scholarly journals Movement Law and Discriminant Method of Key Strata Breakage Based on Microseismic Monitoring

2019 ◽  
Vol 2019 ◽  
pp. 1-19 ◽  
Author(s):  
Yang Li ◽  
Tianhong Yang ◽  
Weidong Song ◽  
Ling Yu
Keyword(s):  
High Intensity ◽  
Microseismic Monitoring ◽  
Geological Structure ◽  
Western China ◽  
Dynamic Monitoring ◽  
Ecological Environment ◽  
Environmental Damage ◽  
Key Strata ◽  
Key Stratum ◽  
Working Face

Because of the unique natural geography, geological structure, and ecological environment, there are serious geological disasters and environmental damage caused by the high-intensity mining in Western China. It seriously restricts the development of coal resources and the protection of ecological environment. In order to fully capture the law of key stratum breakage with high-intensity mining, the IMS microseismic system was introduced into Xiaojihan coal mine which is a typical high-intensity mining mine in Western China, and the whole process dynamic monitoring was carried out. The process of key stratum breakage was analysed by MS data, which were in agreement with the pressure analysis results of the hydraulic support of the working face. The results showed that there were the obvious forewarning characteristics in microseismic event number, energy release, energy index, Schmidt number, coefficient of seismic response, and b value when the key stratum was breaking. Then, a method to discriminate the breakage of key stratum was proposed by using the forewarning characteristics, which could provide the guidance for prevention and control of geological hazards in the working face with high-intensity mining.

scholarly journals Deformation Rules for Surrounding Rock in Directional Weakening of End Roofs of Thin Bedrocks and Ultrathick Seams

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Fei Liu ◽  
Zhanguo Ma ◽  
Yongsheng Han ◽  
Zhimin Huang
Keyword(s):  
Abutment Pressure ◽  
Main Roof ◽  
Stability Control ◽  
Surrounding Rock ◽  
Western China ◽  
Resource Exploitation ◽  
Failure Characteristics ◽  
Key Strata ◽  
Working Face ◽  
Geological Conditions

With the deployment of China’s energy strategy in the western regions, complex geological mining conditions such as thin bedrock and ultrathick seams in western China have caused a series of problems such as serious deformation of the surrounding rock at the ends of the working face and the increase in the lead abutment pressure of the roadways; the research on end roof deformation in the resource exploitation in western China has become one of the great demands of the industry. Based on the failure characteristics of rock mass, relying on the actual mining geological conditions of a coal mine in Inner Mongolia, the failure characteristics of the overlying rock strata under the influence of mining were simulated and analyzed using similar material simulation experiment, which intuitively reproduced the failure and deformation processes of the immediate roof, main roof, and key strata and revealed the mechanical mechanism of the directional weakening of the end roof. It is of great significance for the stability control of the surrounding rock at the end of the fully mechanized caving face in the thin bedrocks and ultrathick seams, reducing the abutment pressure of gate roadway and controlling the spontaneous combustion of residual coal in the goaf.

scholarly journals Research on Surface Failure Law of Working Faces in Large Mining Height and Shallow Buried Coal Seam

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Zhenhua Li ◽  
Yingkun Pang ◽  
Yongsheng Bao ◽  
Zhanyuan Ma
Keyword(s):  
Near Field ◽  
Mining Area ◽  
Surface Cracks ◽  
Large Space ◽  
Key Strata ◽  
Key Stratum ◽  
Surface Failure ◽  
Working Face ◽  
Large Mining Height ◽  
Mining Height

