Abstract
BACKGROUND:
Most studies have focused on the establishment and application of the risk precontrol management system for safety in coal mines and have seldom considered the evaluation of the system operation effect.
OBJECTIVE:
This study aimed to evaluate the operation effect of risk precontrol management system of safety in coal mines and propose policy suggestions to improve the risk precontrol management level of safety.
METHODS:
This study applied the Objective and Subjective Weighting Method (OSWM) combined with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) to conduct evaluation and empirical research on the operation effect of the risk precontrol management system of safety in coal mines.
RESULTS:
First, the evaluation index system is mainly composed of six first-level indicators and 30 subordinate secondary indicators. Second, the OSWM combined with TOPSIS is an effective method for operation effect evaluation, which yields accurate and undistorted evaluation results. Third, the calculation reference value of the operation effect in the Gengcun coal mine is 57.34, and its corresponding effect level is level III, which is basically effective. Moreover, the calculation reference values of production equipment management (P4) and inspection, audit and review (P6) are the lowest, while the calculation reference values of risk precontrol management (P1) and auxiliary management (P5) reach the critical value corresponding to effect level I, which indicates a good operation effect.
CONCLUSIONS:
Corresponding policy suggestions to improve the risk precontrol management level in the Gengcun coal mine are proposed based on the above evaluation results.
Introduction
The coal mining industry is a typical industry with three highs, namely, a high labour intensity, high employment risk, and high accident rate [1–3]. Therefore, the problem of coal mine safety is a focus of Chinese political circles, and it remains an important topic worthy of study in academic circles [4]. In recent years, risk-based governance has rapidly developed in the main coal-producing countries worldwide, and it has gradually replaced the prescriptive mode of coal mine safety governance. Compared to traditional prescriptive coal mine safety governance, risk-based governance is more desirable and preferable, and it is the development trend of coal mine safety management in the future [5], which has also attracted much attention from the Chinese government and coal mine enterprises and has been widely investigated. On July 12, 2011, the former State Administration of Work Safety issued the risk precontrol management system of safety in coal mines specification (AQ/T 1093-2011), which was implemented on December 1, 2011, marking the beginning of the era of the risk precontrol management system of safety in Chinese coal mines [5, 6]. AQ/T 1093-2011 has been rapidly promoted across the coal industry, which also marks the transformation of the Chinese coal mine safety management mode from traditional experiential management and institutional management to higher-level risk precontrol management.
The implementation of the risk precontrol management system for safety in coal mines has reduced the number of coal mine accidents and casualties. However, the control of coal mine accidents has not achieved the expected effect due to the existing unscientific or unsystematic problems in the implementation of the system. Compared to the main coal-producing countries globally, the casualty and death rates per million tons in Chinese coal mines remain very high [8]. Therefore, it is of major theoretical and practical importance to conduct evaluation and empirical research on the operation effect of the risk precontrol management system of safety in coal mines, resolve the current problems in the operating process of the risk precontrol system, and effectively improve the safety management level of coal mine enterprises.
Literature review
The foreign coal mine safety management theory has experienced a transformation process in terms of machine-, human- and management-centred aspects. At present, both theoretical and empirical studies on safety management are relatively mature, mainly focusing on the development status and effectiveness evaluation of the safety management system [9]. On the basis of the development of the safety management system theory, various safety management systems and methods have successively emerged from the internationally well-known Occupational Health and Safety Assessment Series (OHSAS) management system to the Health, Safety and Environment (HSE) management system in the petrochemical industry, from the comprehensive management system in the United States to the NOSA safety management system in South Africa [10, 11].
With the development of the theoretical system of coal mine safety management, foreign scholars focused on the effect of risk precontrol management, mainly reflected in the impact on the accident rate [12], the degree of injuries in the workplace [13–15], and the production efficiency of coal mining enterprises [16, 17], Robson evaluated the effectiveness of the intervention of the occupational health and safety management system (OHSMS) on enterprise safety management [12]. Asadzadeh comprehensively analysed and assessed HSE and health, safety, environment and ergonomics (HSEE) factors through a fuzzy cognitive map (FCM) [12]. Haas and Yorio constructed and evaluated OHSMS performance indicators [16]. Stolzer et al. evaluated the effectiveness of the safety management system based on the evolution law of big data [17].
