Because modern longwalls involve a large number of pieces of equipment (numbers of a magnitude of several hundred items, with many components weighing up to 30 tonnes or more), the process of recovering the equipment from a completed block, transporting it to a new block and then installing it in the new block (often with much of it being taken...
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Longwall mining technology . Longwall coal mining is an extraction process in which large panels of a coal seam up to 7 m thick are completely mined in a series of slices. Fundamental equipment in modern longwall mining are the armoured face conveyor (AFC), powered supports and the shearer (coal cutting machine) (Figure 1).
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Longwall Mining Because extracting more coal is your business' goal. ... Underground coal extraction is a complex and dangerous process, so we test our hydraulic (fluid power) and power transmission components to the highest standards of safety, reliability, and efficiency to ensure your equipment keeps running when you need it most. ...
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Layout Gate roads are driven to the back of each panel before longwall mining begins. The gate road along one side of the block is called the maingate or headgate; the road on the other side is called the tailgate.
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Conventional longwall layout (CLL) for mining coal, trona, etc. is still fraught with problems including low resource recovery, wavy ground surface subsidence, bumps or rockbursts, gateroad ...
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in the longwall highintensity mining of shallow coal seams. Based on continuous medium finite element numerical simulation analysis, the dynamic development of fractures cannot
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The research results can provide important references for the stability of deep underground projects such as coal mining process, tunnel excavation process, nuclear waste storage and other engineering stability. ... Mininginduced strata stress changes, fractures and gas flow dynamics in multiseam longwall mining. International Journal of Rock ...
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When the longwall (LW) face is approaching its finishoff line, the coal mining process generally slows down and then stops to allow the LW equipment to be relocated to a newly prepared installation face following standard procedures, which usually takes approximately 1 ~ 2 months (Kang et al. 2016).During this period, the air is highly likely to penetrate into the active goaf via various ...
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An outline of the longwall mining process is necessary in order to explain these problems in detail. The longwall mining process. A coal seam is typically a contiguous wedge of coal, of varying height, sandwiched between layers of rock. The goal of the coal mining process is to extract as much of this seam as possible (or at least, the high ...
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As is known, the movement of rock strata and ground caused by longwall coal mining is a complicated spatialtemporal process. There are many factors controlling the evolution of movement of caved and fractured zones, such as mining height, mining and roof control methods, rock property and stratigraphic sequence, dip angle, mining sufficiency ...
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Coal mining, extraction of coal deposits from the surface of Earth from underground. Coal has been used since the Bronze Age, 3,000 to 4,000 years ago, and was the basic energy source that fueled the Industrial Revolution of the 18th and 19th centuries. ... The other principal method of modern mining, longwall mining, had been introduced as ...
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Longwall mining is a full ex traction mining process in which large panels of a coal seam up to 5m thick are completely mined. An indicati ve l ongwall panel is 250m
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Context 1 ... mining has become a standard technology for excavating coal from underground mines [4]. This technology, summarized in Figure 1, employs a longwall shearer which is a machine...
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A coal mining car at Lackawanna Coal Mine in Scranton, Pennsylvania Coal miners exiting a winder cage at a mine near Richlands, ia in 1974 Surface coal mining in Wyoming, A coal mine in Frameries, Belgium. Coal mining is the process of extracting coal from the ground or from a mine. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity.
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In the longwall mining method, mine development is carried out in such a manner that large blocks of coal, usually 100 to 300 metres wide and 1,000 to 3,000 metres long, are available for complete extraction (see photograph).A block of coal is extracted in slices, the dimensions of which are fixed by the height of coal extracted, the width of the longwall face, and the thickness of the slice ...
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The selected workstations are typical for longwall mining. Between two or three employees usually work in one site, with the exception of a longwall shearer, a combine harvester assistant and a shift foreman. ... which have an impact on the amount of dust produced during the mining process of the body of coal. The obtained results clearly ...
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Highwall mining is an adaptation of auger mining. Instead of an auger hole, an entry into the coal seam is made by a continuous miner, remotely operated from a cabin at the surface. The cut coal is transported by conveyors behind the miner to the outside. Using a television camera, the operator can see and control the miner's progress.
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longwall method Table of Contents longwall method coal mining Learn about this topic in these articles: underground mining In mining: Longwall mining In the longwall system the ore body is divided into rectangular panels or blocks.
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In the global coal mining industry, a longwall system is recognized as a vital structure for providing protection and safety conditions during the underground mining process.
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Longwall shearer positioning with an inertial navigation system (INS) aided by an odometer is the key technology for automation of the longwall coal mining process.
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Wang et al. (2022) proposed a Gompertz time function model suitable for the longwall coal mining process based on the "three original consistency" modeling idea. Through comparison with the ...
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And the common site of these events are areas of the longwall mining goafs [1], [2]. In China, gassy collieries account for 70% of all stateowned underground mines [3]. In the process of mining these gassy mines, the gas is released into the goaf, and combines with fresh air leaking from the working face to the goaf, forming explosive mixture [4].
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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. ... Although coal mining process continues after that, aquifer watertable gradually recovers on account of recharge from surface ...
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Hence this method is termed the longwall method. In simple words, longwall mining is a method of underground mining, in which coal is extracted from 60m to 200m long faces, moving continuously in one direction over large distances, leaving behind the goaf. The goaf is packed or allowed to cave. Longwall Mining is currently the main method of ...
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Longwall backfill mining effectively mitigates the height of waterconductive fractured zone (HWCFZ), preventing it from reaching the overlying aquifer and thus preserving the groundwater. However, it has the disadvantages of insufficient filling time and space as well as the mutual constraints between filling and mining. A novel continuous extraction and partial backfill (CEPB) water ...
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numerical stress analysis tools for deep coal longwall panels under strong strata. SME preprint 09011. Littleton, CO: Society for Mining, Metallurgy, and Exploration, Inc. Maleki H [1995]. An analysis of violent failure in coal mines: case studies. In: Maleki H, Wopat PF, Repsher RC, Tuchman RJ, eds. Proceedings: Mechanics and Miti
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The longwall machine's mine the coal in horizontal, "panels" that are 800 to 1,500 feet wide and 2 to 3 miles long. In longwall mines as the temporary support protecting the miners is advanced, the roof in the minedout area behind it collapse causing cracks and rock movement that reaches to the land surface hundreds of feet above.
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The natural caving method can be commonly applied to manage goaves in the longwall coal mining approach [1, 2].The accumulation form and mechanical characteristics of the rock mass medium in the goaf directly influence its capacity to support the roof and floor of the cave, thereby affecting the structure of the overlying strata and features of ground subsidence [].
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AFC: improvement of manufacturing process and wear resistance, increasing chain strength and haulage capacity, longer life and reliability. ... The role of ground control in US longwall mining. Since US coal industry was a newcomer in longwall mining in the 1970s and early 1980s, there had been quite a few failures in the startup of longwall ...
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Cun Zhang. Xiaojie Wang. Waterrock interaction is an essential factor in the weakening of coal rock masses. Longterm soaking (LTS) as a type of waterrock interaction is widespread in mining ...
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Coal production from the 36 longwall faces represented % of the 597 million tons of coal produced in the last year. Last year, two longwall mines ceased production and one new mine will start production later this year. The total number of faces dropped from 37 to 36 and the total number of longwall mines declined from 33 to 32.
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Many features in longwall mining, including the caving and compaction of gob strata and the associated stress evolution, are reproduced in the model. ... Coal (mining) ...
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