Abstract:  In this paper, to evaluate the goaf backfilling effectiveness with solid wastes, the final compression ratio of backfilling materials was proposed as the technical measurement index, and the associated key affected factors were also analyzed. The results show that the three key affected factors of compression ratio include the roof subsidence before backfilling, the gap between the backfilling body and roof, and the compression amount of filling materials. Hereby, to improve the final compression ratio of backfilling materials obviously, the structures and the parameters of filling equipment were optimized, the filling technology was upgraded, and the supervisory control system of compression ratio was also established. The above achievements have been successfully applied in No.12 mine of Pingdingshan coal group. The application results show that the actual final compression ratio of backfilling materials in the goaf is up to 89.4% and the maximum surface subsidence is merely 15 mm, thus ensuring the safety of surface buildings.

Key words: fully mechanized coal mining and backfilling, compression ratio of backfilling, backfilling technology, supervisory control system