The article describes problems of blasting operations carried out at an industrial scale using ammonia-nitrate explosives. Based on experimental studies conducted by the authors, it was determined that for use in mining enterprises in Mongolia, primarily in coal mines, the most rational and effective explosives are mixed ones based on ammonium nitrate in the solid state with various liquid as well as solid dispersed fuels additives - ANFO mixtures. The temperature boundaries for the phase transitions of ammonium nitrate in open areas for the period of three months for different humidity values have been determined. The indicators of oil absorption are identified depending on the cycle of phase transitions for ammonium nitrate.
Results are presented on the effect of firing rate on pressure pulse in charge camera and fracture stress during spalling. Results are presented of comparative calculations using the equations of autocatalytic reactions of firing rates and escape of reaction products for the system of sodium chlorate - polythene (propylene) in pipe shape. Dependences are obtained of firing rate on concentration of gas generating mixture, its density, components size distribution and cartridge case size. Experimental and computational data were used to consider the conditions of firing turning into explosion for compositions based on sodium chlorate and hydrocarbons in layered and powdered systems. The relation is retrieved between the technological parameters of mining activities (blast hole to blast hole distance, blast hole diameter, depth of cartridge placement) and specific cartridge consumption along the spalling line with gas generators going off.
The method of calculating the net hole charges, based on a combination of fracture zones. The mechanisms of energy transfer and change of stress, depending on the material filling the cracks in the explosive destruction of the fractured rocks.
The article considers the problem of size distribution of grain-size composition of the blasted rock mass, rock fragments blasted rock mass and rock blockiness. The logarithmic-normal distribution law is laid down for all blasted granite mass products. It was proved, that logarithmic variance of logarithmic normal distribution law of the fractured rock mass fragments’ distribution is a structural invariant on the level of statistical universe of the block and fragments.
In exploitation of deep open-pit one of the main problems is increasing stability pit wall during making it in final position. As is generally known, to provide over contour massive in safety is used one of widespread blasting method – the pre-split blasting. In given work is proposed to use gel explosive Gelpor GP-2У to make a quality reflection crack for Kostomuksha ore open pit geological structure. Were made a calculation of basic parameters in pre-blasting method with using gel explosive Gelpor GP-2У and given estimation of calculation result with experimental data, using on Kostomuksha ore open pi in pre-split blasting.
Experimental studies of the granulometric composition of rock mass obtained as a result of blasting and impact destruction confirmed good convergence of experimental data with the theoretical log-normal distribution law. It is proved that the logarithmic dispersion of the lognormal law of distribution of pieces of the fragmented rock massif is a structural invariant at the level of the statistical set of blocks and pieces. The model of destruction of polymineral rocks by explosion energy is proposed.
Sulfide dust explosions and hazardous sulfur gas emissions are still an urgent problem in blasting operations at copper deposits. In this paper, the solution to this problem is proposed by using an optimized explosive structure. Theoretical analysis of the main characteristics of explosive transformation of the proposed structures depending on the physical and chemical properties and the content of safety additives in the explosive is carried out. The obtained graphical dependences allow a differentiated approach to the choice of the explosive structure, providing effective explosion performance and proper safety of blasting operations.
Представлены результаты исследований в атмосферных условиях и в манометрической бомбе скорости горения композиций на основе хлората натрия с полиэтиленом, а также натурных испытаний газогенераторов, изготовленных на основе этих композиций при отбойке гранитных блоков и дробления валунов.
The subject of the research was the state of safety of buildings of engineering structures and the environment, located in the zone of influence of mining operations, under the influence of seismic and shock air waves from the production of blasting operations. In the research work full-scale measurements of arguments of seismic and shock air waves in the requirements of production of mass explosions and lump crushing at different blasting schemes both on mining and geological and meteorological requirements were carried out. Optimal requirements to the organization and production of blasting operations are proposed.
The object of the research is the state of safety of buildings of engineering structures and the environment, located in the zone of influence of mining operations under the influence of seismic blasting and shock air waves from blasting operations. Full-scale measurements of parameters of seismic blasting and shock air waves during mass blasting and oversize crushing with various blasting schemes in various mining and geological and meteorological conditions have been carried out. Optimal conditions for organization and production of blasting operations are proposed.
The formation of the structure of the chipping zone can be investigated using the method proposed by B.V. Zamyshlyaev to determine the structure of the cavitation layer during explosion of explosives in water near the free surface. The method is based on the use of the laws of disintegration of an arbitrary discontinuity during the interaction of a stress wave with a free surface. As a result of the interaction, a shock wave will propagate in the air, and a rarefaction wave will propagate along the condensed medium from the interface toward the explosion chamber. The maximum tensile stress in the rarefaction wave is determined by the method of mirroring the explosion source with the introduction of an imaginary charge.
Conducting excavations and clearing works on colliery ores in a number of cases is accompanied by sulfide dust explosions, which release a large amount of sulfur dioxide gas, significantly exceeding the allowable by standards, which leads to increased airing time and long downtime of faces, and sometimes to severe poisoning of people. Release of sulfur dioxide gas occurs in conventional faces, not dangerous in terms of sulfide dust explosion, due to its low ignition temperature (about 400-450°С). To improve the safety of blasting operations it is necessary to study the kinetics of ignition and explosion of sulfide dust.
To calculate the parameters of drilling and blasting operations for explosive destruction of rocks, empirical dependences or relations based only on the action of stress waves are used. It is known, however, that at the quasi-static stage of the explosion there is additional destruction of rocks. It is manifested both in the secondary crushing of pieces in the fracture zone and in the increase in the size of this zone. Qualitatively, these effects are known and used, in particular, in the creation of various types of faces in the mouths of boreholes and wells, increasing the duration of the quasi-static stage of the explosion. However, the physical and mechanical processes of additional fracture at the quasi-static stage of the explosion have been studied much less than at the wave stage.
В современной технологии взрывной отбойки при проведении горных выработок все большее применение находят параллельные врубы, принцип работы которых заключается в том, что при взрыве шпуровых зарядов происходит разрушение породной перемычки между заряженными шпурами и холостой скважиной, в результате чего образуется врубовая цилиндрическая полость большей глубины ...