In the process of high-intensity and large-space mining in Shendong mining area, various surface cracks are generated on the surface, resulting in serious damage to the surface buildings and the local ecological environment. To study the influence of overlying rock movement on surface failure of near-field single key strata of near-shallow buried and large mining height working face, the relationship between overburden movement, strata pressure appearance, and surface failure at working face 52307 in Daliuta mining area was analyzed by field measurement and numerical simulation. The results show the following: (1) there is only one thick and hard key stratum in the overburden of large mining height and near-shallow buried working face. Under the condition of presplitting roof blasting, the first weighting step is still as high as 95 m, and the periodic breaking step of roof is 20–30 m. During the weighting, the working resistance of support is still close to the rated resistance. (2) The single key stratum plays an obvious role in controlling overburden movement. After the first weighting of the working face, a stepped subsidence crack appears on the surface within a short time, and the crack lags behind the working face for about 5 m. (3) During each periodic weighting process, the breaking and subsidence of key blocks are accompanied by surface cracks.

scholarly journals Effect of mining rate on the working face with high-intensity mining based on microseismic monitoring: a case study

2017 ◽  
Vol 14 (2) ◽  
pp. 350-358 ◽  
Author(s):  
Yang Li ◽  
Tian-hong Yang ◽  
Hong-lei Liu ◽  
Xian-gang Hou ◽  
Hong Wang
Keyword(s):  
High Intensity ◽  
Microseismic Monitoring ◽  
Working Face

scholarly journals Mechanism and Evolution Control of Wide Coal Pillar Bursts in Multithick Key Strata

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Wenhao Guo ◽  
Anye Cao ◽  
Chengchun Xue ◽  
Yang Hu ◽  
Songwei Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Stress Concentration ◽  
Theoretical Analysis ◽  
Coal Mine ◽  
Coal Pillar ◽  
Western China ◽  
Key Strata ◽  
Working Face ◽  
Microseismic Events ◽  
Evolution Control

Coal mine pillar burst frequently occurs in Western China, which seriously restricts safe production. This paper takes the 35 m coal pillar of the 3102 working face of MKQ coal mine as the engineering background. The mechanism and evolution control of pillar bursts in multithick key strata are studied using field investigation, theoretical analysis, and numerical simulation. The mechanism of dynamic and static stress-induced pillar bursts was revealed combining the “O-X” broken features for key strata and numerical simulation of pillar stress evolution. A prevention scheme is put forward for strata presplit blasting and adjusting coal pillar width to minimize the dynamic and static stresses. The results demonstrate the following. (1) In the multithick strata, the first and second near-field subkey strata have perpendicular “O-X” broken features, whereas the third far-field subkey has parallel “O-X” broken features. The working face has three kinds of periodic weighting phenomena: long, medium, and short. (2) The simulated vertical stress curve of 35 m coal pillar goes through three states: two-peak, asymmetric trapezoidal and symmetrical trapezoidal shape with the different advancing position of working face. The stress concentration is extensively promoting a high-risk area for rock burst. (3) The coal pillar burst was induced by the superposition of energy released by the key strata breaking and the elastic energy accumulated in the wide coal pillar. (4) The monitoring data showed that the long, medium, and short periodic weighting steps of multithick key strata are 141.6 m, 43.2–49.6 m, and 17.6–27.2 m, respectively. The microseismic events energy, frequency, and stress of hydraulic support increment are the highest during the long periodic weighting, and the spatial distribution of microseismic events coincides with the stress concentration area. The theoretical analysis is confirmed with the field practice.

scholarly journals Roof structure of shallow coal seam group mining in Western China

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255047
Author(s):  
Jian Cao ◽  
Qingxiang Huang
Keyword(s):  
Coal Seam ◽  
Western China ◽  
Beam Structure ◽  
Key Strata ◽  
Key Stratum ◽  
Roof Structure ◽  
Support Resistance ◽  
Shallow Coal Seam ◽  
Mining Height

