Abstract: A method for stepwise construction of a preferential gas migration pathway at a stope in a coal seam. First, a gas migration pathway is preliminarily formed at a stope depending on a mining effect of mining in a first mined seam. construction and stabilization method of gob-side entry retaining in deep strata, and a method of manual-guided pre-fracturing boreholes are then used to perform active construction respectively in external space and the outside of coal-rock mass to form preferential gas migration pathways. Eventually, under the effect of mining-induced stress, a system of preferential gas migration pathways connected to each other at the stope is further formed.

Abstract: The present invention relates to a method for sorting and utilizing coal and rock for a coal and rock combined mining face, and is especially applicable to the sorting and utilization of coal and rock mined from a coal and rock combined mining face when an extremely thin coal seam is used as a protective layer in combined mining of multiple coal seams.

Abstract: A method for stepwise construction of a preferential gas migration pathway at a stope in a coal seam. First, a gas migration pathway is preliminarily formed at a stope depending on a mining effect of mining in a first mined seam. construction and stabilization method of gob-side entry retaining in deep strata, and a method of manual-guided pre-fracturing boreholes are then used to perform active construction respectively in external space and the outside of coal-rock mass to form preferential gas migration pathways. Eventually, under the effect of mining-induced stress, a system of preferential gas migration pathways connected to each other at the stope is further formed.

Abstract: A method of performing coupled drilling, flushing, and slotting operations on a coal seam, which has a high gas content and prone to bursts, is described herein. The method is aimed to relieve pressure and increase permeability when drilling a through-seam borehole to pre-drain gas belts in a coal mine roadway. The pressure relief and permeation method of the present invention adjusts the water jet water inlet pressure in different stages according to the different positions of the drilling construction, and controls the water during drilling. At drilling stage, the jets are respectively subjected to low-pressure water flow drilling and medium-pressure water flow flushing. When withdraw drilling, the high-pressure water flow slotting is carried out. By doing so, the pressure is relieved in a low, medium, high stepwise manner.

Abstract: The present invention relates to a method for sorting and utilizing coal and rock for a coal and rock combined mining face, and is especially applicable to the sorting and utilization of coal and rock mined from a coal and rock combined mining face when an extremely thin coal seam is used as a protective layer in combined mining of multiple coal seams.

Abstract: The present invention relates to a “drilling-flushing-slotting” coupled pressure relief and permeability increasing method for a high gas outburst coal seam, which is more particularly suitable for the pressure relief and permeability increasing when gas of a roadway band of the high gas outburst coal seam is pre-extracted through crossing boreholes. On the basis of the crossing borehole pre-extraction measures for the coal seam gas, the hydraulic flushing and the hydraulic slotting are reasonably combined, and a “drilling-flushing-slotting” dedicated device is utilized to implement the coupled operation of “low pressure drilling-medium pressure flushing-high pressure slotting” in a borehole, so that the coal in the pre-extraction area is deformed and moved to form network cracks, passages are provided to the desorption flow of the gas, and the gas is easier to extract.