scholarly journals A Sequential Approach for Integrated Coal and Gas Mining of Closely-Spaced Outburst Coal Seams: Results from a Case Study Including Mine Safety Improvements and Greenhouse Gas Reductions

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3023 ◽  
Author(s):  
Liang Cheng ◽  
Zhaolong Ge ◽  
Jiufu Chen ◽  
Hao Ding ◽  
Lishuang Zou ◽  
...  
Keyword(s):  
Coal Mining ◽  
Mine Safety ◽  
Coal Bed ◽  
Gas Extraction ◽  
Coal Seams ◽  
Sequential Approach ◽  
Coal Mine Safety ◽  
Working Face ◽  
Protective Seam

Closely-spaced outburst coal seams (COCS) is the main condition of coal seams in southwest China, and gas disasters are one of the major problems affecting coal mine safety. Mining a protective seam and pre gas extraction are the most safety way to improve the efficiency of mining under these conditions. However, low pre-mining gas extraction efficiency coupled with the close proximity of adjacent working faces is a problem. When mining at an old working face has been completed but the new working face is not yet ready to be mined, coal-bed gasses can flow into the new working face from adjacent seams and this commonly causes methane monitoring instruments to sound an alarm. These gas extraction difficulties lead to a conflict between mine safety and profit. To solve these problems, a sequential approach for integrated coal and gas mining of closely-spaced outburst coal seams is introduced in this paper. Two fundamental principles are proposed: (1) Fully coordinating the spatiotemporal relationships between gas extraction, roadway development, and coal mining to maximize both mine safety and coal and gas production; (2) Defining a mining sequence for outburst coal seams and choosing the coal seam with the weakest outburst risk as the protective seam. A system for comprehensive gas extraction in underground coal mines is divided into four stages for gas extraction: gas extraction before coal roadway tunneling, gas extraction before coal mining, gas extraction during coal mining, and gas extraction from the goaf after coal mining. The Songzao mining area, China, is used as a case study to demonstrate the effectiveness of this model, and it brings three major benefits: it improves underground coal mine safety with physical gas accidents decreased by 66.8%, it makes underground coal-bed methane (CBM) extraction more efficient with the average gas extraction rate were respectively 45.13 m3/t and 62.4%, the highest in China, and it reduces greenhouse gas emissions equivalent to 3.5 million tonnes of carbon dioxide. This study could be used as a valuable example for other coal deposits being mined under similar geological conditions.

scholarly journals Comprehensive technical support for safe mining in ultra-close coal seams: A case study

2021 ◽  
pp. 014459872110093
Author(s):  
Wei Zhang ◽  
Jiawei Guo ◽  
Kaidi Xie ◽  
Jinming Wang ◽  
Liang Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Technical Support ◽  
Surrounding Rock ◽  
Coal Seams ◽  
Deformation Control ◽  
Hard Roof ◽  
Working Face ◽  
Close Coal Seams ◽  
Safe Mining

In order to mine the coal seam under super-thick hard roof, improve the utilization rate of resources and prolong the remaining service life of the mine, a case study of the Gaozhuang Coal Mine in the Zaozhuang Mining Area has been performed in this paper. Based on the specific mining geological conditions of ultra-close coal seams (#3up and #3low coal seams), their joint systematic analysis has been performed, with the focus made in the following three aspects: (i) prevention of rock burst under super-thick hard roof, (ii) deformation control of surrounding rock of roadways in the lower coal seam, and (iii) fire prevention in the goaf of working face. Given the strong bursting tendency observed in upper coal seam and lower coal seam, the technology of preventing rock burst under super-thick hard roof was proposed, which involved setting of narrow section coal pillars to protect roadways and interleaving layout of working faces. The specific supporting scheme of surrounding rock of roadways in the #3low1101 working face was determined, and the grouting reinforcement method of local fractured zones through Marithan was further proposed, to ensure the deformation control of surrounding rock of roadways in lower coal seams. The proposed fire prevention technology envisaged goaf grouting and spraying to plug leaks, which reduced the hazard of spontaneous combustion of residual coals in mined ultra-close coal seams. The technical and economic improvements with a direct economic benefit of 5.55 million yuan were achieved by the application of the proposed comprehensive technical support. The research results obtained provide a theoretical guidance and technical support of safe mining strategies of close coal seams in other mining areas.

