scholarly journals Prevention and Control of Hydrogen Sulphide Accidents in Mining Extremely Thick Coal Seam: A Case Study in Wudong Coal Mine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xuchao Huang ◽  
Enmao Wang ◽  
Gang Wang ◽  
Jiuyuan Fan
Keyword(s):  
Molecular Weight ◽  
Coal Seam ◽  
Hydrogen Sulphide ◽  
Coal Mine ◽  
Prevention And Control ◽  
Coal Mines ◽  
Dynamics Simulation ◽  
Porous System ◽  
Coal Stratum ◽  
And Control

Hydrogen sulphide is a toxic gas often present in coal seams and seriously threatens the lives and health of underground workers in coal mines. In this study, we theoretically modelled hydrogen sulphide generation in extremely thick underground coal mines with the +575 level #45 coal seam of Wudong Coal Mine as an example and obtained the on-site hydrogen sulphide emission pattern and spatial distribution features by combining field measurements and computational fluid dynamics simulation. The results showed that hydrogen sulphide mainly exists in the coal porous system in an adsorbed state. Because hydrogen sulphide has a molecular weight greater than the average molecular weight of air molecules, its concentration decreases with the increase of altitude to the bottom plate. When mining the upper stratified coal stratum, it diffuses widely in the working space; while when mining the lower coal stratum, it mainly concentrates at the bottom of the working face. Based on these analyses, on-site treatments were carried out using mixtures with different concentrations of sodium carbonate and sodium bicarbonate. In addition, different combinations of catalysts as well as type A and type B wetting agents were also tested. Eventually, a neutral KXL-I absorbent was developed, and the process of preinjecting absorbent and spraying absorbent was designed. The results showed that the newly developed KXL-I absorbent has high hydrogen sulphide absorption ability and is suitable for use as an absorbent in Wudong Coal Mine; preinjecting and spraying the absorbent can effectively prevent hydrogen sulphide disasters in the +575 level #45 coal seam in Wudong Coal Mine with the optimal final concentration of 0.9% and the absorption rate of 87% at the shearer of 66.6% at the support. Overall, our study provides valuable information for the prevention and control of hydrogen sulphide disasters in coal mines.

scholarly journals Identification of Hydraulic Connection Points between Different Confined Aquifers in the Liyazhuang Coal Mine

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zhenghe Liu ◽  
Peiyun Zhao ◽  
Lusheng Yang ◽  
Jingui Zhao ◽  
Hailong Ye ◽  
...  
Keyword(s):  
Flow Field ◽  
Coal Seam ◽  
Numerical Simulations ◽  
Water Level ◽  
Coal Mine ◽  
Prevention And Control ◽  
Water Inrush ◽  
Hydraulic Connection ◽  
Contact Points ◽  
And Control

Water inrush from coal seam floors is one major geological obstacle hindering safe and efficient production activities in mines. Determining the source of water inrush can facilitate its prediction and guide decisions regarding measures for prevention and control. The process of identifying the location of hidden hydraulic contact points in different confined aquifers forms the basis of hydrogeological explorations. It is also the basis for categorizing mine areas prone to water inrush and making qualitative decisions regarding the prevention and control of water inrush. In this study, the positions of hidden hydraulic contact points between the Ordovician Fengfeng and Shangmajiagou formations in the basement of the Liyazhuang coal mine were determined using numerical simulations of the flow fields. First, each node of the finite element grid was considered as a water inrush point to determine the water level at other nodes. Subsequently, the error between measured and simulated water levels, determined based on the flow fields, was determined using the least squares method. The node with the minimum error was then considered as the hidden hydraulic contact point. The simulation results for the flow field indicate a distance of 5000 m between the hydraulic connection and the water inrush points located between the peak formation and the Majiagou aquifer in the Liyazhuang coal mine. Furthermore, the hydraulic relationship between them is poor. Observational data of water inrush from the floor of the No. 2 coal seam and the water level of the confined aquifer in the Liyazhuang coal mine, including the water quality test data of different Ordovician ash aquifers, show that the source of water inrush from the floor of the No. 2 coal seam is the aquifer of the Fengfeng Formation. This finding is consistent with the results of the numerical simulations of the flow field. The results demonstrate that, in mining areas subjected to high pressures, numerical simulations of the flow field can serve as an effective tool for determining the location of hidden hydraulic contact points.

scholarly journals Analysis on the Development Status of Coal Mine Dust Disaster Prevention Technology in China

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hui Zhang ◽  
Weihai Han ◽  
Youlin Xu ◽  
Zhenfeng Wang
Keyword(s):  
Coal Mine ◽  
Prevention And Control ◽  
Occupational Diseases ◽  
Coal Mines ◽  
Control Measures ◽  
Dust Removal ◽  
Dust Collector ◽  
Mine Dust ◽  
Mining Face ◽  
And Control

