Yield process of the 1150-m horizontal jamb in Jinchuan No. 2 Mine area

In Jinchuan No.2 Mine area,two mining levels with different altitudes were resulted from the backfilled mining in large hypogeal area without micro-jambs,and the ore-body between them called a macro-horizontal jamb was distinguished as seven mechanized panels.In 2004,the thickness of the east part was smaller than that of the west part in the macro-horizontal jamb,especially the smallest thickness appeared at the eastern second mechanized panel was only about 32 m.A three-dimensional finite element model was constituted to simulate the yield process of the macro-horizontal jamb in the tectonic stress field caused by continuous mining.It was indicated that the yield process began at the east firstly,then spread to the west,and in 2005,all mechanized panels besides the seventh one attained the destroyed situation within the macro-horizontal jamb.Based on the calculated results,it was predicted that in 2005 the mechanized panels would appear obvious submergence phenomena,which had been already proved by the local observations in 2006,and it was considered that the counteractive effect of the macro-horizontal jamb with high stress concentration ever resulted in the worst structural distortion of drifts would decline quickly and become a minor factor.Therefore,it was advised that choosing a new mining plan with respect to all mechanized panels should not be necessary to the macro-horizontal jamb in the future.