THREE-DIMENSIONAL MODELING OF AIR-BORNE DUST CLOUD PROPAGATION BEYOND SURFACE MINE BOUNDARIES DURING LARGE-SCALE BLASTING

Wind transport of an air-borne dust cloud in the atmospheric boundary layer in the neighborhood area of a surface mine is analyzed by numerical solution of the Navier–Stokes equations in their full form for a compressible liquid and in a subsonic flow approximation. The dust source is a large-scale blast at a total mass of  \(\sim\) 100 g of TNT at a depth of 250 m in the pitwall rock mass. The calculations take into account a portion of dust raised above ground surface by blasting. The size of the surface areas of air-borne dust concentrations above maximal allowable values is estimated. The relationship of this size and the wind direction–pitwall angle  \(\alpha\)  is analyzed. The maximal distance between the pitwall and the area of dust concentration above MAV is 3 km. The exposure duration at the fixed point on ground surface is independent of the angle  \(\alpha\)  and ranges from a few minutes at a distance of 500 m from the blast center to a dozen minutes at a distance of 3 km.