| After years of efforts, a steady improvement has appeared in the field of coal mine production safety in China. But obviously, the trend of frequent accidents hasn’t been controlled fundamentally; a severe and comlex situation still exists in China’s coal mine production safety as the total number of accidents and casualties still remain large. Roof accidents endanger coal mine production safety seriously and it is worthy to study them.Currently, the research of roof accidents prevetion mainly focuses on the roof control and technology of roof support, lacking of study on the behavior. Therefore, BBS can effectively control the occurrence of roof accidents, thus improving the safety production level of enterprises. As the application of BBS in the preventing the roof accidents is relatively scarce, results obtained from analyzing roof accidents with BBS can be used as the foundation for safety training in enterprises which is one of the main measures of accidents prevention.On the basis of the study on mechanism of roof caving, from the national coal mine accidents analysis reports over the years and accidents searching system of State Adminstration of Work Safety, the basic information of the available accidents from 2005 to 2012 are analysed and studied statiscally, including accidents grade, forms of ownership, sites of the accidents and accidents causes. Several basic laws of roof accidents are obtained. Firstly, the number of ordinary roof accidents and the death toll are the largest, both taking a percentage of above 90. Secondly, the number of accidents coal mines in the villages declines sharply, but still occupies about 70% of the total number of less roof accidents. Thirdly, most of the roof accidents take place in coal working face and heading face. Fourthly, engineering of poor quality cuase the most roof accidents, followed by working under the roof without support or with failed support. Fifthly, from 2005 to 2012, in China’s 25 provinces(autonomous regions and municipalities directly under the central government) and the Xinjiang Production and Construction Corps, the number of roof accidents and the deaths are positively related and more accidents occur in south area than the north. Due to the geology, climate and safety investment, roof accidents tend to happen frequently in Sichuan, Chongqing, Guizhou, Hunan and Yunnan. Sixthly, roof accidents occur more frequently during the Spring Festival and August. More accidents occur in the daytime than at night. Also, accidents are prone to happen when shifting the duty and two hours later the shift.By comparing and contrasting the REASON cheese model, HFACS model and the behavior-based accident causation “2-4”model, it can be concluded that the last one has the clear hierarchy, high operability, specific elements, general applicability for all industries and simplicity of operation. According to the model, the dissertation study the accident causes of four levels and four types of personnel, in detail, senior management, middle and front-line management, on-site commanders and front-line workers. 5 typical roof accidents are analyzed using the behavior-based accident causation “2-4”model. Not only are all the accident causes and accident causation chain got, but also the effectiveness of the behavior-based accident causation “2-4”model in accident prevention is demonstrated.Unsafe acts of 331 roof accidents are analyzed based on the behavior-based accident causation “2-4”model, 1035 unsafe acts are obtained in total. And deep classification, analysis and study are done at the same time. The whole unsafe acts are divided into 15 categories, namely, safe operation, safety check, blasting, general unsafe acts, regulations and measures, prop recycling and roof caving, supervising and monitoring, driving, mining, labor organization, working at risk, escaping, removing hazards, supporting and instructing. The unsafe acts are put in order according to the frequency from the highest to the lowest. There are 9 types of unsafe acts occur more than 50 times, among which unsafe acts of supporting occur the most frequently which occur 190 times, accounting for 18.36% of the total number of unsafe acts. Then the rest are put in sequence as follows, unsafe acts of safety check with a frequency of 119, a percentage of 11.5, general unsafe acts, unsafe acts of regulations and measures, unsafe acts of supervising and monitoring, unsafe acts of working at risk, unsafe acts of removing hazards, unsafe acts of instructing, unsafe acts of mining. There are 18 subtypes of unsafe acts which occur more than 20 times. They accounts for 69.18% of the total number of unsafe acts. Unsafe acts of working at the site without support or with ineffective support rank the first with a frequency of 93 times, accounting for 8.99% of the total number of unsafe acts. Then the rest are put in sequence as follows, unsafe acts of supporting incorrectly, unsafe acts of failing to supervise the job, unsafe acts of failing to check the surrounding environment, unsafe acts of illegal command, unsafe acts of failing to remove the hazards timely, unsafe acts of failing to support timely, unsafe acts of violating the operating instruction, unsafe acts of failing to check the surrounding environment during work, unsafe acts of failing to take safety measures, unsafe acts of conducting inadequate safety check, unsafe acts of illegal exploitation, unsafe acts of persuading improperly, unsafe acts of failing to strengthening the support, unsafe acts of conducting or receiving inadequate safety training, unsafe acts of failing to make safety technical measures, unsafe acts of illegal blasting and unsafe acts of failing to leave the job site with evident omens of roof caving. Except for the unsafe acts of conducting or receiving inadequate safety training and failing to leave the job site with evident omens of roof caving, the rest of the16 subtypes of unsafe acts are all included in the unsafe acts which occur more than 50 times. They are the key of roof accidents prevention.The key unsafe acts and trainees of safety training are obtained via analyzing the 15 types of unsafe acts in depth. 