In recent years, domestic scholars have also focused on research in the field of risk precontrol management of safety in coal mines from different perspectives, such as Li et al., Zhang and Yan, Meng et al., He et al., Yang, and Liu et al. who studied the relevant theories and methods of risk precontrol management of safety in coal mines [18–23], and Chen, Hao and Song, Hao, Meng and Li, Li, and Qiao and Xie, who studied the construction and implementation of the risk precontrol management system of safety in coal mines [6, 24–27]. With the development of the theoretical system of coal mine safety management, Chinese scholars have studied the disadvantages of the current risk precontrol management system of safety in coal mines and relevant improvement measures from different perspectives, e.g., Yang and Gao and Liu examined how to improve the risk precontrol effect of safety in coal mines from the perspective of institutions. In addition to the above viewpoints [28, 29], Fu and Zhang pointed out that the content of risk classification control is to identify hazards, assess hazards, and control risks [30]. Fu et al. further determined the relationship between hazards and accidents and found that hazards are the root cause of accidents [31]. Wang proposed the organic integration of the risk precontrol management system and post-standard operation process in coal mines and reported that the post-standard operation process is an effective measure to realize risk control [32]. Wang and Wu developed a new method of system safety management based on the best safety-related information, which attains a high correctness and effectiveness in theory [33]. In addition, a few scholars have investigated the operation effect of the risk precontrol management system of safety in coal mines in recent years, e.g., Jiang and Li proposed an evaluation model of the risk precontrol management system of safety in coal mines based on fuzzy data envelopment analysis (DEA) [34]. Sun conducted an empirical study on the operation effect of a risk precontrol system in the Shenhua Group and suggested targeted improvement countermeasures [35, 36].
In summary, relevant experts in China and abroad have performed much research and examination of the risk precontrol management system of safety in coal mines, and foreign research has transitioned from the stage of establishing risk management systems to the stage of improving and upgrading risk management systems, but most Chinese studies focus on the stage of system establishment and application and seldom involve the evaluation of the system operation effect and corresponding empirical research. Therefore, based on the above research background and status, this paper selects the operation effect evaluation process of the risk precontrol management system of safety in coal mines as the research object, applies the Objective and Subjective Weighting Method (OSWM) combined with the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) to conduct evaluation and empirical research on the operation effect of the risk precontrol management system of safety in coal mines and proposes policy suggestions to improve the risk precontrol management level of safety in coal mines based on the obtained evaluation results.
Construction of the evaluation index system
The establishment of an evaluation index system according to the actual conditions of coal mining enterprises is the premise and basis of the evaluation of risk precontrol management systems of safety in coal mines [37]. In this study, the steps of constructing the evaluation index system of the risk precontrol management system are shown in Fig. 1.

Steps of constructing the evaluation index system.
First, this paper analyzes 177 serious accidents and extraordinarily serious accidents in coal mines from 2014 to 2018, as listed in Tables 1 2, traces the causes of these accidents, and extracts the reasons influencing the effectiveness of the risk precontrol management system of safety in coal mines. The data are mainly obtained from the National Coal Mine Safety Administration, China Coal Network, and Coal Mine Safety Net. Second, based on the literature and theoretical analysis, this paper adopts Citespace combined with pivot tables in Excel to establish the PivotChart method and then extracts 33 influencing factors of the implementation of the risk precontrol management system, as summarized in Table 3.
Number of serious and extraordinarily serious accidents and death toll from 2014–2018
Number of serious and extraordinarily serious accidents and death toll from 2014–2018
Type of serious and extraordinarily serious accidents and their numbers and death toll from 2014–2018
Literature distribution of the influencing factors of the implementation of the risk precontrol management system
Based on the above typical case analysis and literature research and referring to the risk precontrol management system of safety in coal mines specification (AQ/T 1093-2011), the evaluation indexes of the risk precontrol management system are summarized into six aspects: risk precontrol management, safety assurance management, personnel safety management, production equipment management, auxiliary management, and inspection, audit and review. Therefore, the evaluation index system is preliminarily constructed, including 6 first-class indicators and 33 second-class indicators.
Screening of the evaluation indexes
The preliminary evaluation indexes are modified by designing and analysing questionnaires combined with the correlation coefficient analysis method. Finally, the above six first-class indicators and 30 second-class indicators are screened as the evaluation indexes of the risk precontrol management system of safety in coal mines, as listed in Table 4.
