Water inrush control and restoration of shaft construction in cretaceous aquifer

A water inrush accident,which caused shaft flooding,broke out in Wuju coal mine,China when its main ver- tical shaft was getting through the cretaceous water rich aquifer. The accident characteristics were analyzed and a com- prehensive governance techniques of vertical shaft water inrush control of normal construction in western water-rich aq- uifer was proposed. The techniques ensured the water inrush stopping first by constructing a concrete waterproof pad under a static water level,then carried out a restoration operation of controlled water draining combining with backfill grouting which can maintain the stability of waterproof pad and the shaft side wall,and lastly gradually conducted high pressure deep hole grouting on shaft work face. The design parameters of waterproof pad under water,the proportion of special concrete,and the special hopper bucket design were introduced,and the construction and combinational rein- force technique of waterproof pad and concrete grouting pad were proposed. The comprehensive techniques were ap- plied in the water inrush disaster which caused a flooding level at 145. 68 m and water inflow of 360. 97 m3 / h. The practical experience was accumulated for the normal construction of vertical shaft and water controlling in western cre- taceous water-rich aquifer.