Development and application of high efficiency drilling equipment inhard-soft composite coal seam

In order to solve the problems of the shallow drilling hole of gas drainage and low pore-forming efficiency which occur in the gas control in the boreholes along hard-soft composite coal seam, a powerful drill rig and the matching implements for underground coal mine whose large torque and high speed can be adjusted remotely was developed. The overall structural layout, key performance parameters and the hydraulic system of the new drill rig are firstly introduced. Then the characteristics and functions of its important parts including gyrator, luffing mechanism and cylinder propulsion device as well as the related drilling technology and method are described in detail. Through the industrial test in Changping coal mine in Shanxi Jincheng Anthracite Mining Group, the overall performance of the new equipment under the complicated conditions of hard-soft composite coal seam has been qualified. The results show that the pore-forming efficiency, the maximum borehole depth, drilling efficiency, average borehole depth, and drilling footage per month were improved significantly by using the new equipment.