To overcome the deficiency of current risk pre-assessment method

the II class mining technical factors are defined and pointed out to reveal how the II class mining technical factors inherently induce the abnormal vibrations of coal and rock

and trigger disasters.The results show that: the greater the rate of face advance mining

coal and rock shake more frequent and the greater probability of the high-energy shock event

To decrease in low-level microseismic events

and high-energy event frequency increased

overall microseismic activity enhancement when the workface with a uneven advance rate

The method of blasting to relief stress in coal seam aimed the burst start-up areas of the roadway's sides

So the energy released of per kg dynamite during blasting much larger than the amount of energy released of blasting in roof or ground; the 7-18 h is the most effective period of dangerous lift. The original balance of stress field were broken by the repair in roadway's sides; the wall rock from a relatively stable state becomes unstable; the greater the rate of repair in roadway's sides

and the greater probability of the high-energy shock event. A sharp rise in the various levels of microseismic events

and the risk associated with high-energy events because of the ceasing and recovery production of workface.II class mining technology factors temporary intervention

breaking the original balance state

make coal rock macro adjustment

micro fracture suddenly disorder

stimulate coal rock impact events occur.