The channel and characteristics of the stope supplied by atmospheric precipitation in the karst landform mining area

Abstract Atmospheric precipitation causes some mining faces, mining areas or mines to be flooded every year. In order to explore the relationship between atmospheric precipitation and mine water inflow under Karst geomorphic conditions in Guizhou Province, some typical mine related data were collected systematically. It was found that atmospheric precipitation can supply mine goaf through weathered zone cracks, mining fissures, water conducting faults, water flowing subsided columns and karst channels. These channels are in the form of surface infiltration, pipeline flow and layered recharge Replenish the goaf. The results show that the mine water inflow is significantly affected by rainfall under all kinds of recharge modes, the correlation between them is significant under layered recharge mode，the correlation coefficient R reaches 0.88. The recharge channel is filled by loess and other materials on the surface, and has the self-healing characteristics of gradual plugging; the recharge amount is affected by the burial depth of coal seam and the rock combination characteristics of the upper roof. The deeper the coal seam is, the worse the recharge effect is to the mine. The results show that the atmospheric precipitation is the main water filling source of coal mine stope water inflow in the study area, and its recharge has seasonal characteristics. The mine water inflow in rainy season is 1.2-12 times of that in dry season, with an average of 1.9 times; the recharge of mine water by atmospheric precipitation has hysteresis, the lag time of surface infiltration recharge mine is generally 1-4 days, and the lag time of pipeline flow replenishing mine is generally 24 hours In general, the time lag of laminar flow recharge to mine is more than 2 days.

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Prediction of gas pressure in thin coal seams in the Qinglong Coal Mine in Guizhou Province, China

Journal of Petroleum Exploration and Production Technology ◽

10.1007/s13202-021-01267-2 ◽

2021 ◽

Vol 11 (11) ◽

pp. 4075-4086

Author(s):

Jian Zhang ◽

Yongqiang Zhang ◽

Jilin Wang ◽

Xiaobin Wen

Keyword(s):

Coal Seam ◽

Large Deviation ◽

Gas Pressure ◽

Guizhou Province ◽

Burial Depth ◽

Coal Seams ◽

Measuring Point ◽

Coal Structure ◽

Deviation Rate ◽

Structure Index

AbstractThin coal seams in mines usually lack gas data. Thus, preventing and controlling gas outbursts of thin coal seams are difficult. In this study, a coal structure index, which is used to express the damage degree of coal, was estimated by logging curve. In accordance with the contour line of the floor of the coal seam, structural curvature was calculated to express the complexity of the coal seam structure quantitatively. Subsequently, relationships among the burial depth, thickness, coal structure index, structural curvature were analyzed on the basis of the gas pressure of coal seam. The gas pressure values of the coal seams of Nos. 22, 24, and 27 in the study area were predicted by multiple linear regression (MLR) and were then verified and analyzed. The deviation rate of the MLR method was 6.5%–19.7%, with an average of 13.0%. The average deviation rate between the predicted value and the measured value was 11.6%, except for the measuring point of No. 2, which had a large deviation. Results show that the prediction accuracy of the aforementioned method is acceptable and has practical value in the prediction of gas pressure in thin coal seams without measured data. The results in the gas pressure prediction provide a basis for evaluating the risk of gas outbursts in thin coal seams.

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Prediction of Gas Pressure in Thin Coal Seams in the Qinglong Coal Mine in Guizhou Province, China

10.21203/rs.3.rs-139132/v1 ◽

2021 ◽

Author(s):

Jian Zhang ◽

Yongqiang Zhang ◽

Jilin Wang ◽

Xiaobin Wen

Keyword(s):

Coal Seam ◽

Large Deviation ◽

Gas Pressure ◽

Guizhou Province ◽

Burial Depth ◽

Coal Seams ◽

Measuring Point ◽

Coal Structure ◽

Deviation Rate ◽

Structure Index

Abstract Thin coal seams in mines lack gas data; thus, gas outbursts of thin coal seams are difficult to prevent and control. In this study, a coal structure index, which is used to express the damage degree of coal, was estimated by logging curve. In accordance with the contour line of the floor of the coal seam, structural curvature was calculated to quantitatively express the complexity of the coal seam structure. Then, the relationships among the burial depth, thickness, coal structure index, structural curvature, with gas pressure of coal seam were analyzed. The gas pressure of coal seam of Nos. 22, 24, and 27 in the study area was predicted by multiple linear regression (MLR) and then was verified and analyzed. The deviation rate of the MLR method was 6.5%–19.7%, with an average of 13.0%. The average deviation rate between the predicted value and the measured value was 11.6%, except for measuring point of No. 2, which had a large deviation. Results show that the prediction accuracy of the above method is acceptable, and it has practical value in the prediction of gas pressure in thin coal seams without measured data. Results of the gas pressure prediction provide a basis for evaluating the risk of gas outbursts in thin coal seams.

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Water inflow characteristics of coal seam mining aquifer in Yushen mining area, China

Arabian Journal of Geosciences ◽

10.1007/s12517-021-06535-3 ◽

2021 ◽

Vol 14 (4) ◽

Author(s):

Zhao Chunhu ◽

Jin Dewu ◽

Wang Qiangmin ◽

Wang Hao ◽

Li Zhixue ◽

...

