Comprehensive Gas Drainage Control Technologies in Fully-Mechanized Top Coal Caving Mining Face

According to the problems of mining depth continuously increased and seam gas content steadily increased in Baode Mine, the gas comprehensive contr ol mode of deep seam was established. A gas drainage method combined with a borehole along mining seam and 1 000 m borehole was applied to coal mining face, a gas pre- drainage method of a mather gateway and assistant gateways was applied to the gateway driving face, and a gas drainage method with pipeline buried in the C onnection gateways was applied to the mining goaf. The results showed that after above gas comprehensive drainage and control technologies applied, the gas drainag e concentration of the coal mining face and the pre- drainage rate were all over 10% and residual gas content was controlled below 4.5 m3/ t. The residual gas content of driving face was reduced below 4.5 m3/ t, a residual gas pressure was all reduced below 0.2 MPa and the max gas content in the driving face and in the air retuning flow was all below 0.3%. After the goaf gas were drained with the pipe buried in the connection gateway, a gas content at the upper corner of the coal mining face was reduced from previous 0. 6% in average to below 0. 3%. After a gas drainage pipe applied to the goaf, the max drained gas net quantity was 13. 60 m3/ min. The highes t gas concentration was 40%. The gas comprehensive drainage technology applied could effectively reduce the gas content of coal mining face and could effectively en sure the safety and high efficient mining.