MANAGEMENT OF CONTOUR BLASTING PARAMETERS FOR BOREHOLE CHARGES IN OPEN-PIT MINES

Abstract

A scientifically substantiated engineering methodology has been developed to determine the parameters of contour borehole charges for creating pre-split cracks during bench sloping and establishing final pit walls under dry and water-bearing conditions. Parameters were determined for three types of packaged explosives – Nitronit P, granular-powder Granulite RP, and ZKV-B – in dry boreholes, based on the condition of obtaining a pre-split crack with the same geometric dimensions as those produced by contour charges of Ammonite 6ZhV, which was used as the calculation reference.
Calculated values for contour blasting charge parameters were obtained to produce pre-split cracks with specified dimensions ( )  using low-density ammonium nitrate explosives corresponding to rocks with similar physico-technical characteristics. A graph showing the dependence of the linear contour charge diameter  and the spacing between charges  on the applied borehole diameter  is presented for the explosive types under consideration. The technology for forming contour linear detonating charges from granular-powder explosives in flexible corrugated HDPE pipes is described.