In order to provide basis of accident-causing mechanism, the relationships between the hazards and accidents is studied in depth. As demonstrated in Fig. 1, the status hazards consist of the identified status hazards and unidentified status hazards. Firstly, because of the limited knowledge of human, the identification of status hazards exist blind area, namely exists the unidentified status hazards which are directly in a status of non-defense. Consequently, the unidentified status hazards are the biggest threats. Therefore, comprehensive and in-depth identification of status hazards, namely eliminating the blind areas, is paramount in avoiding accidents. Secondly, control criterions and control measures should be setup to manage the identified status hazards. The control criterion is the control of hazards to what extent can eliminate the risk of hazards, which can be formulated according to relevant state criteria, industry criteria, and manufacturer criteria. The control measures are methods or means to achieve control criterions. If the identified status hazards meet the control criteria, they are called controlled status hazards which do not have the potential to trigger accidents as shown in Fig. 3. If the status hazards do not achieve the control criterions, they are considered uncontrolled status hazards which result in out of control operations that could potentially trigger accidents under some conditions. As an example, gas concentration in the mining coal face is the identified status hazards, and ‘‘Gas concentration less than 1%” is the control criterion. If the gas concentration meets the control criterion, it is in control;otherwise, it is out of control and called the uncontrolled status hazards. Once the identified status hazards go out of control, it is crucial to take some rectification measures to correct them and make them return to normal and safe status. Therefore, the control criterions, control measures, and rectification measures are called ‘‘three layer of defense” of the risk control management of safety in coal mines, as shown in Fig. 3. If the hazards break through the ‘‘three layer of defense”, an accident is likely to be triggered.