Research on the advance pre-cracking technology of hard roof in fully mechanized short caving mining face with large inclined angle

Large-scale fully mechanized top coal caving mining with small width of working face thick hard roof is not easy to collapse, mined-out prone to large area of suspended roof, gas accumulation and roof collapse dynamic impact and other disasters.Taking Bostan coal mine 1131 working face as an example, the roof breakage of work face is calculated.Through the analysis of the hard roof treatment method, the roof weakening technology scheme is put forward, and a reasonable arrangement of blast holes, blasting parameters and safety technical measures are determined in view of the leading weakening of the hard roof with big dip angle.Through on-site practice, the roof of the working face was promptly collapsed and the mine safety production was ensured.