Roof Accidents Research Articles

Analysis of the causes and safety countermeasures of coal mine accidents: A case study of coal mine accidents in China from 2018 to 2022

Statistical data on coal mine safety accidents in China from 2018 to 2022 were obtained. Mathematical statistical methods were used to analyze the accident level, accident type, death toll, time, space, and other factors. Grounded theory (GT), case-based reasoning (CBR), analytic hierarchy process (AHP), interpretative structural model (ISM) and other methods were used to analyze the causes of coal mine accidents in detail, and the characteristics, accident-causing attributes and importance of coal mine accidents in China were explored. The results indicate that (1) according to the level and type of accident, the incidence of general accidents in coal mines is the highest, with both the number of roof accidents and the death toll accounting for the highest values. From the time and location of the accidents, coal mine accident-prone areas are concentrated in northern and southern China. May and July are accident-prone periods every year. (2) Using GT-CBR to analyze the causes of coal mine accidents, 18 key statements were extracted, and 11 initialization concepts were summarized. Ultimately, the causes were categorized into 4 core categories: human factors (H), machine factors (M), environmental factors (E), and organizational management factors (O). (3) A hierarchical structure model of the causes of accidents according to ISM was built. The weight and proportion of accidents and deaths were combined to evaluate the importance of accident-causing attributes. Human factor-induced accidents accounted for 71.6 % of all accidents, and the number of accident death caused by organization management factors was the largest, accounting for 54.8 %. Comprehensive analysis revealed that human and organization management factors are the most important causes of coal mine accidents

Mechanism of rockburst induced by roadway repair under intense mining: a case study

Rockbursts involve a sudden failure of the coal and rock mass without any apparent macroscopic precursors, threatening the production safety of coal mines. Achieving precise prediction of potential seismic body of rockbursts and determining their inducing factors are essential for effective prevention and control of rockbursts. By investigating the “1.17” major roof accident in the Danshuigou mine, the distribution characteristics of potential high-energy seismic body in the accident roadway during multi-layer mining were studied, relationship between these characteristics and the surrounding rock damage was established, and mechanism of the high-energy seismic body-induced rockbursts in the roadway was elucidated. It was found that the repair of the roadway floor was a key factor inducing the rockburst occurrence, with multi-layer mining generating potential high-energy seismic body reaching energy densities up to 106 J/m3, resulting in roadway collapse and severe damage. Greater energy in these seismic body correlates with higher degrees of roadway impact damage. Moreover, higher energy accumulation in surrounding rock during roadway repairs leads to greater energy release. The triggering effects of roadway floor repair construction result in the instantaneous release of large elastic energy accumulated in ultrahigh-energy coal rock bodies, causing rock mass impact damage during triple mining. This study significantly contributes to understanding rockburst mechanisms and enhances the effectiveness of rockburst prediction and prevention.

Coal mine roof accident causation modeling and system reliability research based on directed weighted network

Coal mine roof accidents have frequently caused massive casualties and economic losses. To understand the mechanism of roof accidents, 205 roof accidents in China from 2013 to 2022 were selected, and a total of 44 accident causal factors were identified, including the human-material-environment-supervisory and the final causal factor, and each causation chain was analyzed. Accordingly, a complex network is used to construct a causation network model for roof accidents, and the structural characteristics of the network are analyzed to obtain the key causal factors and important inter-causal relationships. Combined with the robustness analysis, three different intentional attacks are selected, and it is found that the proposed three methods significantly reduce the network efficiency compared with the random attack, and the deliberate attack based on the degree ranking has the best effect, which indicates that the developed method can effectively identify the causes of accidents. This study provides an important basis for the decision-making of coal mine roof accident prevention and reveals the difficulties of accident prevention, and also provides ideas and references for the study of accident mechanism and the construction of accident causation network model using complex networks.

A new fusion method to predict coal mine roof accidents

AbstractIn the context that coal remains the main energy source of China now, the safety of coal mine production is still worth our attention. For the factors influencing the roof accident of coal mine roadway have great complexity and uncertainty, a new risk prediction method of coal mine roof accidents integrating T‐S fuzzy fault tree and Bayesian network (BN) is proposed. The constructed method determines the BN and the conditional probability tables according to the established T‐S fuzzy fault tree. The fault state and fuzzy fault rate of root nodes are described according to the fuzzy number. And the forward inference of Bayesian is used to calculate the probability of the accidents on the roadway roof based on the fault probability of the root nodes and actual fault probability during construction respectively, to realize the risk prediction of roof accidents. Finally, practical data are used to verify the new fusion risk evaluation method by taking two mines as cases. The results show that the influencing factors calculated by the new fusion risk prediction method are completely consistent with the actual situation, confirming the effectiveness and reliability of this method, which providing new ideas for the research about the risk prediction of coal mine roof accidents.

