— Assuming that the top coal above the support F I G U R E 1 Sketch map of the longwall top coal caving mining method is a loose granular medium, Wang et al. proposed a granular flow model for top ...
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— 1. Introduction and background. Longwall top coal caving (LTCC) technique has been widely used to mine thick (> 5 m) to ultra-thick coal seams.In a mechanised LTCC panel, the lower section of the coal seam is cut by a shearer supported by hydraulic shields, while the upper section of the worked seam is allowed to cave by gravity and be …
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— Using longwall top coal caving (LTCC) in an extra-thick seam, many problems appear, such as large broken top coal blocks, frequent arch formation in the drawing process, poor balance of drawing top coal and low top coal recovery, which seriously affect safe, efficient and green mining. In this study, the size distribution of top coal blocks was …
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— Drawing support is one of the unique equipment for longwall top coal caving (LTCC) technology in coal mine, whose structure has a significant effect on the top coal drawing mechanism. This research systemically investigates the effect of the dip angle of shield beam (α), length ratio of shield beam to tail beam (RL), and rotation angle of tail …
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— In case of longwall top, coal caving, the top coal shall fracture, fragment adequately, and cave down onto the rear conveyor immediately after advancing the power supports. ... The second AFC was located in the supporting basement. A rear door is designed in the support system, and the fractured top coal is directed to the rear …
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— Longwall Top Coal Caving was initially developed in the former Soviet Union and France in the 1950s and 1960s. It was then applied in the former Yugoslavia, Hungary, Romania, the former Czechoslovakia and Turkey [4], [5], [6].The 'Soutirage' method which was developed in France in the 1960s is considered as the original form of LTCC [7].The …
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The paper systematically summarized the main achievements of the fully mechanized longwall top-coal caving technology in passed 20 years in China and the conclusion and understanding on the related issues. The paper provided the issues of the theoretical and technical researches to be strengthened in the next step for the fully mechanized …
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— In the process of longwall top coal caving, the selection of the top coal caving interval along the advancing direction of the working face has an important effect on the top coal recovery. To ...
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— The new AFC system marks the 39th delivered to Chinese mines by and its predecessors in the longwall equipment line. The new AFC system is designed for longwall top coal caving (LTCC ...
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— This paper utilizes physical and numerical model experiments to study the deformation and failure mechanisms of goaf-side entries driving adjacent to longwall top coal caving (GEDLTCC) panel. The physical model experiment reveals that the deformation and failure process of GEDLTCC can be divided into four stages: initial deformation …
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— In the support-surrounding rock system of a longwall working face, the main roof strata is generally a thick and hard rock, the soft and weak strata above it can be dealt with as the load by taking main roof strata as a rigid body. ... (2015) Theoretical analysis on the deformation characteristics of coal wall in a longwall top coal caving face ...
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— A 3D particle-based numerical approach to simulate the longwall top coal caving (LTCC) process was proposed, which for the first time the effect of continuous support advance and the face-end support were considered. The shape of drawing body and top coal boundary and the distribution characteristics of coal loss were analysed. …
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— The top-coal caving longwall mining is one of the major mining methods for extracting thick coal seams in China. The top-coal caving mining was estimated to have produced about 0.6 billion metric tons every year, accounts for 18% of underground coal mining in China [3].The major features of the top-coal caving mining are that a …
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— Steep coal seam mining activities will frequently occur during the next few decades in China. In this study, both experimental and numerical methods are employed to investigate the coal drawing from …
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— The longwall top coal caving (LTCC) method is an effective mining approach that originated in Europe, and has been widely and successfully used in China. ... It is covered by the Neogene System with a bottom clay 5.31–23.18 m thick. The bottom clay layer protects the coal mine from water seepage from sand aquifers along the faults in …
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— The roadway formation process of non-pillar coal mining technology in longwall top coal caving panels: (A) the roadway excavation stage, (B) reinforce the support strength of the entry roof and entry rib, (C) split the roof of retained entry, and (D) support the roof and gangue rib of retained entry.
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— The longwall top coal caving (LTCC) production method, applied by forming a face in the horizontal thickness of the seam and also called horizontal section top coal caving, especially in studies originating from China, is widely used in the production of inclined and thick coal seams.In this production method, in addition to the top coal …
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— Dynamic sublevel caving technology (DSCT) proposed by the researchers is one of effective methods to solve the problems of low top coal recovery, poor drawing balance and support stability in longwall top coal caving (LTCC) with large dip angle. To investigate the reasonable number of supports in a sublevel (N) and the top coal …
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supplying special shields for the longwall top coal caving method (LTCC), where extremely thick seams are being mined. This ... to DSK Ibbenbüren Mine in 2013 as part of a full longwall system — including the new GH800B Gleithobel plow ... Mexico and Poland. Since the mid 1990s, plow systems ...
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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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— The changing mining conditions during longwall top coal caving mining (LTCC) were extracted from a coupled numerical model to provide statistically sufficient data for probabilistic analysis. The complex interdependencies among abutment stress, pore pressure, the volume of total gas emission and incremental energy release rate, …
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— Longwall Top Coal Caving (LTCC) is a modified longwall mining method for efficient extraction of the thick coal seams. The major difference between LTCC and the traditional longwall method is the extraction of the caved coal from behind the shields as well as the sheared face (Fig. 1).The method has been widely implemented by the …
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— An extraction method for deep-seated thick seam deposits by underground mining with high resource recovery has remained a great challenge for Indian mining engineers, whereas the longwall top coal caving (LTCC) method has evolved as an effective method for various geo mining conditions in China and other counties. The percentage …
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— Longwall top coal caving (LTCC) mining is the most efficient method for thick and extra-thick coal seam extraction. ... Wang et al. proposed a granular flow model for top-coal caving and a new research system for top-coal drawing. 3, 5, 27, 31 This new research system can take into account the boundary of top coal, draw body, recovery ratio ...
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— The amount of coal for the production panel must be high enough to cover the initial investment of the mechanized longwall system. Longwall top coal caving (LTCC) is a part of longwall mining that is …
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— "Laboratory research on compressive failure mode of top coal in longwall top coal caving face." Chin. J. Rock Mech. Eng. 21 (8): 1178–1182. Google Scholar
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— Panel 42105 of the longwall top coal caving (LTCC) operation is one of the panels in the 4–2 coal seam. It is extracted with the mechanized longwall retreat method. ... In addition, due to a malfunction of the electro-hydraulic monitoring system, it failed to record the shield pressure data in the interval between 266 and 289 m. Thus, in the ...
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— Abstract In this study, the finite difference method (FDM) coupled with a discrete fracture network (DFN) was utilized to analyze longwall top coal caving (LTCC) behaviors. The integrated FDM–DFN model enabled the influence of …
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— In longwall top coal caving (LTCC) mining methods, problems such as large deformations, loss of coal resources, and excavation relay out of balance are often encountered with the …
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— A number of mechanical models of longwall face stability were developed in previous analytical studies. Frith [] proposed a conceptual model that was composed of a vertically cleated coal seam, a horizontally bedded immediate roof loaded by overburden strata, and shield support (Fig. 1).Based on the theory of Euler buckling (in particular, …
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