Analysis of the Progressively Enhanced Mine Pressure in the Fully Mechanized Top Coal Caving Work Face of a 20 m Ultra-Thick Coal Seam

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Shi Jiulin ◽  
Yan Shaohong ◽  
Xu Zhuhe ◽  
Xue Jisheng ◽  
Kaikai Zhao ◽  
...  
Keyword(s):  
Reference Value ◽  
Mining Area ◽  
Multilayered Structure ◽  
Pressure Increase ◽  
Structure Evolution ◽  
Mine Pressure ◽  
Thick Coal Seam ◽  
Cantilever Structure ◽  
Lower Structure ◽  
Stage Stage

Considering the large mined area, wide strata moving range, strong mine pressure occurrence, and difficult roof control for the fully mechanized top coal caving in 20 m ultra-thick coal seams, this study analyzes the strata structure evolution and mine pressure occurrence behavior through field test, numerical simulation, and theoretical analysis. Based on the mine condition of the Tashan Coal Mine in the Datong mining area, mechanical models are established for the compound overlying structures. The following can be demonstrated from this study: (1) The hard strata can form three different compound spatial structures at different positions in the overlying rock strata, including the lower combined cantilever structure I, the middle combined cantilever structure II, and the upper hinged structure. (2) Failure of the higher structure can induce compression on the lower structure, which changed the break span of the lower structure. (3) “Simultaneous and nonsimultaneous structural failures” of the compound spatial structure were caused by the variation of the break span of the multilayered structure. (4) Based on the weighting characteristics, there were three stages during work face weighting, including a gradual pressure increase stage (Stage I), an accelerated pressure increase stage (Stage II), and a fast pressure increase stage (Stage III). (5) The mine pressure occurrence demonstrated a “small to medium and to large” feature. (6) Prefracturing techniques should be additionally incorporated to prevent simultaneous failure of the multilayered structure. Findings of the work can demonstrate the emergence of strong mine pressure in the Datong mining area and have theoretical significance and reference value for maintaining safe mining in similar conditions.

scholarly journals Prediction of the First Weighting from the Working Face Roof in a Coal Mine Based on a GA-BP Neural Network

2019 ◽  
Vol 9 (19) ◽  
pp. 4159
Author(s):  
Tan ◽  
Yang ◽  
Chang ◽  
Zhao
Keyword(s):  
Neural Network ◽  
Coal Mine ◽  
Bp Neural Network ◽  
Prediction Models ◽  
Initial Pressure ◽  
Mining Area ◽  
Mine Pressure ◽  
Mine Production ◽  
Production Safety ◽  
Matlab Programming

The accidents caused by roof pressure seriously restrict the improvement of mines and threaten production safety. At present, most coal mine pressure forecasting methods still rely on expert experience and engineering analogies. Artificial neural network prediction technology has been widely used in coal mines. This new approach can predict the surface pressure on the roof, which is of great significance in coal mine production safety. In this paper, the mining pressure mechanism of coal seam roofs is summarized and studied, and 60 sets of initial pressure data from multiple working surfaces in the Datong mining area are collected for gray correlation analysis. Finally, 12 parameters are selected as the input parameters of the model. Suitable back propagation (BP) and GA(genetic algorithm)-BP initial roof pressure prediction models are established for the Datong mining area and trained with MATLAB programming. By comparing the training results, we found that the optimized GA-BP model has a larger determination coefficient, smaller error, and greater stability. The research shows that the prediction method based on the GA-BP neural network model is relatively reliable and has broad engineering application prospects as an auxiliary decision-making tool for coal mine production safety.

Prediction of Top-Coal Caving and Drawing Characteristics Using Artificial Neural Networks in Extremely Thick Coal Seam

2015 ◽  
Vol 743 ◽  
pp. 612-616 ◽  
Author(s):  
J.H. Yu ◽  
De Bing Mao
Keyword(s):  
Neural Networks ◽  
Artificial Neural Networks ◽  
Coal Seam ◽  
Network Model ◽  
Mining Area ◽  
Software Training ◽  
Thick Coal Seam ◽  
Mining Depth ◽  
Training Samples ◽  
Artificial Neural

Based on the feature of large thickness and poor drawing characteristics in extremely thick coal seam top-coal caving method, combined with numerous practical examples analyses, the primarily six factors influence the drawing characteristics were found out which are mining depth, coal seam strength, joint crack development, parting thickness in top-coal, caving ratios, immediate roof filling coefficient. According to 45 typical top-coal caving in extremely thick coal seam samples, the prediction of top-coal caving and drawing characteristics based on artificial neural networks was established and training samples and testing samples was determined. Use SPSS statistical software training the network model. Then select No. 9 coal seam first mining area of Tiaohu mine as the application case. The drawing property was forecast according to the established network model. Application results show that the use of artificial neural networks for top-coal caving and drawing characteristic prediction is effective and feasible.

