Coal Mine Safety Production Research Articles

Research on Automatic Classification of Coal Mine Microseismic Events Based on Data Enhancement and FCN-LSTM Network

Efficient and accurate classification of the microseismic data obtained in coal mine production is of great significance for the guidance of coal mine production safety, disaster prevention and early warning. In the early stage, the classification of microseismic events relies on human experiences, which is not only inefficient but also often causes some misclassifications. In recent years, the neural network-based classification method has become more favored by people because of its advantages in modeling procedures. A microseismic signal is a kind of time-series signal and the application of the classification method is widely optimistic. The number and the balance of the training data samples have an important impact on the accuracy of the classification result. However, the quality of the training data set obtained from the production cannot be guaranteed. A long short-term memory (LSTM) network can analyze the time-series input data, where the image classification at the pixel level can be achieved by the fully convolutional network (FCN). The two structures in the network can not only use the advantages of the FCN for extracting signal details but also use the characteristics of LSTM for conveying and expressing the long time-series information effectively. In this paper, a time-series data enhancement combination process is proposed for the actual poor microseismic data. A hybrid FCN-LSTM network structure was built, the optimal network parameters were obtained by experiments, and finally a reasonable microseismic data classifier was obtained.

Development of methane leakage telemetry system based on tunable diode laser absorption spectroscopy

A methane telemetry system based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) is proposed for the long-range, high-precision, and real-time measurement of methane concentration in coal mine safety production. The output wavelength of the tunable semiconductor laser is controlled to scan at 1654nm (6045.94cm−1) of the methane absorption spectrum. The harmonic signal is obtained by digital phase locking technique, and the effect of light intensity variation on the system measurement results is eliminated by 2f/1f signal processing technique. Through calibration experiment and measurement error analysis, the measurement error of the system is less than 10%, which proves that the device has the advantages of high accuracy.

Spatial and temporal convergence of provincial coal mine safety accidents and production and their influencing factors: Data from 23 coal-producing provinces in China (2005–2021)

As a high-risk industry, coal mine safety accidents can create significant loss of life and property to the nation and its people. In this work, a nonlinear time-varying factor model was adopted to investigate the spatial and temporal variation rule of coal mine safety accidents and coal production in 23 provinces of China from 2005 to 2021. The driving factors of coal mine safety accidents in 2005, 2010, 2015 and 2020 were analyzed using the geographical detector method. We further obtained the explanatory power of the primary factors and the change process of interaction. The findings showed that there are convergence clubs for both the number of coal mine safety accidents and coal production in the Chinese provinces. However, the geographical distribution of the convergence clubs varied. The geographical detector results indicated that coal mine safety accidents are affect by a combination of factors. The explanatory power of each factor for coal mine safety accidents changed over time. Notably, the explanatory power of coal production for coal mine safety accidents decreased. Industry structure, salary, security inputs, coal consumption and gross domestic product (GDP) played a significant role. The lever of impact of each factor on coal mine safety accidents was enhanced after interaction. The relationship between the factors entailed nonlinear enhanced interaction. The research findings not only contribute to a greater understanding of the macroscopic patterns of accident occurrence but also increase the awareness of the government and enterprises regarding the driving factors of coal mine safety accidents. Furthermore, such research holds crucial significance for precise prevention and control of coal mine safety accidents.

Research on Gas Flow in Vertical Fissure Field of Coal Mine Goaf

The gas in the goaf of a coal mine is difficult to extract compared to the gas in the roadway. Studying the flow pattern of gas in the goaf fracture field is of great significance for optimizing gas extraction measures and ensuring coal mine production safety. Taking a coal mining face in Shaanxi Province, China as the research object, a mathematical model of gas flow was constructed. Through finite element numerical simulation, the pressure and velocity distribution of gas in the goaf fracture field were obtained, and the influence of vertical fracture field on gas flow was analyzed. The research results provide a theoretical basis for coal mine gas control.