Keyword(s):

Coal Seam ◽

Mining Area ◽

Water Inflow ◽

Seam Mining

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Prediction of Mine Water Inflow Based on Support Vector Machine

2011 Workshop on Digital Media and Digital Content Management ◽

10.1109/dmdcm.2011.17 ◽

2011 ◽

Author(s):

Wenxue Wei ◽

Longqing Shi ◽

Xinming Lu ◽

Feng Zhang

Keyword(s):

Support Vector Machine ◽

Mine Water ◽

Water Inflow ◽

Support Vector

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Application of idealised analytical techniques for prediction of mine water inflow

Mining Science and Technology ◽

10.1016/s0167-9031(85)90346-9 ◽

1985 ◽

Vol 2 (2) ◽

pp. 131-138 ◽

Cited By ~ 8

Author(s):

R.N. Singh ◽

A.S. Atkins

Keyword(s):

Mine Water ◽

Analytical Techniques ◽

Water Inflow

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Study on Reservoir Properties and Critical Depth in Deep Coal Seams in Qinshui Basin, China

Advances in Civil Engineering ◽

10.1155/2019/1683413 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7

Author(s):

Guiqiang Zheng ◽

Bin Sun ◽

Dawei Lv ◽

Zhejun Pan ◽

Huiqing Lian

Keyword(s):

Coal Seam ◽

Step Change ◽

Gas Content ◽

Burial Depth ◽

Critical Depth ◽

Coal Seams ◽

Reservoir Properties ◽

Qinshui Basin ◽

Geological Conditions ◽

Change Characteristics

Coalbed methane (CBM) reservoir properties and relationship of properties with burial depth were studied based on the data derived from 204 deep CBM production wells in Qinshui Basin, China. Through the study, it is found that permeability and porosity decrease with the increase of burial depth and the decreasing trend shows step-change characteristics at a critical burial depth. They also show divisional characteristics at certain burial depth. Gas content, geostress, and geotemperature increase with the increase of burial depth, and the increasing trend shows step-change characteristics and also have divisional characteristics at certain burial depth. Based on the previous study on the reservoir property changes with burial depth, three series of critical depth using different parameters are obtained through simulating the critical depth using the BP neural network method. It is found that the critical depth is different when using different parameters. Combined the previous study with the normalization of three different parameter types, the critical depth in Qinshui Basin was defined as shallow coal seam is lower than 650 m and transition band is 650–1000 m, while deep coal seam is deeper than 1000 m. In deep coal seams, the geological conditions and recovery becomes poor, so it can be defined as unfavorable zones. Therefore, other development means, for example, CO2 injection, need to be used to accelerate the deep coal methane development.

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Discrimination of mine water-inflow sources based on the multivariate mixed model and fuzzy comprehensive evaluation

Arabian Journal of Geosciences ◽

10.1007/s12517-020-05894-7 ◽

2020 ◽

Vol 13 (17) ◽

Author(s):

Jiuchuan Wei ◽

Guanghui Li ◽

Daolei Xie ◽

Gongyishan Yu ◽

Xiaoquan Man ◽

...

Keyword(s):

Mine Water ◽

Mixed Model ◽

Comprehensive Evaluation ◽

Fuzzy Comprehensive Evaluation ◽

Water Inflow

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Investigation of Hydraulic Fracturing Crack Propagation Behavior in Multi-Layered Coal Seams

Applied Sciences ◽

10.3390/app10031153 ◽

2020 ◽

Vol 10 (3) ◽

pp. 1153 ◽

Cited By ~ 1

Author(s):

Shirong Cao ◽

Xiyuan Li ◽

Zhe Zhou ◽

Yingwei Wang ◽

Hong Ding

Keyword(s):

Coal Seam ◽

Hydraulic Fracturing ◽

Crack Propagation ◽

Principal Stress ◽

Fracture Propagation ◽

Clean Energy ◽

Burial Depth ◽

Coal Seams ◽

Initiation Pressure ◽

Dip Angle

Coalbed methane is not only a clean energy source, but also a major problem affecting the efficient production of coal mines. Hydraulic fracturing is an effective technology for enhancing the coal seam permeability to achieve the efficient extraction of methane. This study investigated the effect of a coal seam reservoir’s geological factors on the initiation pressure and fracture propagation. Through theoretical analysis, a multi-layered coal seam initiation pressure calculation model was established based on the broken failure criterion of maximum tensile stress theory. Laboratory experiments were carried out to investigate the effects of the coal seam stress and coal seam dip angle on the crack initiation pressure and fracture propagation. The results reveal that the multi-layered coal seam hydraulic fracturing initiation pressure did not change with the coal seam inclination when the burial depth was the same. When the dip angle was the same, the initiation pressure linearly increased with the reservoir depth. A three-dimensional model was established to simulate the actual hydraulic fracturing crack propagation in multi-layered coal seams. The results reveal that the hydraulic crack propagated along the direction of the maximum principal stress and opened in the direction of the minimum principal stress. As the burial depth of the reservoir increased, the width of the hydraulic crack also increased. This study can provide the theoretical foundation for the effective implementation of hydraulic fracturing in multi-layered coal seams.

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