... 400-400kN/m for long-wall recovery system roof support,hock mining geogrid,Shandong Hock MiningMine Grid ... blast areaSlice mining longwall facesDeclining longwall faces for roof supportMine Grid Characteristics:Large square, flexible and light ... out together with the coal-splitting, pushing and support advance, therefore, the working speed steps up. ... longwall recovery system,rib and roof support