Subsidence control by coordinated full-area mining of thick coal seam and its application in mining under villages

In China, some coal resources are severely stagnated by buildings, railways, water bodies and others, and there is a contradiction between the recovery of stagnated coal resources and the protection of protected objects. It has been a technical problem for a long time to find a solution to the problem of a high resource extraction rate and the safety of protected objects in China’s mining subsidence research field. In view of the problems of low recovery rate of stagnant resources by strip mining, high cost by filling mining and difficulty by implementing synchronous coordinated mining, this paper puts forward some technical ideas of coordinated control of combinations with horizontal mining width control, vertical stratified mining thickness control and mining sequence control of thick coal seam under villages. In addition, the subsidence control methods of three stages of skip mining, full-area mining and stratified mining of working face are proposed. In order to improve the application effect of the technology, the single wing layout of the development system and the optimization design of large mining area and long working face are put forward. Through some actual measurements and theoretical analysis, the mechanism of coordinating all-mining method to accurately control surface deformation and improve the process and distribution of village surface deformation is revealed, and the optimal design parameters of working face at each stage of mining are obtained. After 20 years of application research in several mines with different coal thicknesses and mining depth conditions, a large number of stagnated resources have been extracted, and the safe and efficient mining of stagnated coal reserve under several villages has been realized. The mining thickness is 3.5−5.7 m, the jump mining width is 305 m, and the annual coal output is up to 1.28 million t/a, The yield rate of coal pillar in the village has reached 93.5%, which brings some social and economic benefits, avoiding the relocation of thousands of villagers.