Stability Analysis Of Mined-out Areas And Optimization Of Residual Ore Stoping Sequence At Pumin Iron Mine

Ores are non-renewable resources, so safe stoping of residual ore has remarkable economicbenefit for mine. Different stoping sequence can form different stress distribution, which leads tovarious stope stable state and unstable destroy of rock in severe case. Therefore,with objectiveconditions such as ore-rock properties and geological structure determined, seeking reasonablestoping sequence of residual ore is the key step to ensure the stope stability.In this paper, the stoping scheme of-610meters room and floor for Pumin ore mine isdesigned. Two methods including rock mass classification and numerical simulation are used toanalyse the stability of mined-out area, and the stope stability and optimum stoping sequence of-610meters room and floor is studied respectively.Firstly, after detailed survey of Geological conditions and present mining situations,point-load test is investigated for Pumin ore mine. And based on this, the rock mass is classifiedby RMR method and Q system method, and the rock physical and mechanical parameters andmass quality level of mined-out area is proposed.Secondly, using finite element numerical simulation method,3D model of Pumin iron mineis built by ANSYS. Through analyzing the variation of stress distributing and safety factor inmined-out area before and after residual ore mining, the whole of mined-out area is stable andalso-610meters room and floor has the stoping feasibility.Finally, under the condition that stoping feasibility of-610meters room and floor isdetermined, three practicable mining sequences are proposed based on mine present and designscheme of mine stopping. Compared with stable state of mined-out area in these miningsequences, the optium mining sequence is determined with the minimum influence for thestability of mined-out area as its standard, thus it provides scientific guidance for safe stoping ofmine.