An improved model to predict the water-inrush risk from an Ordovician limestone aquifer under coal seams: a case study of the Longgu coal mine in China

2020 ◽  
Vol 35 (3) ◽  
Author(s):  
Huigong Niu ◽  
Jiuchuan Wei ◽  
Huiyong Yin ◽  
Daolei Xie ◽  
Weijie Zhang
Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7287
Author(s):  
Xinxin Zhou ◽  
Zhenhua Ouyang ◽  
Ranran Zhou ◽  
Zhenxing Ji ◽  
Haiyang Yi ◽  
...  

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.


2018 ◽  
Vol 37 (2) ◽  
pp. 288-299 ◽  
Author(s):  
Qiuyu Lu ◽  
Xiaoqin Li ◽  
Wenping Li ◽  
Wei Chen ◽  
Luanfei Li ◽  
...  

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2170 ◽  
Author(s):  
Gangwei Fan ◽  
Shizhong Zhang ◽  
Dongsheng Zhang ◽  
Chengguo Zhang ◽  
Mingwei Chen ◽  
...  

Aquiclude plays a critical role in the occurrence of mining-induced roof water inrush in underground coal mines. This paper proposes an assessment index for the evaluation of aquiclude stability and a threshold value of water inrush from the roof, based on a case study of roof water inrush accidents in Cuimu coal mine, China. The relation between roof water inrush and water level variation in the aquifer, and the characteristics of aquiclude deformation, were studied in this assessment. Using the developed assessment criteria, the likelihood of roof water inrush was categorized into different risk levels, which were followed by a proposal for roof water inrush control measures. The main findings of this study are: a) in Cuimu coal mine, the waterbody in the bed separation between the upper aquifer and the aquiclude directly causes the inrush, and inrush occurs after the water level declines in the aquifer; b) tension-induced horizontal strains of aquiclude can be regarded as the index to evaluate the stability of aquiclude affected by underground coal mining—roof water inrush occurs when the maximum horizontal strain reaches a threshold of 10mm/m—c) based on the critical mining height for aquiclude instability, and the different thicknesses of barrier layers, high-risk zones are identified and inrush controls are proposed.


Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 628 ◽  
Author(s):  
Junwen Zhang

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.


2015 ◽  
Vol 74 (2) ◽  
pp. 1429-1437 ◽  
Author(s):  
Qiang Wu ◽  
Yuanzhang Liu ◽  
Lihong Luo ◽  
Shouqiang Liu ◽  
Wenjie Sun ◽  
...  

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