New method for determining parameters of drilling and blasting for horizontal and inclined mine workings

Abstract

Purpose. Development of a new methodology for calculating the parameters of drilling and blasting (D&B) for horizontal and inclined mine workings, taking into account the pressure of the explosion products, the compressive strength of rocks, their structural structure, fracturing and compaction under the action of rock pressure. The methodology of research. Using the well-known laws of the theory of elasticity and the main provisions of the quasi-static-wave hypothesis of the mechanism of destruction of a solid medium by an explosion, a method has been developed for determining the D&B parameters for excavating, which is based on the principle of placing groups of blast-holes in the areas they occupy in the working face and their location behind outside the fender circuits. To establish the suitability of the developed new methodology for calculating the parameters of the D&B, it was tested in the conditions of a real object. Findings. A methodology has been developed for calculating the parameters of the D&B in the excavating, which is based on the principle of placing groups of blast-holes in the areas they occupy in the working face and their location behind outside the fender circuits. The first stage of the methodology includes the calculation and design of straight cuts, the distance between the blast-holes in which is determined by the radius of the crush zone. The second stage of the methodology includes the calculation of: specific and total costs of explosive (EX) per slaughter, the value of the line of least resistance (LLR) for the blast-hole along the radius of the zone of intensive grinding, the areas of groups of holes, the number of blast-holes, the calculated and actual distance between the blast-holes, the actual value of the charge per blast-hole, actual specific and total costs of EX for working face. Approbation of the developed methodology was carried out in the conditions of an operating ore mine during excavating using a bulk emulsion explosive (EЕ) Ukrainit-PP-2, for which the D&B parameters were calculated according to the developed method. On the basis of test blasts, good results were obtained for blasting the bottom of the working, uniform ore crushing and a high utilization rate of blast-holes. The originality. The parameters of the location of blast-holes in the working face are implemented according to the power-law pattern of change in the LLR depending on the diameter of the blast-hole, the pressure of the explosion products, the compressive strength of the rocks, their structural structure, fracturing and compaction under the action of rock pressure. Practical implications. The developed method for determining the D&B parameters for horizontal and inclined mine workings makes it possible to rationalize the uniform arrangement of blast-holes in the working face and to save resources when performing drivage up to 18%.