In coal mining: Origins of longwall mining. The other principal method of modern mining, longwall mining, had been introduced as early as the 17th century and had found general use by the 19th century, but it had long been less productive than room-and-pillar mining

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Longwall mining activities alter the exsisting ground stress field, this changed stress field is known as induced stress. Extraction of coal by longwall mining induces a redistribution of stresses causing the rocks near the mining excavation to accomodate a redistributed load. Effective and efficient longwall mining is dictated by the […]

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LONGWALL RETREAT MINING. The predominant method of longwall mining in Australia is longwall retreat system. In retreat longwall mining, two sets of entries are driven between 100 to 250m apart. When the entries have been driven a predetermined length, say two kilometres, they are connected and a rectangular longwall block is outlined

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Longwall mining is a highly productive underground coal mining technique. Longwall mining machines consist of multiple coal shearers mounted on a series of self-advancing hydraulic ceiling supports. The entire process is mechanized. Longwall mining machines are about 800 feet (240 meters) in width and 5 to 10 feet (1.5 to 3 meters) tall

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A modern longwall is a long term commitment and flexibility is desirable because conditions may change greatly during the life of the equipment (financial conditions may vary and machinery developments may change constraints even if all mining conditions are well known in advance)

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May 24, 2021 This longwall has made history in Chinese mining. It was the first longwall with perpendicular machine sumping and also the first longwall to operate in fully automatic mode, including automatic hoisting of the beam stage loader. This is a special achievement also due to the fact that it was a low thickness seam wall (1.40-1.55 m)

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Longwall top coal caving (LTCC) and large mining height fully mechanized mining are the main ways to recover thick coal seam. However, CSC fires have always affected the safety and efficiency of mining production and lives of coal miners; it is one of the main disasters in coal mines [ 2 ]

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Therefore, for longwall coal mining in similar areas like this, an appropriate advancing speed of coalface is necessary so that the watertable drawdown of shallow aquifer can be controlled within an allowable scope. Based on the strain-permeability function of weakly cemented rocks in Yili No.4 Coal Mine, the response of overburden permeability

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Longwall mining is used in horizontal, tabular deposits (mainly coal), while the others have applications in inclined or vertical, massive deposits, a lmost exclusively metallic or nonmetallic. Because the exploitation openings are intentionally destroyed in the progress of mining, the caving class is truly unique. Rock mechanics principles are

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The concept of longwall mining dates to the late nine-teenth century, but modern, fully mechanized longwall min-ing was not recognized as a viable technique until shield supports were introduced in the mid-1970s [8]. Contempo-rary longwall mining is conducive to high production and subject to strict state and federal safety and health standards

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Jul 26, 2021 The mining methods used in China's coal industry can be classified into three types: longwall mining, gob-side entry retaining, and N00 longwall mining. The longwall mining method, which originated in Britain during the early 18th century, was first used in China in the 1930s and has been developed for approximately 90 years

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Modern underground coal-mining methods can be classified into four distinct categories: room-and-pillar, longwall, shortwall, and thick-seam. Room-and-pillar mining. In this method, a number of parallel entries are driven into the coal seam. The entries are connected at intervals by wider entries, called rooms, that are cut through the seam at

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Feb 12, 2016 1. Longwall machinery The equipment used in longwall mining includes Cutting Machines Armoured Face conveyors (AFC) Powered Face Supports Stage loaders CUTTING MACHINES: • Longwall shearers • Coal plough. 2. Longwall shearers The coal is cut from the coal face by a machine called the shearer (power loader). This machine can weigh 75–120

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longwall mining Mining. a mining method in which very long rectangular blocks of coal are defined during the development stage of the mine and then extracted in a single continuous operation by an automated cutting head moving parallel to the coal face. When the coal is cut, the working area is protected by a movable, powered roof support system

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Sep 14, 2012 The shortest of its 11 longwall faces is now 1,100 ft, with the exception of the company’s Buchanan mine in Virginia, which is running 700 ft due to geological conditions. All of the CONSOL Energy longwall faces are high-voltage state-of-the-art units with electronic controls and controlled start technology (CST) drives

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Cat Longwall Automation. Automation is an integral part of a modern longwall mining operation, allowing the system to work safely and productively around the clock. Ensuring that every piece of equipment is connected and communicating quickly and reliable is critical, and that’s where the Cat PMC family of Programmable Mining Controls comes in

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Longwall Mining Longwall mining is a highly productive underground coal mining technique. Longwall mining machines consist of multiple coal shearers mounted on a series of self-advancing hydraulic ceiling supports

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Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice (typically 1-2 m thick). The longwall panel (the block of coal that is being mined) is typically 3-4 km long and 250-400 m wide. Longwall mining produced 176 million tons of coal in 2007, about 15 percent of total U.S. production

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LONGWALL MINING Overview. In the method of secondary extraction known as longwall mining a relatively long mining face (typically in the range 100 to 300m but may be longer) is created by driving a roadway at right angles between two roadways that form the sides of the longwall block, with one rib of this new roadway forming the longwall face

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Longwall mining is a form of underground coal mining where a long wall of coal is mined in a single slice. The longwall panel is typically 3–4 km long and 250–400 m wide

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Apr 30, 2010 LONGWALL GENERAL LAYOUT TOP Gate FACE Dip direction Bottom Gate - Longwall mining method includes drivage of two long roadways in coal and joining them at the end by a perpendicular drivage forming a face

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