Study On The Backfilling Mining Method And Earth Surface Subsidence Mechanism Of Repeated Mine

"Three undergroud" repeated mining is always a mining problem. On the one hand, it needs ensure the safety mining possibility of repeated mining coal seam, on the other hand, it also needs reduce the surface movement and deformation caused by mining which is a high requirement for mining technology Taking4#repeated mining area of Ruifeng coal mine as the typical research object, this paper describes the studies of mining methods, technology and application of "Three undergroud" repeated mining. Firstly, according to the technical and safety analysis, the paper analyzes the feasibility of "Three undergroud" repeated mining and then establishes evaluation mode) of "Three undergroud" repeated mining recoverability. Based on the actual mining conditions of4#repeated mining area, through the feasibility study, backfill mining method is chosen. Then, through the research of "Three undergroud" backfill mining method and process in the repeated mining, backfill mining mode and filling process with mixed materials (coal mine waste discrete material with superhigh water material) have been proposed. Finally, according to the numerical calculation and on-site observation and research of the backfill repeated mining process by using DEM, the coal strata movement and regularity of mine pressure of "Three undergroud" repeated mining are exposed.The research of this paper has been successfully applied in the process of4#coal mining and achieves significant economic and social benefits, which has promotion significance and application prospects.