New Technology of Three-Dimensional Gas Drainage Combined Hydraulic Fracturing Roof with High Level Drilling Borehole

According to the unstable, soft, broken, low permeability and other actual conditions of the seam in XinDan Mine, the new technology of three-dimension al gas drainage combined hydraulic fracturing roof with high level drilling borehole was conducted. The trial study showed that the hydraulic fracturing conducted in the seam roof surrounding rock and the seam could form rich cracks. The seam pressure released, while the gas permeability of the seam would be obviously improved. Th e high level boreholes were arranged for three dimensional gas drainage in the influence scope, and the gas content of the seam was reduced to 2.3 m3/ t. The averag e pure gas drainage value from the fractured borehole was increased from 0. 004 m3/ min to 0. 216 m3/ min. The daily accumulated max pure gas drainage value was i ncreased from 8.4 m3to 392. 4 m3, the gas drainage rate was efficiently improved and the gas utilized conditions could be met. Thus more rational and high efficient te chnical support could be provided for coal and gas outburst prevention and control in XinDan Mine.