Section 1 includes an analysis of the current assortment of permissive explosives (PE) in Ukraine and the prospects for improving the PE composition. It has been established that the PE development and improvement is an important urgent problem aimed at improving safety during blasting process. The disadvantages of regular PE were considered for a better understanding of the PE use issue.
This section also presents an analysis of the research results by Makeevka Research Institute for Mining Safety, Donbass Scientific Research and Design Coal Institute, Donetsk Scientific Research Coal Institute, Dondiprovuhlemash Donetsk State Research, Design and Experiment Institute for Complex Mine Mechanization State Enterprise , State Scientific and Research Institute of Organization and Mechanization of Mining, Institute of Geotechnical Mechanics named by N. Poljakov of National Academy of Sciences of Ukraine that described the causes of methane-air mixture (MAM) and dust-air mixture (DAM) ignition in hazardous mine workings. As the result
of the combustion process experience analysis, it was found that permissible TNT-containing explosives have a high tendency to burn out and a high combustion pressure. In addition, PE used in Ukraine, are environmentally hazardous and contain toxic substances such as TNT and nitrate ester.
It was found that the further PE development and improvement in Ukraine should be based on the EE experience. Moreover, it is necessary to consider the experience of the PE use in the world. These explosives do not contain brisant explosives (TNT and nitroglycerin), unlike ammonite and carbonite. Ukraine has accumulated considerable experience in the technology development for the production of EE that are used in open-pit mining and that can be used in the permissible EE development. There are no permissible EE available in Ukraine, but work in this direction is at the stage of scientific research. The characteristics of permissible poremite made in Russia and emulinite produced in Poland were given as an example. The advantages of permissible EE comparing with packaged TNT-containing PE are given.
The experience of achieving permissible properties for EE was considered. Based on the references, it was found that the best permissible properties of explosives occur when NaCl obtained by ion exchange reaction is added to the composition of explosives as a flame retardant.
Considering the research on the use of sensitizers, it is established that sensitization of permissible EE must be conducted using microspheres.
The theoretical research on properties and characteristics of spermissible EE is presented in the section 2.
The permissible EE of IV class composition was selected in the course of research. The emulsion composition of the was determined as the main component for development of the basic permissible EE. The emulsion consisted of an oxidizing phase (OP) that included ammonium nitrate, sodium nitrate, water and of a combustible phase (СP) that included a mixture of emulsifier and industrial oil. Glass microspheres were selected as sensitizers.
Two methods of ion exchange salt injection were used during permissible EE composition calculation. The first method involved injection of NaNO3 and NH4Cl ion
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exchange salts into the EE emulsion base. The second method involved injection of NaNO3 and NH4Cl ion exchange salts with the addition of KCl to the EE emulsion base. Thermochemical calculations of two compositions were conducted using the Lethal force program. After comparing the obtained thermochemical parameters (explosion heat, explosion temperature, total gas volume, oxygen balance (OB)) between the two compounds and with similar thermochemical parameters of standard TNT-containing explosives, the proper permissible EE composition was selected. It contains NaNO3 that interacts with NH4Cl to form the required amount of NaCl flame retardant. The explosion heat of the selected formulation of permissible EE composition is 2305 kJ/kg, OB is -0.67% and, according to these indicators, is larger thе TNT-containing PE.