Research and Simulation of Kinematics and Dynamics of Tracked Support Equipment Based on Multi-Body Dynamics

Aiming at addressing the problems of low production efficiency and low safety factors in coal mines, this study designed a new type of support equipment and verified its theoretical reliability through the analysis of driving theory. The analysis was carried out through kinematics and dynamics, the position coordinates of the prototype at different times were analyzed using the RPY angles, and the spatial coordinate system of the prototype was established. Then, the position coordinates at different times could be solved by establishing the plane kinematics equations of the prototype. A 14-degree-of-freedom dynamic system model was established to reflect the longitudinal dynamic characteristics of the traveling mechanism of the prototype, and the differential equations of the traveling mechanism were established via the Lagrange dynamic equation method. Finally, the dynamic stability of the prototype under different working conditions was studied by using multi-body dynamic simulation technology. The research results show that the prototype meets the design requirements, has good reliability, realizes the mechanization, automation and high-efficiency production of coal mines, and realizes safe underground production. The research results provide effective solutions for ensuring the sustainable development of coal resources and the safe production of coal mines.

Characteristics of an underground stope channel supplied by atmospheric precipitation and its water disaster prevention in the karst mining areas of Guizhou

Atmospheric precipitation floods mining areas, which seriously affects the safe production of coal mines. However, research on the mechanism underlying precipitation supplying coal mines, particularly in karst landform areas, remains far from sufficient. Based on the collection of a large amount of geological and hydrogeological mining data and some data related to mine atmospheric precipitation and mine water inflow, the channels of atmospheric precipitation supplying mines in the main coal-producing areas of Guizhou, China, are systematically analysed and studied. They are divided into weathering zone fractures, mining fractures, water diversion faults, water diversion collapse columns and karst channels. Recharge channels have the characteristics of surface infiltration, pipeline flow and layered recharge, as well as self-healing after being filled by surface loess and other materials. The supply of atmospheric precipitation to the coal mine stope is seasonal. The mine water inflow in the rainy season is 1.2 ~ 12 times that in the dry season, with an average of 1.9 times. The supply has hysteresis. The lag time of surface infiltration, pipeline flow and layered flow is 2 ~ 4 days, within 24 h and more than 2 days, respectively. The recharge is affected by the burial depth of the coal seam and the characteristics of the combined upper roof slate. Among the mines affected by atmospheric precipitation and water disasters, some mines have carried out research on the comprehensive treatment of water disasters, implemented supplementary exploration projects such as surface hydrogeological drilling and geophysical exploration, or carried out hydrochemical research. Some mines have adopted water prevention and control projects, such as blocking ground water diversion cracks, constructing water diversion projects, adjusting the mining time of the working face, transforming the drainage system and improving the drainage capacity, to ensure the safe production of mines. This research achievement may provide a theoretical basis and practical experience for the prevention and control of atmospheric precipitation infiltration in coal mines in karst areas.

Prediction of the Water Inrush Risk from an Overlying Separation Layer in the Thick Overburden of a Thick Coal Seam

With the expansion of coal mining westward in China, water inrush from seam roofs has become a prominent safety problem during mining. The roof rock of the coal seam in the Shilawusu coal mine has the characteristics of a double-layer structure, and the overlying separation space formed in the mining process of the coal seam poses a risk of water inrush. To ensure the safety of coal mine production, considering the geological and hydrogeological data of the mining area, the core recovery rate, lithologic assemblage index, key aquifer thickness, hydrostatic head and lithologic structure index of the Zhidan Formation are selected as evaluation indexes. The index weights are calculated based on the attribute hierarchical model and coefficient of variation methods, and subjective and objective preference coefficients are introduced to determine the ranking of comprehensive indexes. The catastrophe progression method is improved, and a zoning prediction model for water inrush risk is established by the improved catastrophe progression method. The results show that only a tiny part of the mining area is in danger, and most areas are in the safe and transition zones. The model realizes the prediction of the risk of water inrush from the overlying separation layer in the study area and provides a theoretical basis for the prevention and control of water inrush from the overlying separation layer in coal mining.

A dynamic model of coalbed methane emission from boreholes in front of excavation working face: numerical model and its application.

