Engineering design and application of solid backfill mining method in mines under embankment

Mining under the surface water body or embankment is not uncommon in many countries, but its ratio of recovery is hardly satisfactory. This paper introduces a novel mining attempt at Jining No.3 coal mine where solid backfill mining method was first applied to exploit coal buried under Nanyang embankment. According to the embankment structure and the existing solid backfill mining method, we designed the values of critical deformation and the aiming value of backfill body compaction ratio (BBCR) in the goaf Combining the probability integral method and the equivalent mining height theory, the horizontal deformation in the first mining face and the whole trial area was predicted, which proved this trial practicable. A monitoring line was set up to observe the influence of mining on the embankment. So far as monitored, the observed values of the embankment deformation were lower than predicted, which means the influence of extraction was little to the normal operation of embankment. The practicable trial of Jining No.3 coal mine using the solid backfill mining method can provide a reference for mining under the similar conditions.