Evaluation indexes of the risk precontrol management system of safety in coal mines
Evaluation indexes of the risk precontrol management system of safety in coal mines
Evaluation method
The commonly applied weighting methods mainly include the subjective weighting method, which is based on subjective experiential knowledge, and the objective weighting method, which is based on objective data using mathematical statistics. These two methods have their own advantages and disadvantages. First, the subjective weighting method computes qualitative indicators to obtain weights mainly based on the knowledge and experience of experts or scholars, which suffers a certain subjectivity. Moreover, the limitations of the educational background and research field of the experts may generate certain differences in the evaluation results. Second, the objective weighting method relies on mathematical statistics to calculate the index weight based on certain objective data, which objectively reflects the reality of the indexes but does not reflect the attributes among the indicators and may be inconsistent with the reality. Therefore, this paper applies the analytic hierarchy process (AHP) and entropy methods to obtain the independent weights and then comprehensively implements the OSWM to obtain the combined weights [38–40].
A coal mine system is a dynamic and complex system composed of multiple factors in time and space, and its safety status is influenced by many factors. TOPSIS ranks the relative advantages and disadvantages of the existing multiple indexes. Its core idea is to calculate the distance between the evaluation object and the optimal and worst solutions according to the solution steps based on the obtained indexes, and it adopts the absolute distance to measure the advantages and disadvantages of various schemes [41]. Therefore, after applying the OSWM to obtain the combined weights, TOPSIS is implemented to determine the closeness degree on the basis of the ideal solution and Euclidean distance. Furthermore, the comprehensive evaluation score of the system operation effect is calculated by multiplying the closeness degree and combined weight. The combination of OSWM and TOPSIS gives full play to the advantages of these two methods, ensures accurate and undistorted evaluation results and accurately and logically achieves the evaluation of the system operation effect.
Empirical analysis
It has been seven years since the Gengcun coal mine of the Yimei Group in Henan Province started to construct and implement the risk precontrol management system of safety. Therefore, on the basis of the above evaluation index system, this paper chooses the Gengcun coal mine as an example to conduct an empirical study on the operational effect of the risk precontrol management system of safety by comprehensively applying the OSWM and TOPSIS and proposes policy suggestions to enhance the risk precontrol management level according to the evaluation results.
Determination of the subjective weights using AHP
With the use of the expert scoring method, 25 highly experienced experts were selected, including 8 professors engaged in coal mine safety management research at universities for many years, and the rest consisted of middle-level leaders or above of the management, technology and production departments of coal mine enterprises. Furthermore, the statistics, analysis, and summary of the expert opinions were anonymous obtained, and the judgement matrix was then constructed by comparing the indexes in pairs according to the expert experiences. MATLAB was adopted to determine the judgement matrix to obtain the weights at all levels of the indicators, whereby the weights of the first-level indicators were as follows: the weight of P1 is 0.3794, that of P2 is 0.1605, that of P3 is 0.2488, that of P4 is 0.1024, that of P5 is 0.0435, and that of P6 is 0.0655. The weights of the second-level indicators are listed in Table 5.
Weights of the evaluation index system calculated by the AHP, entropy method and OSWM
Weights of the evaluation index system calculated by the AHP, entropy method and OSWM
The entropy method facilitates an objective and fair comprehensive system evaluation as an objective weighting method. This paper selects the corresponding data of the Gengcun coal mine from 2014 to 2018 according to AQ/T 1093-2011 and the actual situation to evaluate the scores of each indicator using the entropy method. The weights at all levels of the indicators are determined. Specifically, the weights of the first-level indicators are as follows: the weight of P1 is 0.1611, that of P2 is 0.1655, that of P3 is 0.1341, that of P4 is 0.2436, that of P5 is 0.2015, and that of P6 is 0.0943. In addition, the weights of the second-level indicators are summarized in Table 5.
