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Drift Mining
Drift mining is either the mining of an ore deposit by underground methods, or the working of coal seams accessed by adits driven into the surface outcrop of the coal bed. A drift mine is an underground mine in which the entry or access is above water level and generally on the slope of a hill, driven horizontally into the ore seam. Random House dictionary says the origin of the term "drift mine" is an Americanism, circa 1885–1890. Drift is a more general mining term, meaning a near-horizontal passageway in a mine, following the bed (of coal, for instance) or vein of ore. A drift may or may not intersect the ground surface. A drift follows the vein, as distinguished from a crosscut that intersects it, or a level or gallery, which may do either. All horizontal or subhorizontal development openings made in a mine have the generic name of drift. These are simply tunnels made in the rock, with a size and shape depending on their use—for example, haulage, ventilation, or e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tundra
In physical geography, tundra () is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term ''tundra'' comes through Russian (') from the Kildin Sámi word (') meaning "uplands", "treeless mountain tract". There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra. Tundra vegetation is composed of dwarf shrubs, sedges, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. The soil also contains large amounts of biomass and decomposed biomass that has been stored as methane and carbon dioxide in the permafrost, making the tundra soil a carbon sink. As global warming heats the ecosystem and causes soil thawing, the permafrost carbon cycle accelerates and releases much of these soil-containe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slope Mining
Slope mining is a method of accessing valuable geological material, such as coal or ore. A sloping access shaft travels downwards towards desired material. Slope mines differ from shaft and drift mines, which access resources by tunneling straight down or horizontally, respectively. In slope mining, the primary access to the mine is on an incline. Mine hoists may still be used to raise and lower loads on the incline if it is steep, but on shallower slopes, conveyor belts, locomotives or trucks may do the work. Drainage and ventilation of slope mines may be done using the primary slope, or it may be done using auxiliary shafts or bore-holes. See also *2010 Copiapo mining accident 1 (one, unit, unity) is a number representing a single or the only entity. 1 is also a numerical digit and represents a single unit of counting or measurement. For example, a line segment of ''unit length'' is a line segment of length 1. I ... * San Jose Mine References {{Mining-stub U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shaft Mining
Shaft mining or shaft sinking is the action of excavating a mine shaft from the top down, where there is initially no access to the bottom. Shallow shafts, typically sunk for civil engineering projects, differ greatly in execution method from deep shafts, typically sunk for mining projects. Shaft sinking is one of the most difficult of all mine development methods: restricted space, gravity, groundwater and specialized procedures make the task quite formidable. Shafts may be sunk by conventional drill and blast or mechanised means. Historically, mine shaft sinking has been among the most dangerous of all the mining occupations and the preserve of mining contractors called sinkers. Today shaft sinking contractors are concentrated in Canada, Germany, China and South Africa. The modern shaft sinking industry is gradually shifting further towards greater mechanisation. Recent innovations in the form of full-face shaft boring (akin to a vertical tunnel boring machine) have shown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overburden
In mining, overburden (also called waste or spoil) is the material that lies above an area that lends itself to economical exploitation, such as the rock, soil, and ecosystem that lies above a coal seam or ore body. Overburden is distinct from tailings, the material that remains after economically valuable components have been extracted from the generally finely milled ore. Overburden is removed during surface mining, but is typically not contaminated with toxic components. Overburden may also be used to restore an exhausted mining site during reclamation. Interburden is material that lies between two areas of economic interest, such as the material separating coal seams within strata.Peng, Syd S. (1986) ''Coal Mine Ground Control'' (2nd edition), Wiley, New York, page 303, Analogous uses Overburden is also used for all soil and ancillary material above the bedrock horizon in a given area. By analogy, overburden is also used to describe the soil and other material that lies a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oroville, California