Energy Accumulation Characteristics and Induced Rockburst Mechanism of Roadway Surrounding Rock under Multiple Mining Disturbances: A Case Study

The source of energy release when rockburst occurs must be determined to understand the mechanisms underlying disaster formation and achieve accurate prevention and control. Although previous research has systematically investigated the energy source underlying rockburst from different perspectives, issues such as an unclear understanding of the energy accumulation state and inaccurate positioning of the energy release source remain to be resolved. In this study, the “1·17” major roof accident in the Danshuigou Mine was used as the background to evaluate and analyze the stress environment and energy accumulation characteristics of roadway surrounding rock under multiple mining disturbances, and the results showed that a super energy package occurs in the surrounding rock of the mining roadway. Subsequently, the evolution process of energy in this region and the mechanism of induced rockburst were elaborated. The results showed that the degree of stress concentration in the surrounding rock of the roadway will increase several times as the number of mining disturbances increases. Under the influence of multiple mining disturbances, the maximum principal stress peak of the surrounding rock of the roadway can reach 5–10 times the maximum principal stress value outside the mining-affected area. A large amount of elastic energy was accumulated in the rock surrounding the roadway, and super-high-density energy packages were formed locally. The maximum energy density value reached 50–185 times the value observed in areas outside the mining-affected zone. Thus, rockburst may be induced when the large amount of energy accumulated in the super energy package is suddenly and violently released; moreover, the degree of energy accumulation in the super energy package is likely closely related to the magnitude of rockburst. These results have important theoretical significance and application value for clarifying the mechanism of rockburst and improving the effectiveness of rockburst prediction and prevention.

Failure analysis and prediction of roof instability in end face under repeated mining using early warning system

The overlying strata of the lower coal seam is easy to be collapsed causing the roof caving accident at the end face of the mining working face under repeated mining in close-distance coal seams. In order to predict the roof instability of the end face, the mechanical model of the granular arch structure is established in this study to further analyze its main influencing factors. The results show that the mining height of the working face, the advancing speed, the distance of coal seams, the tip-to-face distance, the strength of the surrounding rock and the support setting the load of the support are the main influencing factors on the roof caving of the end face. Subsequently, the prediction model of roof instability in the end face under repeated mining is constructed through the radial basis function neural network (RBFNN) and the above main influencing factors are regarded as input layer indexes. Meanwhile, the roof subsidence, coal wall deformation and support load are determined as the output layer indexes. The predicted results are closer to the results of sample tests. Finally, the early warning system, including monitoring and early warning, data query, emergency management, user management, and system settings, is designed to monitor roof conditions of the end face and timely warn the roof accidents. The field application proves that the system has good practical value, which is of great significance to intelligent prediction of coal mine stope disaster and prevent the end face roof disaster under repeated mining and. This will promote the safe and efficient construction of coal mine production.

Application of Bayes Theorem to Accident Analysis and Classification

In today's social context, "data" is a very common term. Data Science, Data analysis and other applications on different levels of Data have become very popular topics and even jobs. The main topic to be analyzed in this paper is Bayesian theorem. Bayesian theorem is a basic theorem in statistics, but with sufficient data support, Bayesian theorem can be applied in many fields. In this paper, this paper will analyze the application of Bayes' theorem in these two aspects: Bayes Theorem to Accident Analysis and Bayes Theorem to Classification. In terms of Bayes Theorem to Accident Analysis, this paper will analyze three papers that use Bayesian theorem to analyze accidents. In these papers, the authors have used Bayesian theorem to analyze different accidents. These accidents are: The causes and analysis of engineering accidents in mining areas, the analysis of causes of roof accidents in coal mines, and the analysis of the causes of highway traffic accidents. way of accident. In terms of Bayes Theorem to Classification, most of the authors use naive bayes to classify different data sets. The benefits of this classification are that whenever new data enters, researchers can easily classify new data sets. Incoming data is categorized.

