THE OPTIMAL LENGTH OF THE SEALING MATERIAL AS THE MAIN INDEX OF REGULATING THE MASSIVE EXPLOSION ACTIVITIES

Abstract

The main method of preparing the extraction of rocks in open-pit mines are the explosion activities. However, mass explosions in open pits are accompanied by a large amount of dust and gas. Blasting the borehole charge, the product of the instant gas formation of explosive charge in the borehole creates tremendous pressure (approximately 10⁴ MPa) which is significantly greater than the tensile strength of the rock (about 10² MPa), and the impact of the gas pressure results in an uncontrolled flight of the blasted rock, a large output of extra-sized fractions, and the effect of the air and seismic waves and the volume of dust and gas. Mass explosions in open fields are accompanied by a seismic impact on the field and adjacent territories, throwing out individual parts of the exploded rock, and intense gas and dust emissions. Thus for instance, in case of blasting one ton of explosive material (EM), the amount of the dust formed in the size from 0 to 150 microns, depending on the parameters of the explosion, ranges from 40 to 250 kg. While, the amount of EM used in metal deposits reaches tens of thousands of tons. This creates the need to simultaneously solve technological and environmental problems. The technological problems require that the working site of an open-pit mine have a collapse of the blasted rock mass with the necessary fragmentation. Environmental problems require reducing dust emissions into the atmosphere of the mine.

It has been shown that the optimal length of the sealing material reduces the amount of powder and gas released into the atmosphere and increases the duration of the active explosive action in the rock mass.

By analytical calculations, the kinematic parameters of the sealant flight and the value of its length were determined depending on the main parameters of the explosion and the power of the explosive:

Based on the selection of the optimal length of the sealant, the rational parameters of the explosion have been determined which allows to solve the technological and ecological problems of the explosion.