Theoretical analysis and engineering practice of dynamic pre-reclamation in coal mining subsidence area

In the mining areas with high phreatic water levels in Eastern China, due to the long time and disordered mining of single thick coal seam and multiple coal seams, a large area of unstable settlement and waterlogging areas have been formed, resulting in a sharp decrease in the area of arable land. If not managed in time, it will lead to a series of problems, such as the increase of management cost and the reduction of reclamation efficiency. Based on the concept of "end management" to "source control", "process management" and "combination of prevention and control", and on the basis of the existing research results, the dynamic pre-reclamation was comprehensively analyzed from the principle, advantages, key technologies and other aspects. Combined with engineering examples, the overall technical system and implementation methods of dynamic pre-reclamation were deeply analyzed. The results show that dynamic pre-reclamation can effectively combine mining and reclamation. By means of reasonable zoning, scientific determination of elevation, and effective topsoil peeling, it can effectively protect and utilize the land resources of shallow cultivated soil layers and shorten the time for land restoration and management, and the benefits are significant.