Determination of the combined weight using OSWM
After obtaining the independent weights by the AHP and entropy methods, the combined weights (Equation 1) are obtained by using the OSWM. Specifically, the weights of the first-level indicators are as follows: the weight of P1 is 0.1720, that of P2 is 0.1680, that of P3 is 0.1860, that of P4 is 0.1840, that of P5 is 0.1180, and that of P6 is 0.1720. Moreover, the weights of the second-level indicators are provided in Table 5. The combined use of the AHP and entropy methods, i.e., applying the OSWM to obtain the final weights of the indicators, not only makes use of the rich knowledge and experience of experts but also integrates the objective reality of actual data and overcomes the shortcomings of a single method to a certain extent.
where:
W
i
* is the combined weight of the ith index calculated by the OSWM, W
i
is the weight calculated by the AHP,
Based on the above literature research, most scholars have focused on the classification of the coal mine safety status, which is divided into five levels, namely, level I (effective), level II (relatively effective), level III (basically effective), level IV (basically ineffective), and level V (ineffective). The critical value of each level is defined according to the relevant provisions of the coal mine industry. With the Gengcun coal mine as an example, the reference value of the system operation state under the second-class indexes is obtained according to the actual conditions of the mine, and the reference value data (using the percentage system) are adopted as standards to evaluate the coal mine safety status, as listed in Table 6.
Critical value division of each effective level in the Gengcun coal mine
Critical value division of each effective level in the Gengcun coal mine
The initial judgement matrix (Q1) is established according to Table 6. In Table 6, each row contains the second-class indexes of P11, P12, P13, P14, and P15, the first four columns are the quantitative values of the operating state of the Gengcun coal mine, which are obtained through expert scoring according to the actual situation of the Gengcun coal mine, and the fifth column provides the reference value. Then, the initial judgement matrix (Q1) is first standardized and multiplied by the above corresponding combined weights to obtain the weighting matrix (
Similarly, the closeness degrees of the remaining 25 second-class indicators, which are subordinate to the other five first-class indicators, are obtained.
Therefore, the closeness degree matrix (E) is constructed based on the above calculation of the closeness degrees of the various indicators. Furthermore, the weight matrix (α) is established based on the above obtained weights of the first-level indicators using the OSWM, namely, 0.172, 0.168, 0.186, 0.184, 0.118, and 0.172. Finally, the standardized and quantitative values of the operation effect level of the risk precontrol management system (F) are computed.
The first four columns of F contain the standardized and quantitative values of the operation effect level of the risk precontrol management system, and the last column provides the reference value of the operation effect level of the coal mine, which are converted into percentages to grade the values according to I > 62.4, II > 61.87, III > 56.97, IV > 45.88, and V≤45.88, while the reference value is 57.34. The operation effect level of the Gengcun coal mine is at level III, which is basically effective and is consistent with the actual environment of the coal mine. This indicates that the coal mine can continue to implement the risk precontrol management system according to the actual situation and should strengthen any remedial measures targeting existing defects in a timely manner. Moreover, after the closeness degree matrix (E) is converted into the percentage matrix, the first four columns contain the critical values of each operation effect level, and the fifth column provides the reference values of the six first-level indicators. Specifically, the reference value of risk precontrol management (P1) is 83.7, which reveals that the operation effect level of risk precontrol management (P1) is level II (relatively effective). The reference value of safety assurance management (P2) is 51.9, which indicates that the operation effect level of safety assurance management (P2) is level III (basically effective). The reference value of personnel safety management (P3) is 64.0, which demonstrates that the operation effect level of personnel safety management (P3) is level IV (basically ineffective). The reference value of production equipment management (P4) is 36.4, which shows that the operation effect level of production equipment management (P4) is level V (ineffective). The reference value of auxiliary management (P5) is 78.6, which reveals that the operation effect level of auxiliary management (P5) is level I (effective), and the reference value of inspection, audit and review (P6) is 36.8, which indicates that the operation effect level of inspection, audit and review (P6) is basically ineffective. Therefore, policy suggestions to enhance the level of risk precontrol management in the Gengcun coal mine are proposed based on the above evaluation results.
