# Analysis of Characteristics of Roof Fall Collapse of Coal Mine in Qinghai Province, China
## 3 Analysis and Discussion
### Suggestions  
Complex geological environments have always been a difficult problem in coal mining. If there is no perfect detection means and monitoring system, it will lead to heavy casualties. The roof fall accident of the Chaidar coal mine in Qinghai has brought a painful lesson to the Chinese people (20 people died). For future coal mining in complex geological environments, this paper puts forward the corresponding countermeasures from three aspects: monitoring, protection and management:  
(1) Geological conditions, climate change, mining methods and many other factors will have an impact on coal mining. Therefore, it is necessary to conduct risk analysis on the local environment and the situation of the coal mine, classify the risk level, and formulate a safe and reasonable mining plan to ensure the safe and effective mining of the coal mine. The available risk analysis methods include analytic hierarchy process, fault tree analysis, etc.  
(2) It is suggested to strengthen the monitoring frequency of both ground pressure and coal seam water content distribution and to summarize the dynamic ground pressure and coal seam water content distribution in time. With the continuous excavation of the working face, the direct roof strata collapse for the first time, causing the loss of the arch  
Figure 7: Cumulative daily rainfall in August in Gangcha County.  
effect. This process produces an increase in ground pressure and then the roof collapse may happen at the working face. On the other hand, the disturbance of secondary stress leads to the development of cracks in roadway-roof-surrounding rock, resulting in the increase in water content. With the increase in water content, the strength and elastic modulus of mudstone show a downward trend, which further weakens the strength of the roof-surrounding rock. Some new coal-mine-monitoring systems can be developed, e.g., the neuro fuzzy system, optical fiber sensing technology, etc. [51]. These new monitoring systems can deal with the influencing factors related to roof fall accidents so that the potential changes in ground pressure and water content can be predicted [52; 53; 54].  
(3) Some novel roof support system could be adopted in combination with the field situation of the construction site. According to the existing research, the transportation and layout of anchor mesh in the permanent support operation of the coal mine roadway mainly rely on workers' operation, which has the problems of low work efficiency, high labor intensity and high risk. Recently, an anchor net transportation robot system with automatic net operation has been proposed [55]. A three-dimensional model is established by SolidWorks in the robot system, and the mechanical analysis of the structure can be conducted. The working process includes establishing the operating mechanism of the system, establishing the kinematics model, analyzing its workspace and solving the motion trajectory. The robot system has strong reliability, high stability and high transportation and placement efficiency [56]. In addition, other new techniques, e.g., the Internet of Things (IoT) technique, can also be used to monitor the mechanical response of support systems in real time, which could provide effective information for the assessment of the safety of the support system.  
(4) It is necessary to strengthen the training of miners and to improve the safety awareness of construction personnel. It is essential to regularly conduct safety construction training and education activities for construction personnel and management personnel, so that everyone in the mining area can establish a correct safety concept, enhance safety skills and improve safety awareness.