Shield resistance analysis of 7 m large mining height fully mechanized longwall face in 52 coal seam of Daliuta coal mine

In order to improve the rationality of selecting shield supports and realize safe and efficient production of 7 m large mining face,field monitoring of the abutment pressure during initial mining,normal retreat mining and last mining is conducted at 7 m large mining height face 52303 and 52304 of Daliuta Coal Mine.The monitoring results show that the periodic weighting in large mining height face is obvious that occurring with rib spalling,roof sagging and possibly roof falls.The shield resistance is high in the middle section and low in the two end sections along the dip direction of the mining face.The characteristics of the shield resistance are analyzed with empirical and theoretical formula.The rational shield support resistance was obtained based on the overburden strata movement and structure,i.e.16800kN shields are in high level operation and 18000kN shield resistance is relatively low.The shields used in 52 Coal in Daliuta Coal Mineare not satisfy the safe production requirements,the rational shield support resistance should be 18550~21586kN.