China's current energy consumption is primarily fueled by coal, increasing coal mining with growing energy demand. Coal and gas outburst accidents are common problems in coal mining, and prediction methods are fundamental for preventing such accidents. The gas emission characteristics of boreholes are a combination of comprehensive coal properties and coal seam gas occurrence status; thus, the accurate prediction of gas emissions from boreholes is crucial for preventing such hazards. This paper presents a method for measuring the gas flow rate in continuous boreholes, which is used to predict outburst danger in front of the working face. The model was compared with field measurement data and found suitable for research. The effects of different initial gas pressures, different borehole radius, and different burial depths on gas emissions from boreholes were studied. The results showed that (1) initial gas pressure is the main influencing factor of gas gushing. The amount of gas emission during drilling and the attenuation of gas pressure are more sensitive to pressure. An increase in gas pressure considerably increases the amount of gas gushing out of drilling holes. (2) The increase in the drilling radius increases the generation of coal cuttings, the area of the drilling hole wall, and the degree of damage to the drilling hole wall. Consequently, the amount of gas gushing out of the drilling hole increases. (3) In situ stress occurs mainly because of the increase in gas pressure with an increase in burial depth and the increase in gas desorption caused by the increase in damage to the borehole wall. This study provides a new outburst prediction method, which involves identifying outburst hazards through the gas gushing out of the borehole. The results are expected to aid the control of underground coal and gas outbursts and ensure the safe production of coal mines.

How efficient coal mine methane control can benefit carbon-neutral target: Evidence from China

Coal is expected to remain the primary energy source in China for the foreseeable future. Utilizing the methane released during the mining process through effective coal mine methane (CMM) control technologies can provide triple benefits in terms of safety, energy, and the environment, thus contributing to carbon neutrality goals. However, few studies evaluated the status and benefits of CMM control. In this study, we quantify emissions, statistical extraction, and utilization of CMM to evaluate the current status of CMM control in China. Gas accidents, avoided coal consumption, greenhouse gas (GHG) emission reductions, and carbon trading revenues were used as indicators to assess the contribution of CMM controls to China's carbon neutrality goals. The results show that a total amount of 22.86 Tg methane was generated in 2020, of which 7.26 Tg was extracted, and out of that extracted amount, 5.46 Tg of methane was effectively utilized. Since 2005, CMM control has effectively ensured the safe production of coal mines, and the CMM utilized can replace 53.21 million tons of standard coal consumption and reduce GHG emissions by 958.55 TgCO2e. Furthermore, if methane were strategically included in carbon trading markets, it could generate 52.26 billion CNY in revenue. This research provides valuable scientific guidance for CMM control, CBM development project benefit assessment, and policymaking in China.

A finite element numerical simulation analysis of mine direct current method’s advanced detection under varied field sources

Ensuring the safety of coal mine production requires accurate forecasting of coal road heading faces in advance. Because of its high resistance to electromagnetic interference, the mine direct current (DC) method has been widely utilized in the advanced detection and prediction of coal mines. The layout of the field source significantly influences the detection outcomes obtained through this method. In this study, a variety of full-space three-dimensional geoelectric models were established based on the fundamental principle of DC resistivity, and the response features of geological anomalies located in various positions in front of a roadway were studied under different field source conditions using finite element numerical simulation. The electrical response characteristics were analyzed with the electrodes positioned in different directions and two-point to seven-point current sources located on the floor and side of the roadway, respectively. The electrical response of the geological anomalies was characterized with varying positions of the multi-point current source in the roadway and the pole distance of the power supply electrode. Furthermore, the electrical response characteristics of the mine DC method in advanced detection were compared for geological anomalies placed differently across the entire space. The results indicate that the response effect of the geological anomaly in front of the roadway is greater when the field source is placed on the shorter side of the roadway cross-section, with the number of field sources showing a positive correlation with the product of the pole distance and low-resistance amplitude. In advanced detection by DC method, the existence of geological anomalies on the side will affect the recognition of anomalies in front of the roadway.