1) For unsafe acts of safe operation, the key trainees are senior management and middle and front-line management and the key unsafe acts are failing to carry out safety training for workers and using backward wooden supports. 2) For unsafe acts of safety check, the key trainees are the front-line workers and on-site commanders and safety inspectors need more training and the key unsafe acts are failing to check the roof before work and inadequate wall tapping and roof sounding before work. 3) For unsafe acts of blasting, the key trainees are the front-line workers and the key unsafe acts are lay outing the blast holes and charging the blast holes against the regulations and blasting under unstable roof. 4) For unsafe acts of general unsafe acts, the key trainees are mining operation workers, blasting operation workers and transport operators of the front-line employers and the key unsafe act is working at the site without support or with ineffective support. 5) For unsafe acts of regulations and measures, the key trainees for are the front-line employees and middle and front-line management and the key unsafe acts are supporting against the operation instructions, failing to make safety technical measures directing at the complex geological conditions and stress concentration and failing to make operation instructions for the work. 6) For unsafe acts of prop recycling and roof caving, the key trainees are the front-line employees and the key unsafe acts are recycling the props with striking the lock manually instead of using machines, leaving a wide distance over control between the permanent support and the working face, failing to cut the net before caving lower leaf and failing to cut off all the net covering the roof for the first caving. 7) For unsafe acts of supervising and monitoring, the key trainees are the senior management, middle and front-line management and on-site commanders and the key unsafe acts are failing to supervise the worker on site and failing to designate a person to observe the roof during work. 8) For unsafe acts of driving, the key trainees for are the on-site commanders and front-line employees and the key unsafe act is failing to make safety guard. 9) For unsafe acts of mining, the key trainees are senior management and middle and front-line management and the key acts are planning illegal production and laying out the roadways randomly. 10) For unsafe acts of labor organization, the key trainees are on-site commanders and front-line employees and the key unsafe acts are maintaining the roadways from inside to outside, supporting with the wrong order at the rise or dip and assigning intensive operations. 11) For unsafe acts of working at risk, the key trainees are front-line workers and the key unsafe acts are failing to stop the illegal operations of the workers in time and refusing to accept other’s persuasion. 12) For unsafe acts of escaping, the key trainees are front-line workers and on-site commanders and the unsafe act is failing to evacuate the workers when discovering the risk of roof caving. 13) For unsafe acts of removing hazards, the key trainees are front-line workers and middle and front-line management and the key unsafe acts are failing to remove the float coal timely and failing to maintain the decayed supporting facilities. 14) For unsafe acts of supporting, the key trainees are on-site commanders and front-line workers and the key unsafe acts is supporting incorrectly. 15) For unsafe acts of instructing, the key trainees are middle and front-line management and on-site commanders and the key unsafe acts are changing the operational programs against the superior instruction and commanding the workers to work against the regulations.To study the unsafe acts overall, conclusions can be drawn that the unsafe act of supporting incorrectly occurs the most frequently. Unsafe act of working at the site without support or with ineffective support ranks the second. Analysis according to the personnel types shows that the unsafe act of working at the site without support or with ineffective support occurs the most frequently among the front-line workers, the unsafe act of supporting incorrectly occurs the most frequently among the on-site commanders and the unsafe act of failing to supervise the workers on site occurs the most frequently among the middle and front-line management and senior management. All the roof accidents in this dissertation involved a total of number of 179 unsafe acts which occur 1215 times in all. Among them, 151 are contrary to the regulations, accounting for 84.4% of the whole unsafe acts. Four types of unsafe acts violating the regulations exist in roof accidents, namely, acting against the regulations, operating against the regulations, acting complying with the regulations and instructing against the regulations. They are put down according to the times they occur. Unsafe acts of acting against the regulations occurs the most frequently. The key ones of different types of unsafe acts violating the regulations are obtained through analysis. The writer also point out the main unsafe acts of the four types of personnel among every type of unsafe acts and the key trainees for the main unsafe acts.From the perspective of the relevance and practicality of accident prevention, one of the most important tools is to learn accident cases. According to the statistics of roof accident cases, animated video will be used as a carrier of accident cases and behavior-based accident causation “2-4”model will be integrated into the production of the animated videos. Animated video as a training tool should include six aspects: accidents, unsafe acts and unsafe states, unsafe habits, accidents loss, safety management systems, safety culture. By two typical roof accident of coal mine, showing the entire accident prevention design of case presentation video production process. Through the study of animated video coal mine staff master the knowledge of the case, make unsafe acts in their mind and enhance their safety knowledge and safety awareness. Then develop good safety habits and ultimately achieve the effect of correcting behavior and preventing roof accident in coal mine. |
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