Method for filling heavy-pitch coal bed goaf

The invention discloses a method for filling a heavy-pitch coal bed goaf, comprising the following steps: firstly, arranging a grouting pump and a belt conveyor for transporting gangues in an upper roadway on a heavy-pitch direction long-wall coal face; every time the coal face is forwards pushed for 1.2-1.8m, arranging a grouting pipe on the top plate of a strut at the last row; after the coal face is pushed for 3-5m, stopping pushing; arranging air cushions along the strut at the last row on the whole coal face except the upper roadway; filling a gas to cause the air cushions to expand; communicating the grouting pipe on a goaf top plate sealed by the air cushions with the grouting pump; transporting the gangue to the upper tip of the coal face to cause the gangue to automatically slide to the goaf; after the goaf sealed by the air cushions is filled with the gangues, stopping transporting; then, grouting into the goaf to cause the gangues to be fully cemented; stopping grouting, removing the air cushions, and forwards pushing the coal face; and repeating the above steps until the whole goaf is filled. The method is convenient to operate and simple to construct. After the gangues are filled, the possibility of sinking for the top plate can be lowered, the gangues can be reused, and the cost on processing the gangues is lowered.