Determination on Rational Location of Two Gateways in Coal Mining Face Under Goaf with Ultra Short Distance to Mining Seam .

In order to make a rational layout of the two gateways in a coal mining face in a slicing seam under ultra short distance to the top seam,an elastic and pl astic mechanic theory was applied to calculate the max yield depth of the floor on the top slicing seam mining face.The floor failure depth was 8.29 m as obtained.The F LAC3D numerical simulation software was applied to analyze the top slice seam mining affected to the floor.With simulation on the mining process and gateway driving i n the adjacent coal mining face,the floor failure process and the inner stress variation were obtained and the rational location of the two gateways in No.22104 coal mini ng face in the low slice seam was determined as 85 m and 300 m individually and horizontally to the air retuning gateway of No.22102 coal mining face in the top slice s eam.The actual measurement of the gateway deformation was conducted.There was no obvious deformation and failure of the gateway occurred in the observation are a.The results showed that the application of the floor failure depth,the low stress zone under the goaf and other conclusion to determine the rational layout mode of the two gateways in the low slice seam mining face was feasible.