Coal Mine Rock Burst and Coal and Gas Outburst Perception Alarm Method Based on Visible Light Imagery

To solve the current reliance of coal mine rock burst and coal and gas outburst detection on mainly manual methods and the problem wherein it is still difficult to ensure disaster warning required to meet the needs of coal mine safety production, a coal mine rock burst and coal and gas outburst perception alarm method based on visible light imagery is proposed. Real-time video images were collected by color cameras in key areas of underground coal mines; the occurrence of disasters was determined by noting when the black area of a video image increases greatly, when the average brightness is less than the set brightness threshold, and when the moving speed of an object resulting in a large increase in the black area is greater than the set speed threshold (V > 13 m/s); methane concentration characteristics were used to distinguish rock burst and coal and gas outburst accidents, and an alarm was created. A set of disaster-characteristic simulation devices was designed. A Φ315 mm white PVC pipe was used to simulate the roadway and background equipment; Φ10 mm rubber balls were used to replace crushed coal rocks; a color camera with a 2.8 mm focal length, 30 FPS, and 110° field angle was used for image acquisition. The results of our study show that the recognition effect is good, which verifies the feasibility and effectiveness of the method.

Experimental study of improved cement silicate grouting material for broken surrounding rock

The broken surrounding rock seriously affects the safety production of coal mines. This paper design the orthogonal experiment of fly ash-cement-silicate grouting material and the activation experiment of fly ash to obtain the proportion of the cement silicate grouting material and the activation conditions of fly ash to meet the requirements for supporting the broken surrounding rock. The influence law of water-content ratio, fly ash content, silicate concentration and silicate content on the setting time and strength of cement silicate grouting materials are studied, the influence law of activator content and activation time on the activation performance of fly ash are compared and analyzed. The study of this paper elucidates the hydration reaction mechanism of cement silicate grouting material and the activation mechanism of fly ash. It solves the problems of unreasonable grouting material proportion, unclear activation conditions of fly ash, and difficulty in supporting the broken surrounding rock. The influence law of activator content and activation time on the network structure of grouting materials are obtained. The proportion of grouting materials meeting the requirements is the water-cement ratio of 0.8, fly ash content of 30%, silicate concentration of 40 Be’ and silicate content of 25%, the most optimum activation conditions are that activation time is 2h and activator content is 3%. The influence of cement silicate grouting material on the support effect of broken surrounding rock is obtained, the displacement of the roadway's sides and roadway's roof using grouting materials is 40% and 36% less than that of roadway's sides and roadway's roof without grouting material. The significance of this paper is to deeply analyze the effects of water-cement ratio, fly ash content, silicate concentration and silicate content on the setting time and strength of cement silicate grouting materials and obtain the effects of activator content and activation time on the activation effect of fly ash. Applying the proportion of the cement silicate grouting material and the activation conditions of fly ash in engineering practice has achieved good results, which can increase the stability of broken surrounding rock and effectively control surrounding rock deformation.

Fault Diagnosis of Rolling Bearings in Primary Mine Fans under Sample Imbalance Conditions.

Rolling bearings are crucial parts of primary mine fans. In order to guarantee the safety of coal mine production, primary mine fans commonly work during regular operation and are immediately shut down for repair in case of failure. This causes the sample imbalance phenomenon in fault diagnosis (FD), i.e., there are many more normal state samples than faulty ones, seriously affecting the precision of FD. Therefore, the current study presents an FD approach for the rolling bearings of primary mine fans under sample imbalance conditions via symmetrized dot pattern (SDP) images, denoising diffusion probabilistic models (DDPMs), the image generation method, and a convolutional neural network (CNN). First, the 1D bearing vibration signal was transformed into an SDP image with significant characteristics, and the DDPM was employed to create a generated image with similar feature distributions to the real fault image of the minority class. Then, the generated images were supplemented into the imbalanced dataset for data augmentation to balance the minority class samples with the majority ones. Finally, a CNN was utilized as a fault diagnosis model to identify and detect the rolling bearings' operating conditions. In order to assess the efficiency of the presented method, experiments were performed using the regular rolling bearing dataset and primary mine fan rolling bearing data under actual operating situations. The experimental results indicate that the presented method can more efficiently fit the real image samples' feature distribution and generate image samples with higher similarity than other commonly used methods. Moreover, the diagnostic precision of the FD model can be effectively enhanced by gradually expanding and enhancing the unbalanced dataset.