In recent years, with the increasing level of mechanization, automation, and intelligence in mine mining, dust pollution in the working environment of coal mines has become increasingly serious. Coal mine dust prevention is an important work related to the life, health, and production safety of miners, and it is also one of the technical problems of mine safety in production. With the continuous revision and improvement of China′s Occupational Disease Prevention and Control Law, coal mining enterprises have generally strengthened the publicity, prevention, and control of occupational diseases among employees, and the control of coal mine dust has been used as a means for enterprises to improve the production environment and strengthen the occupational health of employees. Key work-based studies have shown that China’s coal mines have formed a theoretical system and technology system of dust prevention and control. In the future, China’s coal mines will start from intelligent dust prevention, achieve high-precision dust sensing-transmission-assessment and early warning, and develop a combined dust collector that integrates the functions of atomization dust removal, miniaturization, dry and wet mixing, and large air suction capacity. The combined dust collector realizes the efficient ventilation control and dust removal of the fine dust in wide-area complex spaces such as fully mechanized mining face and fully mechanized mining face. At the same time, breakthroughs have been achieved in low-permeability coal seams, such as strong hydraulic permeability-enhancing technology, intelligent dust-proof robots, and chemical dust suppression. This article introduces the basic concepts, generation, distribution, and hazards of coal mine dust and analyzes the characteristics, applicable conditions, and use effects of various dust control measures such as ventilation dust removal and wet dust removal. Moreover, this article also proposes specific prevention and control measures for related occupational diseases and discusses the development trend of dust prevention and control technology in the hope of providing guidance and reference for coal mine dust prevention and control.

scholarly journals System for Prevention and Control of Old Goaf Water during Coal Mine Re-mining

2021 ◽  
Author(s):  
Shuning Dong ◽  
Xiaolong Li ◽  
Liuzhu Ma
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Prevention And Control ◽  
Small Scale ◽  
Target Area ◽  
Geophysical Exploration ◽  
Blind Area ◽  
Mining Face ◽  
And Control ◽  
Water Disaster

Abstract One integrated mine was currently threatened with an old goaf water disaster, therefore, the development of an advanced detection-guarantee system for roadway excavation with no blind area was imperative. Further, multiple geophysical exploration in combination with two types of boreholes were used to explore and drain water technology, with the anomalous geophysical area as the target area, The conventional borehole with the largest water outflow was taken as the target spot, at a low elevation of the mining area, and a remote directional borehole was used to drill into the old goaf along the stable rock strata below the coal seam floor to intercept the dynamic recharge water, which increased the efficiency of roadway excavation 4–9 times. The ‘isolated island’ old goaf water in the mining face was controlled through multiple geophysical exploration combined with the full-coverage exploration technology by conventional boreholes, and the water-rich anomalous area and geological anomalous area were determined, thus ensuring the safety of the mining face in terms of old goaf water. The technology for advanced short-distance exploration, advanced estimate, roadway exploration, and dynamic old goaf water with drainage was used to comprehensively guarantee real-time, safe mining. This system for the prevention and control of old goaf water was applied to a control project for the old goaf water disaster in the 101 mining face. At present, 1.37 Mt of coal has been safely mined from this mining face. The technical system has improved The Detailed Rules for Water Disaster Prevention and Control of Coal Mine (NCMSA 2018), and improved the technology for the prevention and control of old goaf water under conditions where the upper portion in the same coal seam was destroyed by a small-scale coal mine and re-mining.

scholarly journals Cause Analysis and Prevention of Hole Collapse by Water Injection and Dust Removal in Qi Panjing Coal Mine

Geofluids ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Hua Guo ◽  
Hai-Qiao Wang ◽  
Shi-Qiang Chen ◽  
Zhi-Rong Wu
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Prevention And Control ◽  
Water Injection ◽  
Economic Benefits ◽  
Dust Removal ◽  
Drilling Depth ◽  
Key Technologies ◽  
Complete Set ◽  
And Control

