Optimum Selection of Ore-Caving Sequence of stope by Pillarless Sublevel Caving Method Based on Stability of Surrounding Rock in Roadways
Reasonable ore-caving sequence of stope by pillarless sublevel caving mining method is an important means to ensure the stability of surrounding rock of roadways.Taking 12 drift roadways at-410 m level of a metal mine as the research object,the stability of the surrounding rock of the roadways after the mining of the three schemes of the ore-caving sequence of the stope approach from the two wings to the central advance(scheme 1),the central advance to the two wings(scheme 2),and the central and two wings advance face to face(scheme 3)was analyzed.Based on the distribution characteristics of plastic zone,shear stress and strain,the optimal ore-caving sequence scheme of the stope was selected.The results show that on the typical section,the total area of the plastic zone of the surrounding rock of the 12 roadways in scheme 2 is the smallest,and the absolute values of the shear stress and normal strain of the surrounding rock at the midpoint of the roof,floor and side wall of the roadways are the smallest at the vertical distance of 0.5 m from the roadway wall,so scheme 2 is the optimal scheme.Through the stress change monitoring of the mining stress monitoring points arranged at the corresponding position,the results show that the stress change trend in the field mining and numerical simulation is consistent,which meets the engineering requirements.The research results can provide reference for the design of stope ore-caving sequence in similar mines.
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