Failure characteristics and control technology for large‐section chamber in compound coal seams—A case study in Tashan Coal Mine

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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A case study on control technology of surrounding rock of a large section chamber under a 1200-m deep goaf in Xingdong coal mine, China

Engineering Failure Analysis ◽

10.1016/j.engfailanal.2019.05.039 ◽

2019 ◽

Vol 104 ◽

pp. 112-125 ◽

Cited By ~ 7

Author(s):

Shengrong Xie ◽

Hao Pan ◽

Junchao Zeng ◽

En Wang ◽

Dongdong Chen ◽

...

Keyword(s):

Coal Mine ◽

Surrounding Rock ◽

Control Technology ◽

Large Section

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The inducement of coal spontaneous combustion disaster and control technology in a wide range of coal mine closed area

Environmental Earth Sciences ◽

10.1007/s12665-018-7540-1 ◽

2018 ◽

Vol 77 (10) ◽

Cited By ~ 3

Author(s):

Rongkun Pan ◽

Dong Fu ◽

Zejun Xiao ◽

Lei Chen

Keyword(s):

Coal Mine ◽

Spontaneous Combustion ◽

Control Technology ◽

Coal Spontaneous Combustion ◽

Closed Area ◽

Wide Range ◽

And Control

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Stability of Split-Level Gob-Side Entry in Ultra-Thick Coal Seams: A Case Study at Xiegou Mine

Energies ◽

10.3390/en12040628 ◽

2019 ◽

Vol 12 (4) ◽

pp. 628 ◽

Cited By ~ 4

Author(s):

Junwen Zhang

Keyword(s):

Coal Mine ◽

Coal Pillar ◽

Peak Stress ◽

Coal Seams ◽

Solid Coal ◽

Stress Fluctuation ◽

Pillar Mining ◽

The Stability ◽

Rock Specimens

Split-level longwall gob-side entry (SLGE) has been applied as a special form of small gate pillar mining (or non-coal pillar mining) in thick coal seams. The stability of the coal pillar directly affects the rationality of the layout of the SLGE. Starting from the mining-induced influence around the SLGE, this paper compares the mechanical properties of coal under different mining effects, and studies the rationality of “zero pillar” location against the Xiegou coal mine. The study shows that the key to success of the application of the SLGE is the existence of an intact zone within the triangular coal pillar in spite of double disturbances due to tunneling and coal mining extraction. Laboratory testing shows that the density and uniaxial compressive strength of rock specimens obtained from the triangular coal pillar are smaller than that from the other part of the panel which is concluded to be due to the varied degree of mining-induced influence. The numerical modeling results show that most of the triangular coal pillar is intact after extraction of the panel, and that the peak stress is located in the solid coal beyond the triangular coal pillar. The plastic zone of the triangular coal pillar is only about 1 m after the excavation of the tail gate of the next split-level panel. The physical modeling shows that the tail gate of the next panel is in the destressed zone with only a very small stress fluctuation during the extraction of the next panel. The study shows that the location of the SLGE at Xiegou coal mine is reasonable. SLGE is preferable for ultra-thick coal seams.

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Failure Mechanism and Control Technology of Thick and Soft Coal Fully Mechanized Caving Roadway under Double Gobs in Close Coal Seams

Shock and Vibration ◽

10.1155/2020/8846014 ◽

2020 ◽

Vol 2020 ◽

pp. 1-23

Author(s):

Shengrong Xie ◽

Xiaoyu Wu ◽

Dongdong Chen ◽

Yaohui Sun ◽

En Wang ◽

...

Keyword(s):

Numerical Simulation ◽

Coal Seam ◽

Field Distribution ◽

Control Technology ◽

Coal Seams ◽

Anchor Bolt ◽

Anchor Cable ◽

Coal Pillars ◽

Seam Mining ◽

And Control

The surrounding rock of the roadway under double gobs in the lower coal seams is partially damaged by the mining of the upper coal seam and the stress superimposition of the stepped coal pillars. What is worse, the upper layer of the roof is collapse gangue in double gobs, which makes the anchor cable unable to anchor the reliable bearing layer, so the anchoring performance is weakened. The actual drawing forces of the anchor bolt and anchor cable are only approximately 50 kN and 80 kN, respectively. The roadway develops cracks and large deformations with increasing difficulty in achieving safe ventilation. In view of the above problems, taking the close coal seam mining in the Zhengwen Coal Mine as the engineering background, a theoretical calculation is used to obtain the loading of the step coal pillars and the slip line field distribution of the floor depth. The numerical simulation monitors the stress superimposition of stepped coal pillars and the distribution of elastoplastic areas to effectively evaluate the layout of mining roadways. The numerical simulation also analyzes the effective prestress field distribution of the broken roof and grouting roof anchor cable. A laboratory test was used to monitor the strength of the grouting test block of the broken coal body. Then, we proposed that grouting anchor cable be used to strengthen the weak surface of the roof and block the roof cracks. From on-site measurement, the roadway was seen to be arranged in the lateral stress stabilization area of the stepped coal pillars, the combined support technology of the grouting anchor cable (bolt) + U type steel + a single prop was adopted, the roadway deformation was small, the gas influx was reduced, and the drawing force of the anchor bolt and the anchor cable was increased to approximately 160 kN and 350 kN, respectively. The overall design and control technology of the roadway can meet the site safety and efficient production requirements.

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Prevention and Control Technology Research on Rock Burst of Fully Mechanized Caving Faces and Gob-Side Entry

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.353-356.303 ◽

2013 ◽

Vol 353-356 ◽

pp. 303-306

Author(s):

Zhi Chao Tian ◽

Long Hao Dong ◽

Min Ma ◽

Ye Jiao Liu

Keyword(s):

Rock Burst ◽

Coal Mine ◽

Similar Condition ◽

Economic Benefit ◽

Prevention And Control ◽

Scientific Basis ◽

Surrounding Rock ◽

Control Technology ◽

Technology Research ◽

And Control

According to the actual monitoring data of mining environment and rock burst happening on the 3511 fully-mechanized workface in Anyuan coal mine, the research of the rock burst on the workface and its surrounding rock of gob-side entry is done and the reasonable supporting scheme is determined. The research results are of great guiding importance to the coal mining that has similar condition, provide scientific basis for the control technology of rock burst on the workface and its gob-side entry as well as the reasonable identification of support parameters on the gob-side tunnel, and supply technology protection in order to accelerate the advancing speed of workface. Finally it can produce larger economic benefit.

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