Analysis on overburden strata movement law of coal mining face under goaf of room and pillar mining face

Based on the mining conditions of a shallow depth seam under the goaf of ythe upper seam in a mine in West China mining area,a KJ768 microseismic mon itoring and measuring system was applied to analyze the cracking features of the overburden strata above the coal mining face. The paper discussed the overburden strata movement law under the goaf of the room pillar mining. Analysis and practices was conducted on the prediction of the large scale subsidence movement of the overburden strata. The results showed that with the coal mining face pushing forward,the microseismic accident would have the dynamic development features,the microseismic accide nts would be distributed at about 200 m in front of the coal mining face and there were microseismic accident distribution in the roof under the goaf of the upper steam and the roof strata above the coal mining face. Based on the multi roof movement conditions ,according to the certain microseismic early warning index Analysis and practices W as conducted on the prediction of the overburden strata movement above the coal mining face under the room pillar mining goaf in the upper seam. Based on the analysis achievements,the mine had made the measures to reduce the coal mining face forward speed,to rationally control the mining height and others to ensure the safety product ion of the coal mining face.