Numerical Simulation of Back Sublevel Fill Stoping with Parallelogramic Stope Structure

The current applications and problems of sublevel filling stoping in Laixin Iron Mine of Luzhong Metallurgic Group were discussed involving such factors as the natural roof caving characteristics of rock/ore at stopes,possible recovery ratio and blasting effect and avoidance of drift driving within fillers.A method of back sublevel filling stoping with parallelogramic stope structure is thus proposed,which is investigated numerical simulation using the 2D-σ software for finite element analysis.The results show that the tensile stress concentration and/or other high stress concentration in rock/ore will not occur in stoping process if applying the method proposed to mining,and the stress in surrounding rock is distributed uniformly along its periphery.And the plastic zone is not found in either wall on both sides of surrounding rock and roof except the filler bottom after stoping.The method is thus proved feasible to fragmentarily bulk ore body in Laixin Iron Mine.Analyzing comparatively the distributions of surrounding rock stress and plastic zones at different heights of sublevel with technological requirements taken into account,the sublevel height is determined to be 10m.In view of the stoping effect on neighboring rooms,it is suggested that the strength of filler should be over 1 MPa.