scholarly journals Game Modelling and Strategy Research on Trilateral Evolution for Coal-Mine Operational Safety Production System: A Simulation Approach

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Yan Li ◽  
Yan Zhang ◽  
Haifeng Dai ◽  
Ziyan Zhao
Keyword(s):  
Coal Mining ◽  
Coal Mine ◽  
Evolutionary Game ◽  
Mining Industry ◽  
Mine Safety ◽  
First Line ◽  
Coal Mining Industry ◽  
Coal Mine Safety ◽  
Safety Production ◽  
Decision Making Behavior

In view of the particularity and high risk of coal mining industry, the decision-making behavior of multiple agents inside the coal-mine enterprise plays a very important role in ensuring the safety and sustainable development of coal mining industry. The existing literature studies on coal-mine safety production focus mainly on statically analyzing the game among the external entities such as the government, the enterprises themselves, and the employees inside the enterprise from a macro perspective,are short of research on revealing the dynamic interactions among the actors directly involved in the coal-mine accidents and also on proposals for effective interactions that will lead to improved safety outcomes. Therefore, this paper explores the use of evolutionary game theory to describe the interactions among the stakeholders in China’s coal-mine safety production system, which includes the organization, the first-line miners, and the first-line managers. Moreover, the paper also explores dynamic simulations of the evolutionary game model to analyze the stability of stakeholder interactions and to identify equilibrium solutions. The simulation results show that when certain conditions are met, the decision-making behavior of the organization, miners, and managers can evolve into the unique ideal steady state (1, 1, 1). In addition, the strategy portfolio with a relatively high initial proportion of three agents converges more quickly to an ideal state than a relatively low strategy portfolio. Moreover, the stable state and equilibrium values are not affected by the initial value changes. Finally, we find that the combination of positive incentive policies and strict penalties policies can make the evolutionary game system converge to desired stability faster. The application of the evolutionary game and numerical simulation when simulating the multiplayer game process of coal-mine safety production is an effective way, which provides a more effective solution to the safety and sustainable development of coal mining industry.

scholarly journals An Approach to Dynamic Disaster Prevention in Strong Rock Burst Coal Seam under Multi-Aquifers: A Case Study of Tingnan Coal Mine

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7287
Author(s):  
Xinxin Zhou ◽  
Zhenhua Ouyang ◽  
Ranran Zhou ◽  
Zhenxing Ji ◽  
Haiyang Yi ◽  
...  
Keyword(s):  
Rock Burst ◽  
Coal Mine ◽  
Water Inrush ◽  
Coal Seams ◽  
High Position ◽  
Integrated Method ◽  
Working Face ◽  
Strong Rock ◽  
And Control

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.

SUBSTANTIATION OF PARAMETERS OF THE EXPERIMENT WITH THREE-DIMENSIONAL COMPUTER MODELING OF THE ROCK MASS AROUND A LONGWALL

2021 ◽  
pp. 37-48
Author(s):  
Sergey Vlasov ◽  
◽  
Yavhen Moldavanov ◽  
Keyword(s):  
Rock Mass ◽  
Computer Modeling ◽  
Coal Mining ◽  
Three Dimensional ◽  
Mining Area ◽  
Practical Significance ◽  
Coal Seams ◽  
Working Face ◽  
Powered Support ◽  
The Difference

