The article presents an assessment of the influence of aluminium granules content on selected detonation parameters of a chemically sensitised bulk emulsion explosive. The analysis covered determination of relative explosive strength using a ballistic mortar and Trauzl blocks, free field air blast tests and detonation velocity measurements. Five types of emulsion explosives with differing aluminium content were tested at loadings of 0, 1, 3, 5 and 7%.

Abstract:One of the main parameters describing the properties of explosives is the velocity of detonation, which can be defined as the propagation speed of the chemical reaction zone in the detonating explosive. The detonation velocity of an explosive depends on many parameters, such as the material's density or diameter and the shell of an explosive, plus the degree of crystal fragmentation, the initiation method and the content of particular components. The effectiveness of blasting work in underground mines depends primarily on the proper selection of the hole diameter, hole length, the distance between the holes and the delays of the detonators used. This article presents the results of studies investigating the influence of the diameter of a bulk emulsion explosive charge on the detonation velocity using a MicroTrap TM VOD/Data Recorder manufactured by MREL, Canada. The underground tests were developed in the "Polkowice-Sieroszowice" copper mine in Poland.

One of the elements of enhanced safety of mechanically loaded emulsion explosives is the loss of its explosive properties after a certain period of time, without reference to the particular research. The manufacturer described this time for approximately 48 hours from the time of its charging to the blasting holes with a gas sensitized product. Under regular conditions of mining works, this time is absolutely sufficient for safe mining operations. In practice, some unforeseeable situations may occur that the charged explosive is not fired within the prescribed period of time. The aim of the study was to verify the knowledge regarding the behavior of mechanically loaded emulsion explosives used in Polish underground copper mines by tracking the changes of detonation velocity over time. The subject of research was Emulinit 8L emulsion explosive manufactured by NITROERG from Bieruń, Poland. The measurements were provided using a MicroTrap™ VOD/Data Recorder, which allows for continuous measurement of the detonation velocity of explosives.

In this workcylinder testswere performed for two emulsion explosives (Emulinit 8L and Emulinit GM1) used in the mining industry. Based on the results of the tests, the detonation pressure and energy of these explosives were estimated. The detonation characteristics obtained, the profile of the expanding copper tube and the results of the numerical simulation enabled the constants in the JWL(Jones-Wilkins-Lee) equation of state to be determine for the detonation products of these two explosives.

Bulk emulsion explosives, although they are very convenient and safe to use, also have disadvantages, with the main one being the relatively low power in relation to cartridged emulsion explosives or classic nitroesters (e.g., dynamites). Therefore, materials of this type currently have only limited use. In addition, these materials are characterized by the variability of blasting parameters over time from loading into the blasthole, which is closely dependent on the utilised mining method of the mine, which makes it difficult to precisely control the fragmentation. The industry is trying to respond to the demand for bulk emulsion explosives with increased energy and improved parameter stability, but so far it has not been possible to do so in a safe and effective way. Methods of improving blasting parameters mainly rely on additives to oxidant solutions during production, which creates additional risks at the production stage, as it involves handling hot and concentrated ammonium nitrate solutions, for which there are known cases of uncontrolled decomposition of such solutions, even leading to an explosion. This paper presents a method of improving the thermodynamic parameters and the stability of the sensitization reaction without the need for changes in the oxidant solution.