The mining system in the deep mine of Yunnan Chihong Co. was designed by ENFI. In the backfill mining system adopted in the mine, the paste fill, consisting of unclassified tailings, water-crushed slag, waste rock and cement, would be delivered for placement by pumping. The designing conception proposed a goal that a clean waste free mine would be built in which tailings would not be transported to a tailings dam [(and waste rocks would not be hoisted to a surface stockpile.)0( )][(