Oroville (''Oro'', Spanish for "Gold" and ''Ville'', French for "town") is the county seat of Butte County, California, United States. The population of the city was 15,506 at the 2010 census, up from 13,004 in the 2000 census. Following the 2018 Camp Fire that destroyed much of the town of Paradise, the population of Oroville increased as many people who lost their homes relocated to nearby Oroville. In 2019, the California Department of Finance estimated the population of Oroville is 20,737. Oroville is considered the gateway to Lake Oroville and Feather River recreational areas. The Berry Creek Rancheria of Maidu Indians of California is headquartered in Oroville. Oroville is located adjacent to State Route 70, and is in close proximity to State Route 99, which connects Butte County with Interstate 5. The city of Chico is located about 23 miles (38 kilometers) northwest of the city, and the state capital of Sacramento lies around 70 miles (112 kilometers) to the south ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Feather River
The Feather River is the principal tributary of the Sacramento River, in the Sacramento Valley of Northern California. The river's main stem is about long. Its length to its most distant headwater tributary is just over . The main stem Feather River begins in Lake Oroville, where its four long tributary forks join—the South Fork, Middle Fork, North Fork, and West Branch Feather Rivers. These and other tributaries drain part of the northern Sierra Nevada, and the extreme southern Cascades, as well as a small portion of the Sacramento Valley. The total drainage basin is about , with approximately above Lake Oroville. The Feather River and its forks were a center of gold mining during the 19th century. Since the 1960s, the river has provided water to central and southern California, as the main source of water for the California State Water Project. Its water is also used for hydroelectricity generation. The average annual flow of the Feather River is more than 7 million a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sacramento River
The Sacramento River ( es, Río Sacramento) is the principal river of Northern California in the United States and is the largest river in California. Rising in the Klamath Mountains, the river flows south for before reaching the Sacramento–San Joaquin River Delta and San Francisco Bay. The river drains about in 19 California counties, mostly within the fertile agricultural region bounded by the Coast Ranges and Sierra Nevada known as the Sacramento Valley, but also extending as far as the volcanic plateaus of Northeastern California. Historically, its watershed has reached as far north as south-central Oregon where the now, primarily, endorheic (closed) Goose Lake rarely experiences southerly outflow into the Pit River, the most northerly tributary of the Sacramento. The Sacramento and its wide natural floodplain were once abundant in fish and other aquatic creatures, notably one of the southernmost large runs of chinook salmon in North America. For about 12,000 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lorenzo Sawyer
Lorenzo Sawyer (May 23, 1820 – September 7, 1891) was an American lawyer and judge who was appointed to the Supreme Court of California in 1860 and served as the ninth Chief Justice of California from 1868 to 1870. He served as a United States circuit judge of the United States Circuit Courts for the Ninth Circuit and of the United States Court of Appeals for the Ninth Circuit. He is best known for handing down the verdict in the case of '' Woodruff v. North Bloomfield Gravel Mining Company;'' his verdict is frequently referred to as the "Sawyer Decision." Early years Sawyer was born on a farm in Le Roy, New York the eldest of six children. He worked on the farm during the summer and attended the district school in winter. At the age of fifteen he attended, for a short time, a high school at Watertown, New York, called the Black River Institute, where he became interested in the law. In 1837, having reached the age of seventeen, he went out on his own to pursue a course of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placer Mining
Placer mining () is the mining of stream bed ( alluvial) deposits for minerals. 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. The containing mate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bell Pit
A bell pit is a primitive method of mining coal, iron ore, or other minerals lying near the surface. Operation A shaft is sunk to reach the mineral which is excavated by miners, transported to the surface by a winch, and removed by means of a bucket, much like a well. The bottom of the shaft is enlarged and a sloping roof is created as the desired mineral and surrounding rock is removed – giving its name because the pit in cross section resembles a bell. Typically, no supports were used, and mining continued outwards until the cavity became too dangerous or collapsed at which point another mine was started, often in close proximity. Example and illustrated description This type of mine was in use in prehistoric times, the Middle Ages, and a few continued in use until the early 20th century in the region around Ford, Northumberland. Such pits are common at prehistoric flint working sites such as Grime's Graves in Norfolk and also in the coal mining areas of Yorkshire, the Fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
