Using the methods to calculate parameters of drilling and blasting operations for emulsion explosives

Abstract

Mathematical modelling of rock mass breaking using blasting has been applied to obtain formulas for the calculation of crush zone radii, intensive fragmentation, and crack formation around the charging cavity in the structure, diameter of the charging cavity, diameter of the charge itself, detonation characteristics of an explosive, boundaries of the rock strength, rock mass jointing, and mineral compression under the effect of rock pressure. The methods have been developed to calculate parameters of drilling and blasting operations (DBOs) while driving the mine workings based upon the idea of the arrangement of blastholes in terms of areas they occupy in a fore-breast as well as upon their location relative to break-off outline. Stage one of the methods involves calculating and designing burn cuts where a distance between blastholes is determined with the help of a fragmentation zone radius. Stage two means calculation of both specific and total explosion consumption per borehole bottom, line of least resistance (LLR) for a borehole in terms of intensive fragmentation, areas of borehole groups, borehole number, analytical and actual distance between boreholes, actual charge amount per borehole, and actual specific and the total explosive (E) consumption per borehole bottom. The methods have been tested in the operating ore mine while driving a mine working. Emulsion explosive (EE) Ukrayinit-PP-2 (Україніт-ПП-2) has been applied. The developed methods have been used to calculate DBOs parameters for the explosive. Trial blasts demonstrated the good firing of a borehole bottom and uniform ore fragmentation; a high coefficient of borehole use has been supported.