3.2. Accident-causing mechanism based on hazards
The accident-causing mechanism in coal mines based on hazards can be obtained according to the above analysis of relationships between hazards and accidents, which is shown in Fig. 3. From the sequence of accidents in Fig. 3, it is clear that if the status hazards are not identified, they will directly break through the ‘‘three layer of defense” which includes control criteria, control measures, and rectification measures, and then trigger accidents under some conditions. It is also clear that the uncontrolled status hazards can give rise to accidents in the case of ineffective rectification measures. Fig. 3 also highlights that if the control measures fail to make the identified status hazards meet the control criteria, they will evolve into the uncontrolled status hazards.