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Retreat Mining
Retreat mining is the removal of pillars in the underground mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ... technique known as room and pillar mining. In the first phase of room and pillar mining, tunnels are advanced into the coal or ore body in a rectangular pattern resembling city streets. Pillars are left between tunnels to support the weight of the overburden. The first phase is known as "mining on the advance," from the entrance toward the further reaches of the reserve. In the second phase, once advance mining has been completed, pillars are removed "on the retreat." Removing or "pulling" pillars begins far from the entrance and proceeds toward the entrance. As the pillars are removed, the mine collapses because nothing remains to support the roof and overb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barrier Panel
A barrier or barricade is a physical structure which blocks or impedes something. Barrier may also refer to: Places * Barrier, Kentucky, a community in the United States * Barrier, Voerendaal, a place in the municipality of Voerendaal, Netherlands * Barrier Bay, an open bay in Antarctica * Barrier Canyon, the former name of Horseshoe Canyon (Utah) * Barrier Lake, Alberta, Canada * Barrier Mountain, the former name of Mount Baldy (Alberta) * Barrier Ranges, a mountain range in New South Wales, Australia * Division of Barrier, a former Australian Electoral Division in New South Wales * The Barrier, a common synonym for the city of Broken Hill, New South Wales :*''The Barrier Miner'', the city's newspaper :* Barrier Highway, in Australia, from SA to NSW via Broken Hill * The Barrier, a lava dam in British Columbia, Canada * The Barrier (Kenya), an active shield volcano in Kenya * The Barrier, an early name for the Ross Ice Shelf, Antarctica In arts and entertainment Film * '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasibly created Chemical synthesis, artificially in a laboratory or factory. Ores recovered by mining include Metal#Extraction, metals, coal, oil shale, gemstones, limestone, chalk mining, chalk, dimension stone, rock salt, potash, gravel, and clay. The ore must be a rock or mineral that contains valuable constituent, can be extracted or mined and sold for profit. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even fossil water, water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, and final mine reclamation, reclamation or restoration of the land after the mine is closed. Mining ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Room And Pillar
Room and pillar or pillar and stall is a variant of breast stoping. It is a mining system in which the mined material is extracted across a horizontal plane, creating horizontal arrays of rooms and pillars. To do this, "rooms" of ore are dug out while "pillars" of untouched material are left to support the roof – overburden. Calculating the size, shape, and position of pillars is a complicated procedure, and an area of active research. The technique is usually used for relatively flat-lying deposits, such as those that follow a particular stratum. Room and pillar mining can be advantageous because it reduces the risk of surface subsidence compared to other underground mining techniques. It is also advantageous because it can be mechanized, and is relatively simple. However, because significant portions of ore may have to be left behind, recovery and profits can be low. Room and pillar mining was one of the earliest methods used, although with significantly more manpower. The room ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mine Safety And Health Administration
The Mine Safety and Health Administration (MSHA) () is a small agency of the United States Department of Labor which administers the provisions of the Federal Mine Safety and Health Act of 1977 (Mine Act) to enforce compliance with mandatory safety and health standards as a means to eliminate fatal accidents, to reduce the frequency and severity of nonfatal accidents, to minimize health hazards, and to promote improved safety and health conditions in the nation's mines. MSHA carries out the mandates of the Mine Act at all mining and mineral processing operations in the United States, regardless of size, number of employees, commodity mined, or method of extraction. David Zatezalo was sworn in as Assistant Secretary of Labor for Mine Safety and Health, and head of MSHA, on November 30, 2017. He served until January 20, 2021. Jeannette Galanais served as Acting Assistant Secretary by President Joe Biden on February 1, 2021 until Christopher Williamson took office on April 11, 20 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crandall Canyon Mine
The Crandall Canyon Mine, formerly Genwal Mine, was a bituminous underground coal mine in northwestern Emery County, Utah, United States. The mine made headline news when six miners were trapped by a collapse in August 2007. Ten days later, three rescue workers were killed by a subsequent collapse. The six miners were later declared dead and their bodies were never recovered. Location and geography The Crandall Canyon Mine is located at (39.460000°, -111.167639°) with its entrance at an elevation of . The mine is located in Emery County, Utah, in the Wasatch plateau coal field. The mine is located about south of Salt Lake City, southeast of Fairview, and about west north-west of Huntington. The mine is located in Crandall Canyon about west of its junction with the main highway road, State Route 31, which runs through Huntington Canyon. The Manti-La Sal National Forest surrounds the mine. The mine conducts surface operations on 10 acres (40,000 m2) of disturbed land ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Washington Post
