Study On Surface Movement Law Of Slope Coal In Heidaigou Open Pit Coal Mine

The first mining area of Heidaigou open-pit mine is completion and the working slope will turn to the second mining area,under the west side slope and southwest slope have part of coal resources in the first mining area,to adopt longwall mining with sublevel caving method recovery the part of coal under the west side slope and southwest slope.Because the Heidaigou open-pit mine side slope is stepped slope,the stratum slope missing,by the open-pit loose crushed rock material pressure,making the coal mining face rock and overburden failure and surface movement laws under normal circumstances are different.Therefore,it is very important to study longwall mining with sublevel caving method recovery the coal under side slope caused by surface movement regularity and rock pressure,ensure the open-pit coal under slope safe and efficient exploit.Through the pressure situation of research area stope position,geological data and establishment of geological model,dump solid model,coal solid model and solid model of stope pressure,as the base of the numerical simulation and calculation of underground mining design.The dynamic stress field,displacement field and failure field of the overburden are studied by using FLAC software,and analyzed surface movement west side slope and stope around the pit slope deformation trend.The results show that the stress of the surrounding rock is smaller than that of the overburden strata,and it is proved that the existence of masonry beam protection in the overburden strata is proved by the similar material simulation test.The theoretical analysis and experimental calculation show that the surface subsidence of the composite coal seam at the western end of the sixth coal seam is 10?16m,and the maximum settlement width is 5m,The maximum fissure width of the dump is about 3m,the influence angle of the rock movement is 60°?67°,and the influence of the loose media movement is 34°?41°.And determine the impact of the well mining on the open-pit mine ground construction production facilities affected areas,the scope of the relocation and the need for additional industrial production site location.The research results of the paper not only provide the basis for the design of the coal mining work in the west side slope part of the first mining area of the Heidaigou open-pit mine.At the same time,it is a great significance to study the failure of overburden and the law of surface movement in open-pit mine.