Fine sand, less than 37μm, in gangue can not be used as dam materials during selecting mine. After the classification by cyclone, coarse granule left in the bottom of dam, fine granule move to the tail of gangue. Fine granule graded naturally during the movement. There is section full of clean water, which can be used for calling back of water. In the process of filling tail, we utilize cyclone for grading and concentrating to separate coarse granule so that to reduce load of filtering machine and to reach at the best effect. Use cyclone to finish dam and filling work so that to solve problems such as leaking mine, sink and overproof water discharged. So it can receive obvious economic and social benefit.