Research on weighting characteristic of longwall top-coal caving face in different mining periods in two-direction thickening coal seam

In terms of the complicated mining technical conditions of 15081 fully mechanized caving face of Jiulishan mine in Jiaozuo mining area, the basic roof weighting step and weighting strength in the initial mining period, partial coal caving period and fully coal caving period are studied.Based on theoretical calculation and field monitoring, the weighting characteristics of the face in different periods are revealed:with the enlargement of caving range, the weighting intensity of the whole face will gradually decrease until it is disappear.Compared with the fully caving period, the periodic weighting step distance of partial coal caving period is not much longer, the weighting strength and the level of working resistance of daily support are slightly higher.It provides theoretical guidance and field experience for safe and efficient green mining in the coal and gas outburst mine.