Discussion on test depth of initial speed from borehole gas emission

With an analysis on influence factor of gas emission initial speed in the borehole and the relationship of the stress distribution status in the front of the coal mining face, the paper showed that the test depth of the gas emission speed in the borehole should be through the seam pressure released zone into a plastic ultra stress district of a stress concentrated zone. As for the seams with different mine geological conditions, a site measurement should be made for the area of the seam pressure released zone and the plastic stress district in the front of the coal mining face in order to correctly measure the initial rational test depth of the gas emission speed in the borehole.