Coal wall spalling mechanism and prevention technology of unstable seam with soft roof,soft coal and soft floor

Abostract : n order to prevent and control the roo faling accident caused by the coal wall spling occured when the suspended moving suports applied to the mechanized coal mining in a coal mining face in a unstable sean wth " a softroo,soft coal and soffoor :withthe analysis on the spaling mechanismn of the sliding ype spalling and hearing type spaling in the unstable seam wih " the soft o.sot cal and sot foor and the spalling prevention and conroltechnolcgy of the cal a. cording to the main features of the coal wall palling ocured in the mechanized coal mining face in the unstable seam with " the sot of.sof coal and sot for a combination with a wooden boling and seam water injection was set up and conducted at the topof the coal wall n the coal mining face and the comprehensive measuresof the coal wall palling prevention and conrol were conducted to enhance the support-surounding rock system management and to optimize the mining fechique. The ite est resuts showed that afer thecomprehensive saing prevention and conrol measures implemented in the mechanized cal mining facein the unstable seamwith " the soft roof,soft coal and soft floor" the spalling ratio with a depth over 0.3 m was reduced from 52.6% to 12.5% 0.82 m to 0.42 m.The spalling in the coal mining face was effectively controlled.