Study on Strata Behavior Laws at Hard Roof Working Face in Jincheng Mining Area

Aiming at the non-clear problem of strata behavior laws in 15# coal hard roof of Jincheng Mining Area during the mining process,using similar material simulation test and field measured,the strata behavior laws in hard roof are analyzed,the results show that the first caving of immediate roof is 22. 3 to 23. 1m,average 22. 7 m; the periodic caving interval is not obvious; the first caving of basic roof is 52. 3 to 55. 1 m,average 54. 2 m; the periodic caving interval is 17. 1 to 19. 4 m,average 18. 2 m; the violent influence range of advanced abutment pressure of working face is 30 to 35 m.