''The Washington Post'', locally known as ''The'' ''Post'' and, informally, ''WaPo'' or ''WP'', is an American daily newspaper published in Washington, D.C., the national capital. It is the most widely circulated newspaper in the Washington metropolitan area and has a national audience. As of 2023, the ''Post'' had 130,000 print subscribers and 2.5 million digital subscribers, both of which were the List of newspapers in the United States, third-largest among U.S. newspapers after ''The New York Times'' and ''The Wall Street Journal''. The ''Post'' was founded in 1877. In its early years, it went through several owners and struggled both financially and editorially. In 1933, financier Eugene Meyer (financier), Eugene Meyer purchased it out of bankruptcy and revived its health and reputation; this work was continued by his successors Katharine Graham, Katharine and Phil Graham, Meyer's daughter and son-in-law, respectively, who bought out several rival publications. The ''Post ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Associated Press
The Associated Press (AP) is an American not-for-profit organization, not-for-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association, and produces news reports that are distributed to its members, major U.S. daily newspapers and radio and television broadcasters. Since the award was established in 1917, the AP has earned 59 Pulitzer Prizes, including 36 for photography. The AP is also known for its widely used ''AP Stylebook'', its AP polls tracking National Collegiate Athletic Association, NCAA sports, sponsoring the National Football League's annual awards, and its election polls and results during Elections in the United States, US elections. By 2016, news collected by the AP was published and republished by more than 1,300 newspapers and broadcasters. The AP operates 235 news bureaus in 94 countries, and publishes in English, Spanish, and Arabic. It also operates the AP Radio Network, which provides twice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longwall Mining
Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically thick). The section of rock that is being mined, known as the longwall panel, is typically long, but can be up to long and wide. The longwall method compares with shortwall, room-and-pillar, and several others. History The basic idea of longwall mining was developed in England in the late 17th century, although it may have been anticipated in the pre-industrial era by a similar technique utilized by the Hopi of Northeastern Arizona in the 14th century. Miners undercut the coal along the width of the coal face, removing coal as it fell, and used wooden props to control the fall of the roof behind the face. This was known as the Shropshire method of mining. While the technology has changed considerably, the basic idea remains the same, to remove essentially all of the coal from a broad coal face and allow the roof and overlying rock to collapse into the void be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountaintop Removal Mining
Mountaintop removal mining (MTR), also known as mountaintop mining (MTM), is a form of surface mining at the summit or summit ridge of a mountain. Coal seams are extracted from a mountain by removing the land, or overburden, above the seams. This process is considered to be safer compared to underground mining because the coal seams are accessed from above instead of underground. In the United States, this method of coal mining is conducted in the Appalachian Mountains in the eastern United States. Explosives are used to remove up to 400 vertical feet (120 m) of mountain to expose underlying coal seams. Excess rock and soil is dumped into nearby valleys, in what are called "holler fills" ("hollow fills") or "valley fills". Overview Mountaintop removal mining (MTR), also known as mountaintop mining (MTM), is a form of surface mining that involves the topographical alteration and/or removal of a summit, hill, or ridge to access buried coal seams. The MTR process involves the remo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Fracturing
Fracking (also known as hydraulic fracturing, fracing, hydrofracturing, or hydrofracking) is a well stimulation technique involving the fracturing of Formation (geology), formations in bedrock by a pressurized liquid. The process involves the high-pressure injection of "fracking fluid" (primarily water, containing sand or other hydraulic fracturing proppants, proppants suspended with the aid of thickening agents) into a wellbore to create cracks in the deep-rock formations through which natural gas, petroleum, and brine will flow more freely. When the hydraulic pressure is removed from the well, small grains of hydraulic fracturing proppants (either sand or aluminium oxide) hold the fractures open. Fracking, using either hydraulic pressure or acid, is the most common method for well stimulation. Well stimulation techniques help create pathways for oil, gas or water to flow more easily, ultimately increasing the overall production of the well. Both methods of fracking are classe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
