METHOD FOR CONDUCTING OF DRILLING AND BLASTING OPERATIONS Russian patent published in 2002 - IPC

FIELD: mining industry. SUBSTANCE: the method consists in drilling of a borehole, formation of a combination charge column from the borehole bottom by stratified alternation of commercial explosive and ammonium nitrate, the layers of ammonium nitrate are placed between the layers of commercial explosive; live primers are installed in the combination charge layers in such a way that, as a result of their actuation, the same time of detonation of each layer located between the center of the live primer and the plane of encounter of detonation waves or the end faces of the combination charge is ensured; proceeding from the condition of equality of the times of detonation of the layers the height of each layer of ammonium nitrate and commercial explosive making up the combination charge is calculated by the formulas given in the description at multiple-point and alternative initiation. EFFECT: enhanced efficiency of crushing of the rock bulk due enhanced efficiency of blast and reduced yield of outsized lumpy fractions. 9 cl, 16 dwg