In order to realize roof control of shallow coal seam group mining in Western China, combining with engineering statistics, physical simulation and theoretical analysis, the roof weighting characteristics during lower coal seam mining were revealed, and the classification of shallow coal seam group was proposed. Based on this, mechanical models of roof structure were set up, and the calculation method of support resistance was determined. The results show that the roof weighting is closely related to the interburden thickness and the mining height of lower coal seam, considering the ratio of interburden thickness to the mining height, as well as the key stratum structure, the classification of shallow coal seam group was put forward. The first type is shallow coal seam group with no key stratum (SCSG-No), its roof pressure is mainly affected by caving roof of upper coal seam, and the interburden roof forms slanting pillar-beam structure. The second type is shallow coal seam group with single key stratum (SCSG-S), interburden roof represents step voussoir beam structure. The third type is shallow coal seam group with double key strata (SCSG-D), interburden roof can form double key strata structure, the lower key stratum forms slanting step voussoir beam structure, while the upper key stratum forms voussoir beam structure, besides, longwall face represents large—small periodic weighting. Through establishing the roof structure models, the calculation formulas of support resistance were determined, it can provide basis for roof control and promote safe mining in Western China.

Real-time microseismic monitoring and its characteristic analysis in working face with high-intensity mining

2016 ◽  
Vol 132 ◽  
pp. 152-163 ◽  
Author(s):  
Yang Li ◽  
Tian-Hong Yang ◽  
Hong-Lei Liu ◽  
Hong Wang ◽  
Xian-Gang Hou ◽  
...  
Keyword(s):  
Real Time ◽  
High Intensity ◽  
Microseismic Monitoring ◽  
Characteristic Analysis ◽  
Working Face

scholarly journals EVALUATION OF ECOLOGICAL ENVIRONMENT SECURITY IN CONTIGUOUS POVERTY ALLEVIATION AREA OF SICHUAN PROVINCE

2018 ◽  
Vol XLII-3 ◽  
pp. 1935-1939
Author(s):  
W. Xian ◽  
Y. Chen ◽  
J. Chen ◽  
X. Luo ◽  
H. Shao
Keyword(s):  
Poverty Alleviation ◽  
Research Area ◽  
Sichuan Province ◽  
Assessment Model ◽  
Dynamic Monitoring ◽  
Practical Significance ◽  
Ecological Environment ◽  
Environmental Damage ◽  
Ecological Security ◽  
The Impact

According to the overall requirements of ecological construction and environmental protection, rely on the national key ecological engineering, strengthen ecological environmental restoration and protection, improve forest cover, control soil erosion, construct important ecological security barrier in poor areas, inhibit poverty alleviation through ecological security in this area from environmental damage to the vicious cycle of poverty. Obviously, the dynamic monitoring of ecological security in contiguous destitute areas of Sichuan province has a policy sense of urgency and practical significance. This paper adopts RS technology and GIS technology to select the Luhe region of Jinchuan county and Ganzi prefecture as the research area, combined with the characteristics of ecological environment in poor areas, the impact factors of ecological environment are determined as land use type, terrain slope, vegetation cover, surface water, soil moisture and other factors. Using the ecological environmental safety assessment model, the ecological environment safety index is calculated. According to the index, the ecological environment safety of the research area is divided into four levels. The ecological environment safety classification map of 1990 in 2009 is obtained. It can be seen that with the human modern life and improve their economic level, the surrounding environment will be destroyed, because the research area ecological environment is now in good, the ecological environment generally tends to be stable. We should keep its ecological security good and improve local economic income. The relationship between ecological environmental security and economic coordinated development in poor areas has very important strategic significance.

Prediction of rockbursts in a typical island working face of a coal mine through microseismic monitoring technology

2021 ◽  
Vol 113 ◽  
pp. 103972
Author(s):  
Chao Zhang ◽  
Gaohan Jin ◽  
Chao Liu ◽  
Shugang Li ◽  
Junhua Xue ◽  
...  
Keyword(s):  
Coal Mine ◽  
Microseismic Monitoring ◽  
Monitoring Technology ◽  
Working Face

Problems of Ecological Environment in Western China

2004 ◽  
Vol 37 (3) ◽  
pp. 15-20 ◽  
Author(s):  
ZHANG WENJUAN ◽  
GAO JIXI
Keyword(s):  
Western China ◽  
Ecological Environment

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.

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