Research on Mining Pressure Dynamic Effect of the Large Dip Angle Working Face

In order to study the mining pressure law of the large dip angle working face, prevent the topping accident of the working face, and cause the roof accident, through the observation of the mining pressure of the working face of Xiaogou coal mine, the law of mine pressure appearance and dynamic effect of the large dip angle working face are obtained. The results show that the initial support force of the working face support is not less than 24 MPa, the lower part of the working face is larger, and the falling rock has not been effectively filled in the middle and lower part of the working face. Therefore, the daily observation of the top and bottom goaf is carried out to determine whether it is a large area of suspended ceiling appears. Taking effective measures for safe mining in a timely manner has great practical significance for reducing roof accidents.

The Ra&D of Automatic Mobile Emergency Rescue Support System for Coal Mine Roadway Roof

Coal mine roadway roof accidents occur frequently, but the emergency rescue research after roof accidents is too one-sided. This paper proposes out an innovative rescue channel system that can be formed quickly in the roof area. The system is mainly composed of two parts: support frame and traction frame. Experimental applications were carried out in coal mines. The application results show that the rescue channel has many advantages such as fast movement, high support strength, light weight and easy to carry, which can achieve the purpose of rapid emergency rescue and ensure the safe and efficient production of the mine.

The Ra&D of Automatic Mobile Emergency Rescue Support System for Coal Mine Roadway Roof

Coal mine roadway roof accidents occur frequently, but the emergency rescue research after roof accidents is too one-sided. This paper proposes out an innovative rescue channel system that can be formed quickly in the roof area. The system is mainly composed of two parts: support frame and traction frame. Experimental applications were carried out in coal mines. The application results show that the rescue channel has many advantages such as fast movement, high support strength, light weight and easy to carry, which can achieve the purpose of rapid emergency rescue and ensure the safe and efficient production of the mine.

Study on Safety Management Assessment of Coal Mine Roofs Based on the DEMATEL-ANP Method

Coal mine roof accidents are one of the main single risks faced by coal miners. According to the statistical data of coal mine accidents in China, there were 40 roof accidents and 55 deaths in 2020 alone, accounting for 32.8 and 24.4% of the total, respectively. Therefore, we can see its danger. To realize the comprehensive scientific assessment of coal mine roof accidents, first, through the collation and analysis of relevant literature reviews and accident investigation reports, combined with the expert investigation method, an assessment index system of coal mine roof accidents is constructed. Then, based on the analysis of the characteristics of the influencing factors of coal mine roof accidents, the assessment model of coal mine roof accidents is established by using the DEMATEL-ANP method. Finally, the established assessment model is applied to a coal mine to verify the rationality of the model.

Structural Characteristics of Regenerated Roof and Distribution Law of Overburden Porosity in Downward Mining of a Bifurcated Coal Seam

During downward mining of a bifurcated coal seam, the roof of the lower coal seam is relatively broken and difficult to control due to the mining influence of the upper coal seam. Roof accidents occur frequently during mining of the lower coal seam, reducing mining efficiency. How to ensure safe and efficient mining of the lower coal seam is a significant issue. In this paper, overlying strata migration and fracture characteristics of the lower coal seam, the structure and stability of the regenerated roof, and porosity and permeability characteristics of the overlying strata under the mining influence of the upper coal seam are studied by using similar simulation tests. Results show that the overburden structure of the lower coal seam is altered due to the mining influence of the upper coal seam, and the regenerated roof of the lower coal seam is divided into three structural types from top to bottom, namely: intact rock mass+block fracture rock mass+loose rock mass (type I structure); intact rock mass+block fracture rock mass+loose rock mass+cataclastic rock mass (type II structure); and intact rock mass+block fracture rock mass+loose rock mass+cataclastic rock mass+slab-rent rock mass (type III structure). The stability of each type of rock mass structure is evaluated, and the stability of three types of rock mass structures is III > II > I. The overburden porosity and slurry permeability coefficient are relatively large at the cutting hole and stopping line. The porosity of the caving zone within 70 m of the cut hole and stopping line is greater than 5%, and the permeability coefficient is greater than 0.1 m/s. Based on differences in the surrounding rock porosity and permeability characteristics, the grouting difficulty of overburden is divided into three types of areas: extremely easy grouting areas, easy grouting areas, and difficult grouting areas. The results of this paper can provide reference for the stability evaluation of the regenerated roof and the selection of grouting treatment parameters for the broken roof under similar conditions.

