| With the fall of mining depth in Xitie Mountain Lead-Zinc Mine,the gradually increasing of narrow vein,the short shrinkage method becomes more and more adoption.In this paper,the short hole crater reaming and undercutting two steps method,which is formed bottom structure in short shrinkage method,is changed into one step that middle-deep hole crater reaming and undercutting method. The application results show that the productivity is improved,the productive cost is reduced,the good economy and society bene... |