Purpose. To substantiate the parameters of computer modeling of the mining area with a step-by-step movement of the working face, as well as taking into account the changing presence of sandstones that lie in the top of the reservoir, to predict the effect of sandstones on the nature of the distribution of convergence in the longwall and the technology of working excavation in the conditions of the mines of Western Donbass. Methods. The work uses a statistical analysis of the geological and technological conditions that are inherent in the coal mining enterprises of the Western Donbass. Also, a comparison was made of the parameters of the experiment of computer modeling of past studies, on the basis of which, a combination of new features was introduced and changed, which is aimed at choosing the optimal modeling parameters. Results. The substantiation of the parameters of the modeling experiment is presented, such as: the choice of the length of the working face, the depth of development of coal seams, the distance of the working face withdrawal from the assembly chamber, the values of the thickness of sandstones that lie in the roof of the coal seams, the choice of values of the distance of occurrence of sandstones above the roof of the coal seam, as well as geometric parameters of the computer model. Based on the justification of the parameters, a plan for conducting experiments was drawn up, the number of which was 225 units. Scientific novelty. As a result of the substantiation of the parameters, an additional combination of new features in existing studies was proposed for the first time, namely, to include in the experiment the presence of coal seams in the top – sandstones with variable thickness, the distance of occurrence above the seam, several standard sizes of the length of the working face were also included, the value of the development depth, the distance of the exit of the working face from the assembly chamber. Changing the above parameters will make it possible to compare the difference in the effect of the results of each experiment separately, depending on the change in each of the parameters, as well as to understand and generalize the idea of ​​the nature and causes of emergency longwall stops associated with the landing of powered support sections “on a hard base”. Practical significance. Substantiated modeling parameters make it possible to most adequately reflect the processes occurring in the rock mass, as well as to clarify the parameters of the reference rock pressure zones, unloading zones, as well as the nature of the change in the distribution of convergence in the longwall. The data obtained as a result of modeling can be used to select and substantiate an effective method for managing the state of the rock mass around the working excavation, which will eliminate the planting of powered support sections “on a hard base”, thereby increasing the efficiency of coal mining in the Western Donbass.

Evaluation of the derivative environment in coal mine safety production systems: Case study in China

2017 ◽  
Vol 143 ◽  
pp. 377-387 ◽  
Author(s):  
Shuai Han ◽  
Hong Chen ◽  
Ruyin Long ◽  
Hui Qi ◽  
Xiaotong Cui
Keyword(s):  
Coal Mine ◽  
Production Systems ◽  
Mine Safety ◽  
Coal Mine Safety ◽  
Safety Production

scholarly journals Fracture evolution and gas transport laws of coal and rock in one kilometer deep coal mine with complicated conditions

2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 907-915
Author(s):  
Jianguo Zhang ◽  
Man Wang ◽  
Yingwei Wang
Keyword(s):  
Coal Seam ◽  
Coal Mining ◽  
Coal Mine ◽  
Fracture Zone ◽  
Gas Flow ◽  
Gas Transport ◽  
Enhancement Effect ◽  
Gas Extraction ◽  
Coal Seams ◽  
Long Distance

As coal mining gradually extends deeper, coal seams in China generally show high stress, high gas pressure and low permeability, bringing more difficulty to coal mining. Therefore, in order to strengthen gas extraction, it is necessary to carry out reservoir reconstruction after deep coal seams reached. In this paper, the distribution and evolution laws of fracture zone overlaying strata of J15 seam in Pingdingshan No. 10 coal mine after excavation were studied by combining similar simulation and numerical simulation, meanwhile, the gas transport law within fracture zone was numerically simulated. The results show that the fracture zone reaches a maximum of 350 mm in the vertical direction and is 75 mm away from W9,10 coal seams in vertical distance. Since W9,10 coal seams are in an area greatly affected by the bending zone of J15 coal seam under the influence of mining, the mining of J15 coal seam will exert a strong permeability enhancement effect on W9,10 coal seams. The J15 coal seam can act as a long-distance protective layer of W9,10 coal seams to eliminate the outburst danger of the long-distance coal seams in bending zone with coal and gas outburst danger, thereby achiev?ing safe, productive and efficient integrated mining of coal and gas resources. The gas flux of mining-induced fractures in the trapezoidal stage of mining-induced fracture field is far greater than that in the overlaying stratum matrix. The horizontal separation fractures and vertical broken fractures within the mining-induced fracture field act as passages for gas-flow. Compared with gas transport in the overlaying stratum matrix, the horizontal separation fractures and vertical broken fractures within the mining-induced fracture field play a role in guiding gas-flow. The research results can provide theoretical support for the arrangement of high-level gas extraction boreholes in roof fracture zones.

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