Evaluation Model of Hard Limestone Reformation and Strength Weakening Based on Acidic Effect

The typical thick-hard limestone roof with high failure pressure and easy fracture closure under in situ stress is extremely prone to induce disasters, which seriously threatens the safe production of coal mines. The modification of carbonate minerals by acidic effects can effectively realize the weakening control of hard limestone strata. In this study, a multi-factor orthogonal experiment was designed for limestone acidification reactions, and the evaluation model for the reformation and strength weakening of hard limestone based on the acidic effect was established accordingly. The results showed that there is an order in the influence of various factors on the reaction parameters and strength indices of acidified limestone, and the improvement of rock properties by the level difference of acid concentration is significantly better than that of acid type and acidification time. Through numerical analysis, the evaluation model of limestone reformation and strength weakening considering the acid reaction parameters is given. The reliability of the model passed the credibility test and experimental verification, which can effectively reflect the strength response characteristics of acidified limestone. The simulated annealing (SA) algorithm is introduced to derive the optimal acidification system suitable for limestone weakening. Combined with the model, the control mechanism of the acidic effect on hard limestone strata was analyzed. The acidic effect can not only induce the rapid generation and expansion of micro-cracks at mineral-containing crystal defects, but also make the cracks remain relatively open under in situ stress due to the differential interaction on mineral components, which is conducive to the bearing capacity reduction and structural damage of limestone rock mass. The research results provide theoretical guidance for the acidification control of hard limestone strata in underground mines.

Three-Dimensional Pore Structure Characterization of Bituminous Coal and Its Relationship with Adsorption Capacity.

Bituminous coal reservoirs exhibit pronounced heterogeneity, which significantly impedes the production capacity of coalbed methane. Therefore, obtaining a thorough comprehension of the pore characteristics of bituminous coal reservoirs is essential for understanding the dynamic interaction between gas and coal, as well as ensuring the safety and efficiency of coal mine production. In this study, we conducted a comprehensive analysis of the pore structure and surface roughness of six bituminous coal samples (1.19% < Ro,max < 2.55%) using various atomic force microscopy (AFM) techniques. Firstly, we compared the microscopic morphology obtained through low-pressure nitrogen gas adsorption (LP-N2-GA) and AFM. It was observed that LP-N2-GA provides a comprehensive depiction of various pore structures, whereas AFM only allows the observation of V-shaped and wedge-shaped pores. Subsequently, the pore structure analysis of the coal samples was performed using Threshold and Chen's algorithms at ×200 and ×4000 magnifications. Our findings indicate that Chen's algorithm enables the observation of a greater number of pores compared to the Threshold algorithm. Moreover, the porosity obtained through the 3D algorithm is more accurate and closely aligns with the results from LP-N2-GA analysis. Regarding the effect of magnification, it was found that ×4000 magnification yielded a higher number of pores compared to ×200 magnification. The roughness values (Rq and Ra) obtained at ×200 magnification were 5-14 times greater than those at ×4000 magnification. Interestingly, despite the differences in magnification, the difference in porosity between ×200 and ×4000 was not significant. Furthermore, when comparing the results with the HP-CH4-GA experiment, it was observed that an increase in Ra and Rq values positively influenced gas adsorption, while an increase in Rsk and Rku values had an unfavorable effect on gas adsorption. This suggests that surface roughness plays a crucial role in gas adsorption behavior. Overall, the findings highlight the significant influence of different methods on the evaluation of pore structure. The 3D algorithm and ×4000 magnification provide a more accurate description of the pore structure. Additionally, the variation in 3D surface roughness was found to be related to coal rank and had a notable effect on gas adsorption.

Effects of water immersion and pre-oxidation on re-ignition characteristics of non-caking coal

Coal spontaneous combustion (CSC) in waterlogged goafs has become an essential threat to coal mine safety production, so it is necessary to comprehensively and deeply evaluate the re-ignition characteristics of residual coal after water immersion and pre-oxidation. The re-ignition process of non-caking coal under the influence of water immersion and pre-oxidation was tested using a temperature-programmed test system (TPTS), and the spontaneous combustion characteristic parameters and limit characteristic parameters of low-temperature oxidation were calculated. The results show that the spontaneous combustion characteristic parameters such as CO production rate, oxygen consumption rate, and heat release intensity positively correlate with temperature. The minimum float coal thickness and lower limit oxygen concentration show a trend of increasing and then decreasing with the temperature increase, while the maximal air leakage intensity is the opposite. In addition, the expansion of pores and cracks caused by water immersion and pre-oxidation processes and the increase of unstable functional groups promote the oxygen consumption and heat generation of immersed and oxidized coal, which reduces the characteristic temperature, and activation energy, and limit characteristic parameters. Meanwhile, water immersion and pre-oxidation can synergistically accelerate the low-temperature oxidation process of non-caking coal, which significantly increases the CSC risk of coal O140I30 and coal O90I30. The results enrich the research on the characteristics of water immersed and oxidation coals re-ignition, which may be applied to prevent CSC in the future.