First, it is determined from the evaluation results that the calculated reference values of production equipment management (P4) and inspection, audit and review (P6) are the lowest and lower than the critical value corresponding to operation effect level V, which comprise the short list of enterprises. Therefore, the enterprise should focus on strengthening the following two aspects. The troubleshooting and maintenance processes of ventilation equipment, mining equipment, blasting equipment, ground survey equipment, fire prevention equipment, and dustproof equipment in the production system should be enhanced, and relevant equipment should be modified if necessary. Second, the aspects of the revision and improvement of inspection, audit and review should be improved, specifically: (1) the evaluation standards reflecting the performance of the risk precontrol management system in the enterprise should be revised and improved; (2) regular or irregular inspection should be conducted according to the evaluation standards, emphasizing the hazards that may cause unacceptable risks, and the inspection records must be true, accurate and traceable; (3) the causes of the nonconforming items identified during the inspection should be analysed and corrected according to the treatment procedures relevant to the nonconformity, and corresponding preventive measures should be re-audited or re-formulated to prevent recurrence; (4) system audit procedures should be properly revised and maintained, and audits of the risk precontrol management system should be regularly performed to determine whether the conformity evaluation between the audit situation and system effectively meets the enterprise’s policies and objectives; and (5) the system should be reviewed according to specified time intervals to ensure the continuous suitability, sufficiency and effectiveness of the system.
In addition, the reference value of safety assurance management (P2) is 51.9, corresponding to operation effect level IV, which should also be strengthened and enhanced from the perspective of organizational, institutional, technical, capital and safety culture guarantees. Specifically, (1) in terms of the organizational guarantee, a risk precontrol management organization should be established and improved; (2) in terms of the institutional guarantee, the management institutions related to the risk precontrol management system of safety should be developed and enhanced; (3) in terms of the technical guarantee, safety technology management and control procedures should be regularly revised and maintained to control major hazards; (4) in terms of the capital guarantee, safety investment management and control procedures should be suitably updated and maintained to provide the necessary financial support for the implementation and improvement of the risk precontrol management system; and (5) in terms of the safety culture guarantee, safety culture construction management procedures should be revised and supported to give full play to the guidance, incentive and cohesion functions of the safety culture.
Finally, the calculation reference values of risk precontrol management (P1) and auxiliary management (P5) reach the critical value corresponding to operation effect level I, which indicates a good operation effect. The coal mining enterprise can continue existing working methods and focus on tracking the operation effect of relevant indicators to ensure that the operation effect of these indicators remains suitable and stable.
Conclusion
This paper chooses the evaluation of the system operation effect as the research object. An evaluation index system is first constructed, after which the OSWM combined with TOPSIS is applied to conduct evaluation and empirical research on the operation effect of the risk precontrol management system of safety in coal mines. Moreover, corresponding policy suggestions to improve the level of risk precontrol management in coal mines are proposed based on the evaluation results. The main research results are summarized below.
First, the influencing factors of coal mine accidents are extracted and summarized by analysing 177 serious and extraordinarily serious accidents from 2014 to 2018, and these influencing factors are then integrated and screened by using questionnaire surveys and the correlation coefficient method. Six first-class indicators, including risk precontrol management (P1), safety assurance management (P2), personnel safety management (P3), production equipment management (P4), auxiliary management (P5), and inspection, audit and review (P6), and 30 subordinate second-class indicators are screened as the evaluation indicators of the risk precontrol management system of safety in coal mines.
Second, the OSWM combined with TOPSIS is an effective approach to evaluate the operation effect of the risk precontrol management system of safety in coal mines, which includes the following five steps: determination of the subjective weight using AHP, determination of the objective weight using the entropy method, determination of the combined weight using the OSWM, establishment of the TOPSIS evaluation model, and result analysis. The combination of the OSWM and TOPSIS gives full play to the advantages of these two methods, ensures accurate and undistorted evaluation results and accurately and logically achieves the evaluation of the system operation effect.
Third, this paper selects the Gengcun coal mine as an example to conduct an empirical study, and the results reveal that the calculation reference value of the operation effect of the Gengcun coal mine is 57.34, and its corresponding operation effect level is level III, which is basically effective. Moreover, the calculation reference values of production equipment management (P4) and inspection, audit and review (P6) are the lowest and lower than the critical value corresponding to operation effect level V, which comprise the short list of enterprises, and the calculation reference values of risk precontrol management (P1) and auxiliary management (P5) reach the critical value corresponding to operation effect level I, which indicates a good operation effect.
Footnotes
Acknowledgments
This work was supported by the the National Social Science Foundation of China (Grant no. 21BGL297).
Conflict of interest
The authors declare that they do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.
