Analysis of roof water inrush risk and forecast of the outflow rate of 3229 working face in Tianzhu Coal Mine

The loss of water resources caused by mining fissures is a key factor restricting the green development of coal resources in western mining areas. in order to analyze the influence of mining thickness and face width on the development height of water diversion fracture zone, based on the characteristics of overburden in Xinzhuang Coal Mine, the finite difference software FLAC3D is used to simulate and analyze the size effect of water diversion fracture zone height. The simulation results show that the height of the water diversion fracture zone is positively correlated with the increase of mining thickness and working face width. When the mining thickness is 9m and the width of the working face is 240m, the height of the water diversion fracture zone is 115m, and the average distance between the coal layer 8 of Xinzhuang Coal Mine and the bottom of the Cretaceous aquifer is 106.9m, which may cause water inrush in the mine. Therefore, according to the simulation results and referring to the mining size of part of the mine face in the attached Binchang mining area, it is suggested that the mining thickness of Xinzhuang Coal Mine is about 10m and the width of the working face is not more than 200m.

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An Approach to Dynamic Disaster Prevention in Strong Rock Burst Coal Seam under Multi-Aquifers: A Case Study of Tingnan Coal Mine

Energies ◽

10.3390/en14217287 ◽

2021 ◽

Vol 14 (21) ◽

pp. 7287

Author(s):

Xinxin Zhou ◽

Zhenhua Ouyang ◽

Ranran Zhou ◽

Zhenxing Ji ◽

Haiyang Yi ◽

...

Keyword(s):

Rock Burst ◽

Coal Mine ◽

Water Inrush ◽

Coal Seams ◽

High Position ◽

Integrated Method ◽

Working Face ◽

Strong Rock ◽

And Control

In order to prevent the multi-dynamic disasters induced by rock burst and roof water inrush in strong rock burst coal seams under multi-aquifers, such as is the case with the 207 working face in the Tingnan coal mine considered in this study, the exhibited characteristics of two types of dynamic disasters, namely rock burst and water inrush, were analyzed. Based on the lithology and predicted caving height of the roof, the contradiction between rock burst and water inrush was analyzed. In light of these analyses, an integrated method, roof pre-splitting at a high position and shattering at a low position, was proposed. According to the results of numerical modelling, pre-crack blasting at higher rock layers enables a cantilever roof cave in time, thereby reducing the risk of rock burst, and pre-crack blasting at underlying rock layers helps increase the crushing degree of the rock, which is beneficial for decreasing the caving height of rock layers above goaf, thereby preventing the occurrence of water inrush. Finally, the proposed method was applied in an engineering case, and the effectiveness of this method for prevention and control of multi-dynamics disasters was evaluated by field observations of the caving height of rock layers and micro-seismic monitoring. As a result, the proposed method works well integrally to prevent and control rock burst and water inrush.

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Karst Water Pressure’s Varying Rule and Its Response to Overlying Strata Movement in Coal Mine

Advances in Civil Engineering ◽

10.1155/2020/8848924 ◽

2020 ◽

Vol 2020 ◽

pp. 1-7

Author(s):

Jian Hao ◽

Hua Bian ◽

Anfa Chen ◽

Jiahui Lin ◽

Dongjing Xu

Keyword(s):

Water Level ◽

Water Column ◽

Coal Mine ◽

Simulation Experiment ◽

Water Pressure ◽

Water Inrush ◽

Column Height ◽

Karst Water ◽

Working Face ◽

Water Column Height

Karst water is widespread throughout China and is heavily influenced by complex geological conditions, and floor inrush of karst waters associated with coal seams is the second most common coal mine disaster in China. Due to the limitation of precision and cost of geophysical exploration technology, the volume and pressure of karst water are challenging to measure, especially during the mining process. Therefore, predicting karst pressure’s response to mining is critical for determining the mechanism of water inrush. Here, closed karst water pressure (CKWP) response to mining was studied in an innovative physical simulation experiment. In the simulation experiment, a capsule and a pipe were designed to reflect CKWP and the water level. In the experiment, the vertical stress and karst water level were monitored throughout the process of an advancing coal panel. Monitoring results show that the range of the abutment pressure was about 40 cm, and the peak coefficient value was about 2. When the working face is far away from the water capsule, the stress and water column near the water capsule have no obvious change. With the working face 10 cm from the water capsule, the stress and water column height increased significantly. When the working face was right above the water capsule, the stress and water column rose sharply and reached the maximum value. When the working face advanced beyond the water capsule, the stress and water column height declined. Through establishing a structural mechanics model, the karst water system underneath the working face is assumed to be a hydraulic press. Accordingly, the compressed area was assumed to be a piston. The karst water pressure increases sharply, while the piston is compressed, increasing water inrush risk. This discovery may help determine the water inrush mechanism from a novel point of view.

