Application of solid backfill mining techniques for coal mine under embankment dam

To mine coal resources trapped under embankment dams safely and efficiently while, at the same time, disposing of waste rock, solid backfill mining has been proposed as a solution. The extreme value of dam deformation was obtained by analysing geological conditions in the area and structural characteristics of the dam. It was determined that the filling ratio of the working face and the equivalent mining height were the two key factors that control dam deformation. In addition, the extreme values of these two key factors varied with the distance between the working face and the embankment dam in a regular pattern. When mining was completed at the first working face in the pilot area, the maximum sink value of the dam was 42 mm, and the maximum horizontal strain was 0·16 mm m−1. Field demonstrations have shown that solid backfill mining is effective in controlling strata movement and surface deformation.