Namerical modeling for natural grade classification of the loose-covered covering rock

The natural grade classification of loose-covered rock has a great effect on caving mining efficiency in the mines using sublevel caving without sill pillar. This paper adopts the computer simulation technology on the basis of discrete element method, studies movement process, movement direction and movement pattern of rock block of covering rock, builds mathematical model and develops simulation software RB_DEM. Through simulation of RB_DEM, the existence of natural classification phenomenon is confirmed. it provides a new way for reducing the loss and dilution of ore.