To solve the “special coal seam” with complex coal seam structure, fault phenomenon, and many gangue layers and complex gangue lithology in Qi Panjing coal mine, the problems such as hole collapse and blockage of coal seam water injection dust removal drilling are caused. From the aspects of drilling layout, drilling technology, and gangue material consolidation, a complete set of key technologies for prevention and control of water injection and dust removal in “special coal seam,” have been formed. Seven boreholes have been drilled in I020902 return air roadway of Qi Panjing coal mine, and field comparative test has been carried out. The results show that: after adopting the complete set of key technologies of drilling prevention and control, the drilling depth is 85-100 m, the average depth is 98 m, and the drilling depth of coal seam water injection can reach 170-185 m; the footage per cycle is greatly improved, with the minimum increase of 30.86%, the maximum increase of 46.38%, and the average increase of 36.77%, to save drilling time and bring good economic benefits, and there is no collapse in the borehole hole, to ensure the safety of production. It has a good reference, and practical guiding significance for other coal mining faces, especially for “special coal seam” working face.

scholarly journals Typical Cases of Groundwater Pollution and Control Strategies for Closed Coal Mine in China

2020 ◽  
Author(s):  
Qiyan Feng ◽  
Lai Zhou ◽  
Yongping Liang ◽  
Jianwei Zhou ◽  
Hujun Ren ◽  
...  
Keyword(s):  
Coal Mine ◽  
Mine Water ◽  
Groundwater Pollution ◽  
Prevention And Control ◽  
Coal Mines ◽  
Pollution Prevention ◽  
Mining Area ◽  
Water Infiltration ◽  
Geological Conditions ◽  
And Control

Abstract Due to the coal resource depletion, complicated geological conditions, and policy adjustment of China coal mine industry, a large number of coal mines have been closed and abandoned. The rebound of groundwater level will cause flooding of goaf and roadways after mine closure. The hydrogeological conditions change significantly as well. The pollutants will leach out, transform and transport which lead to pollution and increase risk to the groundwater system in the mining area. This research investigated closed coal mining area in Xuzhou, Zibo, Fengfeng, Kaili, Yangquan, Doulishan, Huaibei, Jiaozuo, Jingxing, Mile, etc., to present typical cases for analyzing the featured pollutants in mine water. Eight groundwater pollution pathways were summarized in closed coal mines, including pollution infiltration from surface mining fissures; submerged water infiltration pollution; leaching pollution of surface solid waste; cross strata pollution from the diversion fissure zone in the mining roof; cross strata pollution through the mining fissures in the mining floor; cross strata pollution through the water-conducting wells; cross strata pollution of faults or collapse columns; water overflow from goaf. Three typical cases on cross strata pollution in the closed/abandoned coal mine were analyzed emphatically. Aiming at the prevention and control of groundwater pollution risk in coal mine, the technical ideas of reducing quantity and pollutant of mine water, channel blocking, extraction control, purification and utilization are put forward. Based on this idea, the main pollution prevention and control technologies are recommended, and the countermeasures for the environmental protection of groundwater in closed mine are proposed.

scholarly journals Discussion on Some Topical Issues of Water Prevention and Control in Coal Mines

2021 ◽  
Author(s):  
Shuning Dong ◽  
Wenzhong Zhang ◽  
Wanfang Zhou ◽  
Rui Chai ◽  
Hao Wang ◽  
...  
Keyword(s):  
Prevention And Control ◽  
Coal Mines ◽  
And Control

scholarly journals Controlling Mechanism of Rock Burst by CO2 Fracturing Blasting Based on Rock Burst System

2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Tianwei Lan ◽  
Chaojun Fan ◽  
Jun Han ◽  
Hongwei Zhang ◽  
Jiawei Sun
Keyword(s):  
Coal Mining ◽  
Rock Burst ◽  
Coal Mine ◽  
Prevention And Control ◽  
Stress Measurement ◽  
Tectonic Stress ◽  
Microseismic Monitoring ◽  
Time Space ◽  
Controlling Mechanism ◽  
And Control

Rock burst induced by mining is one of the most serious dynamic disasters in the process of coal mining. The mechanism of a rock burst is similar to that of a natural earthquake. It is difficult to accurately predict the “time, space, and strength” of rock burst, but the possibility of rock burst can be predicted based on the results of microseismic monitoring. In this paper, the rock burst system under the tectonic stress field is established based on the practice of coal mining and the result of mine ground crustal stress measurement. According to the magnitude of microseismic monitoring, the amount of the energy and spatial position of the rock burst are determined. Based on the theory of explosion mechanics, aiming at the prevention and control of rock burst in the coal mine, the technique of liquid CO2 fracturing blasting is put forward. By the experiment of blasting mechanics, the blasting parameters are determined, and the controlling mechanism of rock burst of liquid CO2 fracturing blasting is revealed. The application of liquid CO2 fissure blasting technology in the prevention and control of rock burst in Jixian Coal Mine shows that CO2 fracturing blasting reduces the stress concentration of the rock burst system and transfers energy to the deeper part, and there is no open fire in the blasting. It is a new, safe, and efficient method to prevent and control rock burst, which can be applied widely.

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