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.

Risk assessment of coal mine gas explosion based on cloud integrated similarity and fuzzy DEMATEL

The risk of coal mine gas explosion seriously threatens the continuous safe production of coal mines, which in turn affects the national energy security, so it is important to prevent and control the coal mine gas risk. Current risk assessment methods are difficult to fully express the uncertainty in the assessment process, and calculating index weights is easy to deviate from reality. This study introduces Decision-making Trial and Evaluation Laboratory (DEMATEL) as well as the cloud model, and proposes a new coal mine gas explosion risk assessment model based on cloud integrated similarity and fuzzy DEMATEL. The model fully expresses the uncertainty in the whole risk assessment process and makes the index weights assignment more reasonable. It also combines the calculation of cloud integrated similarity to more accurately determine the risk level based on the advantage that the cloud model can visually display the risk status of the assessment object. An example study was conducted on a mine of a large state-owned coal mine enterprise in Shaanxi Province, China. The results show that the method helps coal mine enterprises to accurately assess gas explosion risks, identify weak links in risk prevention and control, and provide a powerful means for continuous improvement of risk management level.

A study on the simulation of psychological and behavioral dynamics in the unsafe state of coal mine workers

The coal mine production safety hazards are large, and the situation is difficult, and coal mine workers are affected psychologically, producing unsafe psychological states and triggering unsafe behavior. This paper firstly studies the interactive influence process of the unsafe psychological state of coal mine workers and reveals the emergence process of unsafe psychology and behavior of coal mine workers. According to the characteristics of qualitative simulation of safety behavior, safety psychology and unsafe state of coal mine personnel, 23 simulation schemes are designed, and simulation analysis is carried out using QSIM simulation software platform. According to the simulation results of 23 schemes, the dynamic emergence process of safety behavior, safety psychology, and unsafe state of coal mine workers was sorted out from the aspects of different states and the intensity of different management measures, and the law of the effect of coal mine workers' safety psychology on safety behavior and safety state was obtained , revealing the interactive influence of coal mine workers' psychology on the unsafe state and the internal evolution mechanism of the emergent process. It is of great theoretical and practical significance for coal mine safety management to study the interaction of hazardous psychological states of coal mine workers and the dynamic generation mechanism of the emergence process of unsafe behaviors.

Forecasting law enforcement frequency of internet+ coal mine safety supervision

PurposeCoal is the basic energy and essential resource in China, which is crucial to the economic lifeline and energy security of the country. Coal mining has been ever exposed to potential safety risks owing to the complex geologic environment. Effective safety supervision is a vital guarantee for safe production in coal mines. This paper aims to explore the impacts of the internet+ coal mine safety supervision (CMSS) mode that is being emerged in China.Design/methodology/approachIn this study, the key factors influencing CMSS are identified by social network analysis. They are used to develop a multiple linear regression model of law enforcement frequency for conventional CMSS mode, which is then modified by an analytical hierarchy process to predict the law enforcement frequency of internet+ CMSS mode.FindingsThe regression model demonstrated high accuracy and reliability in predicting law enforcement frequency. Comparative analysis revealed that the law enforcement frequency in the internet+ mode was approximately 40% lower than the conventional mode. This reduction suggests a potential improvement in cost-efficiency, and the difference is expected to become even more significant with an increase in law enforcement frequency.Originality/valueTo the best of the authors’ knowledge, this is one of the few available pieces of research which explore the cost-efficiency of CMSS by forecasting law enforcement frequency. The study results provide a theoretical basis for promoting the internet+ CMSS mode to realize the healthy and sustainable development of the coal mining industry.