Mode of overlying rock roofing structure in large mining height coal face and analysis of support resistance

2016 ◽  
Vol 23 (12) ◽  
pp. 3262-3272 ◽  
Author(s):  
Feng-feng Wu ◽  
Chang-you Liu ◽  
Jing-xuan Yang
Keyword(s):  
Coal Face ◽  
Large Mining Height ◽  
Support Resistance ◽  
Mining Height

Design of Automatic End-Advanced Hydraulic Support in Coal Face with Deep Dip Angle and Large Mining Height

2010 ◽  
Vol 160-162 ◽  
pp. 1524-1530
Author(s):  
Li Qiang Ma ◽  
Dong Sheng Zhang ◽  
Cheng Guo Zhang ◽  
Xin Qi Cao ◽  
Yong Shen Li
Keyword(s):  
Economic Benefits ◽  
Coal Face ◽  
Hydraulic Support ◽  
Support Costs ◽  
Safety And Reliability ◽  
The Face ◽  
Large Mining Height ◽  
Advanced Support ◽  
Dip Angle ◽  
Mining Height

ZTZL60000/25/45 Automatic End-Advanced Hydraulic Support is developed to meet the needs of the fully mechanized coal face with deep dip angle and large mining height, mechanizing the advanced support of the end and drift, while greatly reducing the construction personnel's labor intensity. Not only the end support strength is enhanced, which improves the safety and reliability of advanced support and generates methods to solve problems related to reserving triangle coal on the face that enhances the support efficiency and reduces support costs, but also more recovered coal resources become available since the height of roadway increases, spawning a certain amount of economic benefits.

scholarly journals Analysis of Fracture Mechanics Theory of the First Fracture Mechanism of Main Roof and Support Resistance with Large Mining Height in a Shallow Coal Seam

2021 ◽  
Vol 13 (4) ◽  
pp. 1678
Author(s):  
Dengfeng Yang
Keyword(s):  
Stress Intensity ◽  
Fracture Mechanics ◽  
Coal Seam ◽  
Main Roof ◽  
In Situ Monitoring ◽  
Control Analysis ◽  
Large Mining Height ◽  
Support Resistance ◽  
Shallow Coal Seam ◽  
Mining Height

Because the first-weighting of a main roof with a large mining height has obvious sudden characteristics and is more severe, which causes large-scale support crushing and has a great impact on the ecological environment of the mining area, it is necessary to conduct an in-depth analysis. This paper studies the mechanical mechanism and asymmetric fracture conditions of a main roof with a large mining height, with the first-weighting occurring in a shallow coal seam. In combination with an asymmetric three-hinged arch structural model, the main roof was regarded as a finite plate model with a crack, and a fracture-mechanics model was established. The conditions and main controlling factors of main roof fracture asymmetry were analyzed, and the determination methods of the first-weighting interval and support resistance were further analyzed. The results show that the stress concentration and the stress-intensity factor increase at the crack tip with the advancement of the face; when the stress-intensity factors increase beyond the critical value, the crack expands until the first-weighting. The sufficient condition for modeling the instability was the length s of the branch crack reaching the protection thickness H of the main roof, and the necessary condition was the activation of the crack. The calculation equations of the first-weighting interval and the support resistance were obtained. The influence weights of each parameter on the support resistance are ordered as follows: overburden load q > rock fracture toughness KC > crack length a > main roof thickness h > weighting interval l. Finally, the theoretical analysis results were verified by an in situ monitoring case of the no. 33,206 working face in the Bulianta coal mine, China. On this basis, a reasonable value of the support resistance is further calculated. The results mentioned above can provide a new method for researching the first-weighting of the main roof and can improve the accuracy of the roof control analysis. The research on the mechanisms of first-weighting and the support resistance can effectively promote the safety production of mine, which is in line with the concept of green and sustainable development of the mine.

