Optimal parameters for drilling explosions when developing coal deposits by open-pit method

¹ Saint-Petersburg Mining University, 2, 21 Line V.O., 199002, St. Petersburg, Russia
² Ukhta State Technical University, 13, Pervomayskaya St., 169300, Ukhta, Republic of Komi, Russia

^* Corresponding author: afan_@mail.ru

Abstract

The article discusses two deposits of coal mining by the open method. The «Zarechnyi» open-pit is located in Kuzbass, and the «Vostochno-Beiskyi» open-pit is in Khakassia. The main parameters of drilling and blasting operations are given, the geological structure of the deposits is described. The methods of calculating the specific charge, the diameter of the wells and the grid of wells are considered. Blasting operations are an integral part of the mining process. The cost of finished products and the quality of raw materials supplied to the crushing and screening complexes depend on the results of blasting of the rock mass. The currently used retractable blasting technologies, produced according to standard designs, lead to large energy losses during the explosion, as well as to the output of the oversized fraction, which in turn leads to downtime, reduced productivity and breakdown of transport and loading equipment. The paper substantiates the parameters of drilling and blasting operations taking into account the physical processes occurring in the explosive cavity and during the stress wave propagation in the rock mass. Parameters of detonation products are estimated on the basis of shock-wave compression, the refraction of a detonation wave into a rock based on the theory of the breakdown of an arbitrary discontinuity, the stress wave propagation taking into account polymorphic transformations and dissipation energy. Recommendations for reducing the specific charge of explosives, for choosing the diameter of the borehole charge and the grid of wells are proposed.