Development Rule of Full-Mechanized Caving Mining Water-Flowing Fracture Zone in Yanzhou Mining Area

2012 ◽  
Vol 616-618 ◽  
pp. 475-480
Author(s):  
Zhen Li Fan ◽  
Bing Nan Hu
Keyword(s):  
Fracture Zone ◽  
Influence Factors ◽  
Mining Area ◽  
Overburden Rock ◽  
Rock Destruction ◽  
Thick Coal Seam ◽  
Hard Roof ◽  
Mining Depth ◽  
The Face ◽  
Mining Water

The heights of fully-mechanized mining water-flowing fracture zone of Yanzhou mining area were measured by borehole simple hydrology method .In order to confirm the influence degree of the geology and mining factors to the damage height of overburden rock , the paper analyses the measured data by using grey relation analysis theory, and concludes that the face span, mining thickness and mining depth are main influence factors to the height of the water-flowing fracture zone. On this basis, the paper reveals the general rules of fully-mechanized caving mining overburden rock destruction with the on conditions of gentle dip, thick coal seam and hard and medium hard roof by using regression analysis method.

scholarly journals Control of Gob-Side Roadway with Large Mining Height in Inclined Thick Coal Seam: A Case Study

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xie Fuxing
Keyword(s):  
Numerical Simulation ◽  
Coal Pillar ◽  
Simulation Software ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Thick Coal Seam ◽  
Working Face ◽  
Rock Structure ◽  
Large Mining Height ◽  
Mining Height

The gob-side roadway of 130205, a large-mining-height working face in the Yangchangwan coal mine, was investigated in terms of the mine pressure law and support technology for large mining heights and narrow coal pillars for mining roadways. The research included field investigations, theoretical analysis, numerical simulation, field tests, and other methods. This paper analyzes the form of movement for overlying rock structure in a gob-side entry with a large mining height and summarizes the stress state and deformation failure characteristics of the surrounding rock. The failure mechanism of the surrounding rock of the gob-side roadway and controllable engineering factors causing deformation were analyzed. FLAC3D numerical simulation software was used to explore the influence law of coal pillar width, working face mining height, and mining intensity on the stability of the surrounding rock of the gob-side roadway. Ensuring the integrity of the coal pillar, improving the coordination of the system, and using asymmetric support structures as the core support concept are proposed. A reasonably designed support scheme for the gob-side roadway of the working face for 130205 was conducted, and a desirable engineering effect was obtained through field practice verification.

scholarly journals Development and Application of Fluid-Solid Coupling Similar Materials in Discharge Test of Old Goaf Water

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Zhenhua Li ◽  
Mingxiao Ma ◽  
Yongsheng Bao
Keyword(s):  
Silicone Oil ◽  
Control Function ◽  
Similarity Theory ◽  
Water Discharge ◽  
Mining Area ◽  
Similar Material ◽  
Thick Coal Seam ◽  
Evolution Law ◽  
Evolution Characteristics ◽  
Similar Materials

To study the evolution law of the discharge pathway for the old goaf water in the Datong mining area, a new fluid-solid coupling similar material was developed based on the fluid-solid coupling similarity theory. In the developed similar material, sand and barite powder were used as aggregate, polyurethane and white portland cement as binder, and water and silicone oil as regulator. The effects of different proportions on mechanical properties and water physical properties of materials were obtained through the experiments. The results show that the strength of the developed material is mainly controlled by cement and polyurethane, the hydrophilicity is affected by silicone oil, and the permeability coefficient is mainly affected by cement and polyurethane. For grouting agent, cement can realize the overall control function, and polyurethane can realize the local control in a certain range. As an ideal fluid-solid coupling similar simulation material, the developed material can simulate rock mass with different permeability and different strength. Besides, this material has been successfully applied to an experimental study on the mechanism of old goaf water discharge in an extra-thick coal seam in the Datong mining area, and the development and evolution characteristics of the old goaf water discharge pathway is obtained. This new kind of fluid-solid coupling similar material is developed based on the fluid-solid coupling similarity theory, which is suitable for revealing the evolution law of discharge pathway for the old golf water in the Datong mining area.

Research on Surface Deformation with Increasing Mine Depth

2011 ◽  
Vol 243-249 ◽  
pp. 5890-5893
Author(s):  
Gang Chen ◽  
Qiong Wang
Keyword(s):  
Surface Deformation ◽  
Large Range ◽  
Reference Value ◽  
Mining Area ◽  
Deep Mining ◽  
Mining Depth ◽  
Practical Engineering ◽  
Original Rock ◽  
Mine Depth ◽  
The Relationship

After ore mined, the equilibrium state of original rock stress around mining area is damaged, causing surface deforming at large range. With the increasing resource needing and mining intensity, the mines all over the world are gradually in a stage of deep mining, so it is important to study the principle of surface deformation under the condition of deep mining. Finite element method is used to simulate mine process with increasing depth, and the relationship between mining depth and surface deformation is achieved. The result has important reference value to practical engineering.