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The Evolution and Prevention of Water Inrush Due to Fault Activation at Working Face No. II 632 in the Hengyuan Coal Mine

Mine Water and the Environment ◽

10.1007/s10230-018-00579-w ◽

2019 ◽

Vol 38 (1) ◽

pp. 93-103 ◽

Cited By ~ 2

Author(s):

Yang Hu ◽

Jian Sun ◽

Weiqun Liu ◽

Dayong Wei

Keyword(s):

Coal Mine ◽

Water Inrush ◽

Fault Activation ◽

Working Face

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Physical Simulation of the Water-Conducting Fracture Zone of Weak Roofs in Shallow Seam Mining Based on a Self-Designed Hydromechanical Coupling Experiment System

Geofluids ◽

10.1155/2020/2586349 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Hao Zha ◽

Weiqun Liu ◽

Qinghong Liu

Keyword(s):

Surface Water ◽

Coal Mine ◽

Physical Simulation ◽

Early Stage ◽

Water Inrush ◽

Water Environment ◽

Hydromechanical Coupling ◽

Fracture Evolution ◽

Working Face ◽

Seam Mining

Due to inappropriate mining practices, water-conducting fracture zones can develop in an aquifer, not only destroying the surface-water environment but also causing water inrush, even hurting or killing workers. To avoid such disasters, investigating and simulating the evolution mechanism of water-conducting fractures are becoming a research focus in mining engineering, especially regarding the organisation and development of fractures. Our work mainly involved the design of low-strength analogous materials and the simulation of fracture evolution for weak-roof problems in shallow seam mining based on a self-built experimental hydromechanical coupling system. The experimental results show that the vertical stress in the roof increases first as the working face approaches and finally decreases to near its initial value as the working face passes. The relationship between fracture depth and coal-seam excavation distance is obviously nonlinear. The leakage velocity of surface water remains stable in the early stage of excavation and increases when the fracture develops through the main aquifuge. The maximum fracture depth is 76.18 m for the Yili coal mine with weak roofs and shallow coal seams. In addition, we numerically simulated and verified the evolution patterns with the FLAC3D platform. The simulated fracture depth of the Yili coal mine agreed with the in situ borehole observation very well and was more accurate than the output of the empirical formula. Our work provides new methods and relevant data for research on the evolution of water-conducting fractures in weak roofs during shallow seam mining.

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Research on the Height of Water-Flowing Fractured Zone under the Weak Roof Strata and Fully Mechanized Caving Condition

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1092-1093.1448 ◽

2015 ◽

Vol 1092-1093 ◽

pp. 1448-1454

Author(s):

Yan Zhang

Keyword(s):

Coal Mine ◽

Drilling Fluid ◽

Water Inrush ◽

Test Results ◽

Similar Material ◽

Fractured Zone ◽

Working Face ◽

Observation Method ◽

Roof Strata ◽

Similar Material Simulation

The first working face production has suspend because of the great roof water inrush in Mindongyi coal mine, which has weak roof strata and mining use the fully mechanized caving method. In order to detect the height of water-flowing fractured zone, loses of drilling fluid observation method has carried on the flied test, the results showed that while the full-mechanized caving mining thickness is 7.7 m, the height of water-flowing fractured zone is 79.78 m, and the ratio of height to thickness is 10.36, meanwhile, the numerical simulation and similar material simulation have proved the test results are correct. The study enriched the domestic research fruits of the height of water flowing fractured zone, and provided technical references for Mindongyi coal mine mining.

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Similarity simulation study on displacement and stress changes response to coal mining in Longdong coal mine, China

Quarterly Journal of Engineering Geology and Hydrogeology ◽

10.1144/qjegh2020-111 ◽

2020 ◽

pp. qjegh2020-111

Author(s):

Kai Huang ◽

Long Xu ◽

Fusheng Zha ◽

Zhitang Lu ◽

Jiwen Wu ◽

...

Keyword(s):

Coal Seam ◽

Coal Mine ◽

Water Inrush ◽

Coal Pillar ◽

Working Face ◽

Field Investigations ◽

Geological Conditions ◽

Stress Changes ◽

Continuous Mining ◽

The Stability

The complicated geological conditions, including the Fault Sun, in East No. 2 mining sub-area of the Longdong coal mine will influence the stability of strata during mining, leading to serious geological hazards. To circumvent this issue, a similarity simulation experiment was designed and performed in this study, in which the failure characteristics and evolution of displacement and stress within the strata were investigated, and the optimum width of a waterproof coal pillar was determined. The results showed that, as the working face progressed, the coal seam roof gradually deformed, from initial caving of the immediate roof to complete movement and curved subsidence of the entire roof. Significant changes in displacement and stress within the coal seam roof were recorded, and these increased during continuous mining activity. Displacement and stress difference on either side of the fault gradually increased and reached remarkable values with increase in mining distance. On the basis of the experiment results, water inrush is believed to be caused by the interaction between mining and the fault, and, as calculated from parameters collected in field investigations, a waterproof coal pillar of 50 m width should be established to prevent Fault Sun activation, thereby reducing the risk of water inrush from neighbouring aquifers.

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Comprehensive Evaluation and Analysis of Water-Inrush Source in Wolonghu Coal Mine

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1025-1026.926 ◽

2014 ◽

Vol 1025-1026 ◽

pp. 926-929 ◽

Cited By ~ 1

Author(s):

Tao Peng ◽

Hai Chao Zhang ◽

Shu Hao Shen ◽

Zi Qiang Ren

Keyword(s):

Coal Mine ◽

Comprehensive Evaluation ◽

Water Inrush ◽

Water Source ◽

Water Abundance ◽

Sandstone Aquifer ◽

The North ◽

Working Face ◽

Fuzzy Clustering Method ◽

External Sources

Fuzzy clustering method was used in the comprehensive evaluation on the water abundance of sandstone aquifer at the bottom of P2xs (K3) in the Wolonghu Coal Mine. Then this paper contrastively analyzed the characteristics of water-inrush and hydrogeochemistry of adjacent mines. The results show that the water abundance of northern sandstone is rich, the direct water-inrush source of working face is K3 sandstone aquifer, and there is a hydraulic relation between this aquifer and the water of sandstone in adjacent mines. They have the same water source and the north of the coal mine gets a supply from external sources.

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