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Coal mining Coal mining Coal deposits: In geologic terms, coal is a sedimentary rock containing a mixture of constituents, mostly of vegetal origin. Vegetal matter is composed mainly of carbon, hydrogen, oxygen, nitrogen, sulfur, and some inorganic mineral elements. When this material decays under water, in the absence of oxygen, the carbon content increases.
Early coal extraction was smallscale, the coal lying either on the surface, or very close to it. Typical methods for extraction included drift mining and bell well as drift mines, small scale shaft mining was used. This took the form of a bell pit, the extraction working outward from a central shaft, or a technique called room and pillar in which ''rooms'' of coal were extracted with
Shortwall mining method is used only for less than 1% of deep coal production. This method also utilizes a continuous mining machine with moveable roof supports, similar to longwall mining method. Retreat mining method uses pillars or coal ribs to hold up the mine roof. This method is the one of the most dangerous mining method as it is impossible to predict when the ceiling or roof will collapse and crush
longwall mining, where a long wall of coal is mined in a single slice, usually by a large machine. sublevelcaving, where levels of the ore are blasted by explosives; and ; block caving, where large areas of the ore body are blasted and then extracted with the assistance of gravity. We use these three different types of underground mining techniques for coal, diamonds and copper. 3. Underwater mining
o Blast: An older mining method that uses dynamite and explosives to break away the coal seam. Accounts for less than 5% of coal production. o Retreat Mining: One of the most dangerous coal mining methods. Pillars are used to hold up the mine roof as coal is
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 the coal is cut, the working area is protected by a movable, powered roof support system. As the face progresses, the immediate roof
geomechanical processes in coal mining, several improvements have been made in order to increase the production. The basic characteristic of this method is that the area of the coal excavation is extended to the area above by means of a hydraulic shield support. With this method we can make use of the primary and secondary stress conditions and their transformations,
28/10/2020#0183;#32;Coal mining is a term that encompasses the various methods used to extract the carboncontaining rock called coal from the ground. Coal tends to exist in seams, which are lateral layers under the earth that may vary in depth from one or two feet to dozens of feet. Mine types
Methods of underground soft rock mining Longwall mining A set of longwall mining equipment consists of a coal shearer mounted on conveyor operating underneath... Roomandpillar mining or continuous mining Room and pillar mining is commonly done in flat or gently dipping bedded... Blast mining
Coal mining, particularly by underground methods, is traditionally regarded as a dangerous occupation. Although many of the dangers have declined with the advent of safer mine equipment and improved working practices, there are still a number of hazards, primarily of a geological nature, that can impede production, prevent access to coal resources, or even lead to mine disasters with loss of
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