During the explosion of borehole charges in underground workings at the initial moment of the explosion (before the beginning of rock detachment) the explosion products and the stemming from the borehole are ejected. The main reason for the formation of shock air waves is expanding gaseous products of the explosion. In the initial stage of expansion of the products of the explosion, the wave front has the shape of a hemisphere, somewhat distorted toward the axis of the borehole due to the axial dispersion of the products of the explosion and the stemming. In the subsequent stages, as the wave front interacts with the walls of the excavation, a plane wave is formed. Its intensity is determined by the energy that the expanding products of the explosion impart to the air.