Novel reverse-circulated excavating-drilling fluidized mining technique for steep-inclined coal seam

Abstract

The steep-inclined coal seams are widely distributed in western and southern China.These coal seams are complex and difficult for fully-mechanized coal mining.Therefore, developing a novel fluidized and intelligent mining method to recovery the steep-inclined coal seam is of great significance to ensure the safety production of coal.This paper proposed a reverse-circulated excavating-drilling method.A novel fluidized reverse-circulated mining machine was designed and the composition and utilization of this machine were introduced.Afterwards, the parallel excavating and drilling method of this machine is proposed.Finally, the coal mining efficiency, recovery rate and high-pressure water jet assisted coal cutting of this method were calculated.Results show that a larger diameter of cutting head always implies a greater coal mining efficiency.It is necessary to select a suitable diameter and overlap length of the cutter head according to the geological conditions and the target recovery rate of coal seam.It is found that the annual coal production linearly increased with the increasing cutter head advancing speed.Furthermore, a suitable drilling speed parameter and the utilization of the high-pressure water jet are both important to the increase of coal production.

Keywords

• steep-inclined coal seam
• fluidized mining
• reverse-circulated mining
• parallel excavating and drilling method