1.Chongqing Research Institute,China Coal Technology and Engineering Group,Chongqing ,China；2.Xinjiang Coking Coal Group Corporation Limited,Urumqi ,China

In order to solve a high engineering quantity of the gas drainage borehole drilling for the seam opening of the crosscut in the low permeability seam and a long gas drainage time,a combined fracturing and permeability improvement technology was applied to the seam opening of the crosscut. In No. 5 and No. 6 seam opening processes of +1 830 m horizontal air return crosscut in 2013 Coal Mine of Xinjiang,a fracturing borehole was constructed only and three rubber capsule packers were applied to accurately set up the borehole sealing location. Thus the fracturing points avoided the rock borehole section and the coal and rock interface and the combined fracturing operation was conducted simultaneously in the two seams. The research results showed that the combined fracturing and permeability improved technology could realize the combined fracturing of two seams. After the fracturing operation,the water content of the seam was obviously increased and the influence radius of the fracturing was over 14 m. After the fracturing,the permeability of the seam was obviously improved and there would be no obvious attenuation phenomenon occurred in three months of the gas drainage. In a comparison between the combined fracturing and permeability improvement technology and the traditional gas pre-drainage mode along in a single seam,a daily average gas drainage volume fraction and the gas pure volume were increased by about 2.3 times and 3.8 times,the drilling amount was reduced about 75%,the gas drainage time was reduced about 60% and the total construction period was reduced about 70%.