NUMERICAL SIMULATION OF THE ATMOSPHERIC EVOLUTION OF DUST PRODUCED BY EXPLOSIONS IN BOREHOLES OF A MINING QUARRY

Abstract

A numerical model for calculating explosive detonation in boreholes is described. The model provides for the possibility of converting ejecta from the explosion crater into discrete particles (dust and stones) and calculating the motion of these condensed particles and their interaction with the gas flow within the framework of the equations of motion of multiphase media. The results of the calculation of 1000 kg TNT explosions in several boreholes 15 m deep are presented. These calculations demonstrate the formation and evolution of a gas and dust cloud, the change in the mass of particles of different sizes in the air with time, and their spatial distribution. A numerical analysis of the behavior of a gas and dust cloud in the wind field after completion of its rise was carried out, and the first approximation of dependence of the surface concentration of fine particles on time was obtained at distances up to several kilometers from the quarry wall. According to the calculations, the excess of the maximum permissible concentration of suspended particles in the atmosphere at downwind distances exceeding 500 m from the pit will not be achieved under the conditions of the considered problem