Roof Cutting Mechanism and Control Technology of High Cutting Coal Mining Face Passing Through Large Cross Section Abandoned Gateway

In order to solve the roof cutting and roof falling problems occurred when the high cutting coal mining face passing through large cross section abandone d gateway, a theoretical calculation and site observation method were applied to analyze the roof cutting accident occurred in No.12211 high cutting coal mining face of Shangwan Mine. With the analysis on the migration features of the roof strata during the coal mining face passing through the abandoned gateway, the support intensity check of the abandoned gateway and the periodical strata pressure weighting law of the coal mining face, the causes of the roof cutting accident were obtained. The act ual supporting intensity of the abandoned gateway was 0. 108 MPa only and was far lower than the theoretical supporting intensity of 0.960 MPa. The two ribs supporti ng intensity of the abandoned gateway was insufficient and caused large area spalling on the two ribs of the abandoned gateway. During the period when the coal minin g face passed through the abandoned gateway, the influences by the periodical strata pressure weighting of the coal mining face would cause the roof cutting and spali ng accidents occurred in the coal mining face. With the actual supporting intensity of the abandoned gateway enhanced, the two ribs support enhanced and the waiting periodic weighting measures conducted, the accurate peridical roof strata pressure weighting law prediction and other methods were applied to effectively control the「 oof cutting and spalling accident occurred and ensure the high cutting coal mining face safely passed through the abandoned gateway.