to reach the richest veins of pay dirt. In the most complex placer mining, groups of prospectors would divert the water from an entire river into a sluice alongside the river, and then dig for gold ...
Hanakotoba, also known as 花言葉 – Japanese form of the language of flowers; List of national flowers – flowers that represent specific geographic areas; Plants in culture – uses of plants by humans; Narcissus in culture – uses of narcissus flowers by humans
This is a list of plants organized by their common names. However, the common names of plants often vary from region to region, which is why most plant encyclopedias refer to plants using their scientific names , in other words using binomials or "Latin" names.
The word placer derives from the Spanish placer, meaning shoal or alluvial/sand deposit, from plassa (place) from Medieval Latin placea (place) the origin word for "place" and "plaza" in English. The word in Spanish is thus derived from placea and refers directly to an alluvial or glacial deposit of sand or gravel.
[5] [6] Several invasive plant species such as wild garlic mustard, kudzu, and multiflora rose can also cause harm by out-competing and displacing native species from the park. [7] Feral hogs are another major invasive threat to the park, as they are habitat generalists that will eat just about anything, including the roots and foliage of the ...