Study on the Process Optimization of Fully-Mechanized Hard Top-Coal Caving with Large Inclination Angle

In order to solve the problem of low recovery rate of top-coal during fully-mechanized coal caving with large inclination angle, the optimization of fully-mechanized hard top-coal caving with large inclination angle is studied in this paper respectively in the two aspects of changing caving characteristics of top-coal and caving process. By adopting the method of top-coal pre-blasting to weaken top-coal, the caving characteristics is effectively improved which creates conditions for the successful caving of top-coal; meanwhile, the statistical result of recovery rate of top-coal is obtained by using numerical simulation software PFC2D based on particle element model, it is found that coal loss during top-coal caving and the loss at the ends of working face is effectively reduced when 2 cuttings and 1 caving method with multi-round spaced drawing is taken, which significantly improved the recovery rate of top-coal and it has passed the field test of industrial experiment. This technological achievement could provide some reference to the fully mechanized working face in this coal mine or working faces under similar geological conditions.