Study on rib spalling control of shortwall drilling mining technology with a large mining height

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Yong Yuan ◽  
Cheng Zhu ◽  
Hongmin Wei ◽  
Chaofeng Yuan ◽  
Zhongshun Chen
Keyword(s):  
Mining Technology ◽  
Large Mining Height ◽  
Mining Height

scholarly journals Study on Fracture and Stress Evolution Characteristics of Ultra-Thick Hard Sandstone Roof in the Fully Mechanized Mining Face with Large Mining Height: A Case Study of Xiaojihan Coal Mine in Western China

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Feng Ju ◽  
Meng Xiao ◽  
Zequan He ◽  
Pai Ning ◽  
Peng Huang
Keyword(s):  
High Strength ◽  
Western China ◽  
Stress Evolution ◽  
Working Face ◽  
Mining Condition ◽  
Evolution Characteristics ◽  
Large Mining Height ◽  
Evolution Laws ◽  
Mining Face ◽  
Mining Height

Ultra-thick hard sandstone roofs present high thickness, poor delamination, and wide caving range. The strata pressure of the working face during actual mining increases, having a significant influence on the safe mining of the working face. Especially, in the mining areas of western China, the fully mechanized mining faces with high mining height and high-strength mining are more prominent. Understanding the fractures and stress evolution characteristics of the ultra-thick hard sandstone roof during actual mining is of high significance to control the dynamic pressure on the working face. In this paper, the typical ultra-thick hard sandstone roof of the Xiaojihan coal mine was taken as an example. The structural and chemical composition characteristics were analyzed. Besides, the fracture characteristics of ultra-thick hard roof during the working face mining were analyzed. Moreover, the fracture structure consistency was verified through physical simulation and a field measurement method. Finally, the stress evolution laws in the ultra-thick hard sandstone roof fracture were studied through numerical simulation. The findings demonstrated that (1) the ultra-thick hard sandstone roof was composed of inlaid coarse minerals, which had compact structure, while the Protodyakonov hardness reached up to 3.07; (2) under the high-strength mining condition of fully mechanized mining face with large mining height, the ultra-thick hard sandstone roof had the characteristics of brittle fracture, with a caving span of 12 m; (3) under the high-strength mining condition of fully mechanized mining face with large mining height, the ultra-thick hard sandstone roof followed the stress evolution laws that were more sensitive to the neighboring goaf. Therefore, it was necessary to reduce the fracture span or layering of ultra-thick hard sandstone roof through the manual intervention method adoption or increase either the strength of coal pillar or supporting body, to resist the impact generated during ultra-thick hard sandstone roof fracture.

scholarly journals Determination of Optimal Extrication Location of High Extraction Roadway of Large-Mining-Height Fully Mechanized Face

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Xue-bo Zhang ◽  
Ming Yang
Keyword(s):  
Gas Extraction ◽  
Horizontal Distance ◽  
High Position ◽  
Working Face ◽  
Extraction Site ◽  
Large Mining Height ◽  
Porosity And Permeability ◽  
Permeability Distribution ◽  
Mining Height

Determining the optimal extrication location of the high extraction roadway can improve the gas extrication effect of highly gassy mine and solve the problem of gas concentration overrun at the upper corner, which is of great significance to safety and efficient mine production. According to the actual situation of mine, the gas gushing amount in the goaf, pressure difference at both ends of the working face, the 3D porosity, and permeability distribution of the caving zone and fissure zone were obtained by field measurement and numerical calculation. Through theoretical calculation, the proper extraction site of a high-position alley was determined. On this basis, the optimal extraction site of a high-position alley was determined by numerical analysis of the gas extraction effect at different sites. The results show that as the perpendicular distance between high-position alley and goaf floor increases, the gas extraction amount increases first and then decreases. The concentration of extraction gas gradually increases, and the increasing trend is gradually diminished. With the increase of the horizontal distance between the air return way and the high-position alley, the gas extraction amount and gas extraction concentration increase first and then decrease. The optimal extraction site of a high-position alley should be 39 m vertically away from the goaf floor and 30 m horizontally away from the air return way.

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