The Comprehensive Identification of Roof Risk in a Fully Mechanized Working Face Using the Cloud Model

Roof accidents seriously affect the safe and efficient mining of the working faces. Therefore, it is necessary to assess and identify the possible and influencing factors on the occurrence of roof risk in a fully mechanized mining workface. In this study, based on the analytic hierarchy process and fuzzy comprehensive evaluation, a comprehensive standard cloud model was established through constructing a quantitative grade interval and calculating the weight of each index to achieve the aim of a roof risk assessment and identification. The accuracy of risk assessment was ensured by using the comprehensive analyses of various aspects, such as cloud digital features, risk assessment cloud image and standard cloud image. This showed that the main influencing factors on the occurrence of roof accidents were roof separation distance, weighting intensity and rib spalling followed by the coal body stress concentration, initial support force and geological conditions. Taking 42,115 fully mechanized working faces in the Yushen coal mining area as an engineering background, this model was adopted to assess and identify the risk of roof accidents through generating comprehensive assessment cloud images and introducing the Dice coefficient to calculate the similarity degree. The results showed that the overall risk of roof accidents in 42,115 working faces was regarded as grade II (general risk) through the overall index of comprehensive risk evaluation and a similarity degree of 0.8606. The impact of roof condition was mainly influenced by the risk of roof accidents, while the support status, personal working status and coal body condition had a limited effect on the risk of roof accidents. The comprehensive standard cloud model proposed in this study had strong visibility and discovered the key parts of risk indexes easily to solve the problems of ambiguity and quantitative identification in traditional roof risk evaluation methods. Therefore, this model was worth promoting, because it laid the foundation for the intelligent identification and early warning system of roof accident risk in a fully mechanized mining workface.

From aggregate to part: Study on the change of coal mine safety records in China under the intervention of risk pre-control management system

Risk pre-control management is of great significance to the safe production of China's coal-mining industry, so it is necessary to clarify the role and existing problems of the current risk pre-control system in China's coal-mining enterprises. On the basis of expounding the background and mechanism of the risk pre-control system, this paper first evaluates the overall intervention effect of the system by constructing an interrupted regression model, and then analyzes the prevention effect of the system on coal mine accidents by category, finding out the urgent needs for improvement. The results suggest that the establishment of risk pre-control management system has no obvious effect on the improvement of coal mine safety records in the short term, but has a significant positive effect in the long run. Moreover, since the construction of the system, its intervention effect on roof accidents, transportation accidents, flood accidents and other accidents is tremendous, while the effect on gas accidents and electro-mechanical accidents is weak, and the control of fire accidents is the worst. Finally, from the system construction process and the nature of accidents, this paper puts forward the corresponding safety management suggestions and accidental prevention measures to further improve the quality of risk pre-control management in China.

Characteristics and trends of coal mine safety development

ABSTRACT During the “12th Five-Year Plan” period (2011–2015), the safety production situation of coal mines in Guizhou province was generally good. The main types of accidents are gas, flood and roof accidents. The average fatalities for each type of accident were 6.2, 6.8 and 1.2, respectively. During the “12th Five-Year Plan” period, 45 gas accidents occurred and 277 people died, accounting for 18.03% and 48.94% of the total accidents, respectively; 10 flood accidents caused 68 deaths, accounting for 4.1% and 12.01% of the total accidents, respectively; 106 roof accidents caused 129 deaths, accounting for 43.44% and 22.79% of the total accidents, respectively. The number of accidents and casualties is decreasing year by year. Compared with 2015 and 2010, the number of accidents and fatalities decreased by 213 and 324, decreased by 96.82% and 95.27%, respectively. The accident rate of state-owned coal mines was relatively high, and the rate of decline was higher than that of private coal mines. After 2012, the accident rate of production mines was lower than that of construction mines, and preventive measures were explained in terms of safety law enforcement, supervision and technology. The research results have certain reference significance for the government supervision departments to strengthen coal mine safety production, and help to take safety precautions to avoid coal mine accidents.

