Application status and prospect of backfill mining in Chinese coal mines

In order to fully understand the feasibility of backfilling mining in coal mines,the State Administration of Coal Supervision organized a systematic investigation on the present situation of backfilling mining technology in Chi- na,and obtained detailed data of various backfilling mining methods in different areas and different shaft types of coal mines in China. The production practice of backfilling mine shows that the backfilling mining can eliminate the pollu- tion of waste rock dump to ecological environment,effectively restrain the surface subsidence,protect the surface and groundwater resources,avoid the damage of ground infrastructure and buildings and the relocation of villages. It re- duces the possibility of underground goaf water,gas accumulation and spontaneous combustion of floating coal,and ob- tains some ecological and social benefits. It is found that many mines in China are still facing the problem of ecological environment destruction,some of which can be solved by backfilling mining,but the proportion of coal mines that really choose to solve their practical problems by backfilling mining and persist in long-term backfilling mining is very small. Through in-depth investigation,the problems existing in the process of backfilling mining are understood,and the large construction investment in the initial stage of backfilling mining is analyzed. The main factors that restrict the development of backfilling mining in China are long period development,high cost,shortage of backfill materials,poor backfill capacity and lack of policy incentive. Based on the survey results,this paper discusses the demand degree of regional economy,ecology,resource endowment,industrial characteristics and industrial policy for backfilling mining. Also,the principle of preferential selection of backfilling mining method in different areas and mines with different shaft types, the source of backfilling materials and key areas of backfilling are analyzed. The development prospect of backfilling mining technology and equipment in China is studied,and the technology route of backfilling and retaining is put for- ward by using precise backfill to construct ecological mine and underground mining.