scholarly journals Pressure-Arching Characteristics in Roof Blocks during Shallow Coal Mining

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yanhai Zhao ◽  
Shuren Wang ◽  
Paul Hagan ◽  
Lianwei Ren ◽  
Zhengsheng Zou
Keyword(s):  
Coal Mining ◽  
Mining Area ◽  
Horizontal Stress ◽  
Linear Distribution ◽  
Arch Models ◽  
Thick Coal Seam ◽  
Roof Structure ◽  
Large Mining Height ◽  
Mining Face ◽  
Nonlinear Distribution

To reveal the performance of the stepped subsidence and the strong roof weighting during shallow coal mining, taking the fully mechanized mining face with large mining height in the Shendong mining area in China as the engineering background, theoretical analysis and numerical simulation were used to analyze the pressure-arching effect of the hanging roof blocks. Three typical pressure-arch models of the roof structure were proposed, such as the symmetrical pressure-arch of two key blocks, the step pressure-arch of multiple key blocks, and the rotative pressure-arch of multiple key blocks. Results indicate that the horizontal stress displays a nonlinear distribution at the abutments of the symmetrical pressure-arch, and there is a linear distribution of horizontal stress with a higher peak value at the midspan of the pressure-arch. The high horizontal stress at the arch abutment is necessary to form the rotative pressure-arch of multiple key blocks. The horizontal stress is relatively less at the arch abutment of the step pressure-arch structure. The main key block is easier to slide in this structure as the boundary horizontal stresses display the nonlinear distribution. The results are of instructive significance for roof weighting forecast and strata control during shallow horizontal mining for a thick coal seam.

scholarly journals A Novel Approach for Predicting the Height of Water-Conducting Fracture Zone under the High Overburden Caving Strength Based on Optimized Processes

Processes ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 950
Author(s):  
Tao Hu ◽  
Gongyu Hou ◽  
Su Bu ◽  
Zhen Zhu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Field Experiment ◽  
Model Simulation ◽  
Coal Mines ◽  
Reference Value ◽  
Time Domain Reflectometry ◽  
Maximum Height ◽  
Protection Measures ◽  
Thick Coal Seam ◽  
Evolution Law

The height of water-conducting fracture zones (WCFZs) is vital for the prevention of water, gas, and roof accidents in coal mines. However, its dynamic evolution law and maximum height are difficult to be obtained by traditional prediction methods, especially for conditions in which there is high overburden caving strength and a thick coal seam. Therefore, taking the 150,313 fully mechanized caving working face in Yingying Coal Mine as a background, according to the principle of optimized processes, a new predicting approach based on the Brillouin optical time-domain reflectometry (BOTDR) is proposed. Firstly, we estimated the height through empirical formula calculation, theoretical analysis, and similar model simulation tests. Secondly, we studied the optimized layout of optical cables in the overburden in detail for predicting the maximum height of the WCFZ and keeping the cables in good performance during field prediction. Thirdly, we researched and optimized the borehole parameters, optical fiber selection, and the special protection measures. Finally, we applied the aforementioned optimized outcomes in the field experiment to dynamically predict the height of the WCFZ. As a result of the field experiment, the distribution characteristics of optical fiber strain, the maximum height, and the evolution law of the WCFZ were obtained through the regular monitoring of fiber strain using BOTDR. The experiment demonstrated that its maximum height is consistent with the results studied indoors. The validation and feasibility of the approach proposed in this paper were verified via the aforementioned studies. The research in this paper has good reference value and important significance for predicting the height of the WCFZ using BOTDR in coal mines with similar geological and productive conditions.

scholarly journals Research on Prevention and mitigation of Deep Mine Hazards in Ningzheng Mining Area

2019 ◽  
Vol 118 ◽  
pp. 04003
Author(s):  
Lan Yu ◽  
Rili Yang ◽  
Chao Zheng ◽  
Shuang Li
Keyword(s):  
Mining Area ◽  
Gansu Province ◽  
Mine Pressure ◽  
Prevention Measures ◽  
Coal Seams ◽  
Deep Mine ◽  
Mining Areas ◽  
Cogeneration System ◽  
Cooling Technology ◽  
Realistic Significance

Ningzheng Mining Area, as one of the key mining areas of Longdong Energy Base in Gansu Province, whose average overburden depth of coal seams is more than 800 meters and average thickness of coal seams ranges from 8m to 14m. This paper analyzed the typical characteristics of water damage, heat damage, high mine pressure and gas disaster in Ningzheng mining area. Disaster prevention measures and two resource utilization prevention technologies (namely EMS cooling technology, Gas power generation and cogeneration system cooling technology) were put forward, the rearch has a realistic significance for the safety exploitation, comprehensive utilization of deep coal resources in China, energy conservation and emission reduction and development of circular economy.

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