Blasting parameter of compulsive roof cave-in

The mechanics intensity in the Yu-Sheng Coalfield is not great,it belongs to the non-hardy roof. But the main roof at the first weighting is very big. The individual jacks can not dispute the pressure which is caused by the over burden's holistic collapse and the massive collapse of the main roof,it easily initiates the working face always emerge massive collapse catastrophe. Numerical simulation indicates it is feasible nature to reduce collapse distance at the first time in the face with deep and shallow blasting. Through numerical simulation and mining analysis,the compulsive roof cave-in method to avoid massive collapse catastrophe is brought forward. The relationship between the minimum resistance line and the diameter is obtained,and the reasonable blasting parameters is confirmed,providing a reliable basis to avoid massive collapse catastrophe.