Experimental Study on the Displacement Sensor of Coal Roadways Roof Settlement Based on Distributed Fiber Optic Sensing

Roof displacement monitoring is an important means to ensure roof stability and prevent roof accidents of Coal Roadways (CRs). In this paper a new sensor of roof settlement displacement (RSD) monitoring of CRs' roof by the pre-stretched optical fiber (PSOF) laid out horizontally at fixed points was proposed. The principle of the sensor is to qualitively and quantitively characterize the RSD by the Fiber Optic Strain (FOS) which is measured based on distributed fiber optic strain measurement. Through theoretical analysis, the mathematical expression for quantifying RSD is derived. The correctness of the sensor is verified by the indoors FOS experiments and the field monitoring of CRs' roof in Yinying Coal Mine. This new sensor can be applied not only to the roof of CRs, but also to the displacement monitoring of other structures with the similar settlement presentation.

Experimental and numerical investigation of energy dissipation of roadways with thick soft roofs in underground coal mines

AbstractThe roadway deformation process is closely associated with the accumulation and dissipation of energy. Understanding the characteristics of energy dissipation in surrounding rock is critical to revealing the development process and the disaster mechanisms of the roof accidents in underground coal mines. This paper presents a triaxial compression experiment to analyze energy characteristics of mudstone taken from Huangyanhui Coal Mine. A numerical study is performed to study the energy distribution under different roof strengths. The results suggest that the instability of the roadway is an irreversible energy dissipation process with high nonlinearity and complexity. The roadway support principle, based on the energy balance theory, is proposed to explain the energy distribution. The safety control of roadways with thick and soft roofs should consider the following three aspects: (a) optimize the layout of the roadway, avoid placing it in the stress concentration zone, and reduce the strain energy of the surrounding rock accumulation from the source; (b) improve the ability of the supporting structure to adapt to the deformation of the surrounding rock and avoid the failure of the supporting structure because of excessive force; and (c) set weak structures in the surrounding rock, that dissipate part of the energy, thus reducing the load acting on the support. The results of field application monitoring show that roadway severe deformation was effectively controlled using pressure relief boreholes (PRB), and the average floor heave speed of the roadway decreased from the original 2.0 to 0.98 mm/d. Therefore, PRB provides a new approach for roadway control.

Safety evaluation of mine roof accident based on grey fuzzy comprehensive evaluation

By analyzing the risk assessment methods of roof accidents at home and abroad, this paper summarizes the research status of risk assessment in this area, and analyzes the significance of risk assessment of mine roof accidents. The risk identification of roadway collapse accident is carried out from four aspects -- human, material, environment, and management, and the risk evaluation index system is established, including human unsafe behavior, material unsafe state, management factors and environmental factors. On this basis, the weight of index set is determined by grey relation analysis, and the fuzzy comprehensive evaluation model is obtained by combining the fuzzy comprehensive evaluation method. Taking a coal mine as an example, this paper makes an empirical study of risk assessment and puts forward corresponding countermeasures according to the results of comprehensive assessment. The results show that the safety level of the mine is very safe, so it is feasible to use the grey fuzzy comprehensive evaluation method to evaluate the safety of the mine, which can provide reference for the same kind of mine.

Analysis of Coal Mine Roof Accident and Research on Prevention Countermeasures

Analysis of Coal Mine Roof Accident and Research on Prevention Countermeasures

Physical model test study on support of super pre-stressed anchor in the mining engineering

With the increase in mining depths, support problems of anchor such as roof accidents and large deformation of soft rock are becoming more and more prominent. Whether the anchor is suitable for deep roadway support has been questioned. In order to explore this problem, this paper studies the ultimate support effect of super pre-stressed anchors. Based on current higher pre-stress support technology in mining engineering, a support scheme of super anchor is proposed and investigated. In this work, the super anchor scheme and the other two schemes were compared and analysed through a physical model test. The model’s displacement data was recorded by a high-speed camera. Meanwhile, the numerical model with the same conditions is calculated. The results show that, the super anchor scheme can improve the stress distribution of the surrounding rock; and this method contributes to the optimization of the support parameters and improves the roof bearing capacity. In addition, the super anchor scheme has a smaller scope of damage than the other two schemes. Third, the super anchor scheme reduces the number of anchors without reducing the strength of the support, which is beneficial to the rapid excavation of the roadway. However, it is worth noting that, the end of the super anchor will produce significant stress concentration in the support process, and this easily leads to the separation and crack of the roof near the end of the super anchor. In short, the physical model test shows that, using super pre-stressed anchors is promising for solving the extremely difficult deep roadway support problems.