Emulsion Explosives Research Articles

Implementation and Verification of Effectiveness of Bulk Emulsion Explosive with Improved Energetic Parameters in an Underground Mine Environment

Explosives are commonly used in the mining industry to extract minerals from hard rock deposits. Therefore, an efficient explosive should ensure that the appropriate blast outcome is achieved, taking into account the desired rock-breaking parameters and the costs of drilling and blasting works. Depending on the type of deposit and follow-up processes, a proper blast result may be characterized by fragmentation, muckpile shape, overbreaks, etc. Industry has struggled to respond to the demand for bulk emulsion explosives with improved energetic parameters, having so far been unable to do so safely, effectively, and cost-efficiently. Methods of improving blasting parameters mainly rely on introducing a variety of additives to the emulsion explosive formulation during production, which creates additional hazards at that stage. Alternative, safe methods of achieving an improved energetic performance of emulsion explosives are, therefore, highly desirable. This paper is focused on one such proposed method as a continuation of previous research works and the performance of a novel bulk emulsion formulation under real mining conditions during the firing of mine faces is described. The tests included density measurements over time, measurements of impact and friction sensitivity, measurements of the detonation velocity in blastholes, determination of brisance via Hess test, and analysis of rock fragmentation. Results were compared with those obtained with a commercially available bulk emulsion explosive, highlighting that the performance improvement achieved by the proposed emulsion modification method is not limited to artificial test conditions, but translates well into actual application conditions.

Numerical modeling of charge diameter effect on detonation properties of emulsion explosives using Wood-Kirkwood detonation model

ABSTRACT Emulsion explosives exhibit strong nonideal detonation behavior, which provides a challenge for accurate numerical modeling. We present a nonideal detonation model based on the Wood–Kirkwood detonation theory and EXPLO5, capable of modeling the effect of the charge diameter on steady-state detonation velocity. The elements of the model are calibrated based on experimental data for four different emulsion explosives. It was demonstrated that both simple pressure-dependent and Kirby and Chan’s two-step reaction rate models can satisfactorily reproduce the detonation velocity–charge diameter data of unconfined charges. In addition, the reaction rate parameters are found to be a function of the density of explosives.

Emulsion Explosives: A Tutorial Review and Highlight of Recent Progress.

Emulsion explosives (EE) have been commercially available in various forms for over 50 years. Over this period, the popularity and production technology of this class of energetic materials have been developing constantly. Despite this rapid rise to prominence and, in some applications, prevalence over traditional energetic materials, remarkably little information is available on the physicochemical and energetic properties of these materials and factors affecting those properties. This work is dedicated to presenting the fundamental information relevant to the features, properties and applications of EEs, while highlighting the most significant recent progress pertaining to those materials. Particular emphasis has been given to providing information about the types, composition, modifications and detonation parameters of EEs, as well as to highlighting the less obvious, emerging applications of EEs.

Blast Effects of a Shear Thickening Fluid-Based Stemming Material

The Trauzl test is widely used to measure the explosive power of a substance by determining the volume increase produced by the detonation of a tested explosive charge in the cavity of a lead block with defined quality and size. In this study, the Trauzl lead block test and a high-speed 3D digital image correlation (3D-DIC) system were used to evaluate the effect of stemming on a blast hole. The blasting experiments were conducted with emulsion explosives. The stemming materials adopted in this study were sand, aggregate, and shear thickening fluid (STF)-based stemming materials. The results of the blasting experiments and numerical analysis showed that the expansion rate of the lead block was most affected by STF-based materials, followed by aggregates and sand stemming. Furthermore, the displacement and surface strain on the block were the highest in the experimental case using STF-based stemming materials. The STF-based stemming material developed in this study in open pit mining or various blasting constructions is expected to increase rock fragment efficiency, compared to that of general blasting stemming methods, and reduce blasting vibration by decreasing the amount of explosive per blast hole used for blasting.

Initiation of Detonation of an Emulsion Explosive by Impact of a Thin Plate

Initiation of Detonation of an Emulsion Explosive by Impact of a Thin Plate

Исследования детонационных характеристик эмульсионных взрывчатых веществ, применяемых на железорудных карьерах

The paper outlines the main trends in the development of blasting operations used in iron ore mining. It is pointed out that due to the tendency to raise the weight of blast charges, an increasing negative effect of the seismic blast action is observed on the surrounding rock masses and protected facilities. In order to identify efficient ways to reduce seismic impact on the final pit outline and the protected facilities, a set of field tests was performed on the detonation characteristics of emulsion explosives for the conditions of iron ore open pits. The paper demonstrates that petering-out of detonation is observed for the extended charge of explosives. Analysis of causes for the detonation failure showed that it can be related to non-observance of the technology to charge watered boreholes, failures to meet the technological process when manufacturing the emulsion explosivuseful minerals, explosives, protected facilities, seismic action, detonation, emulsion explosives, charge, deflagration, booster, primer, environmentes, blast hole collapses caused by premature firing of the neighboring holes that have bigger delays. Analysis of the research results into the detonation characteristics of emulsion explosives showed that the probability of shifting from detonation to a low-velocity mode or deflagration is related to the length of the emulsion charge, the distance from the booster and probability is increasing at the lower (reverse) method of firing the charge. It is concluded that in order to increase the reliability of detonation of the emulsion explosives it is required to minimize the length of the emulsion part of the charge and to use combined firing methods of the blast charges.

Examination of density and detonation velocity of emulsion explosives

Examination of density and detonation velocity of emulsion explosives

Thermal Safety Analysis of On-Site Emulsion Explosives Mixed with Waste Engine Oil

The study of the thermal safety of emulsion explosives mixed with waste engine oil is very important for the safety of these types of explosives used in mine blasting. In order to study the thermal safety of emulsion explosives mixed with waste engine oil, thermal safety tests were carried out using a Differential Scanning Calorimeter (DSC), non-isothermal kinetics, and the Flynn–Wall–Ozawa method. The results show that the minor particle impurities in the filtered waste engine oil are mainly combustibles; after adding different amounts of waste engine oil, the activation energy of the emulsion matrix decreases from 110.33 kJ/mol to 75.39 kJ/mol, 74.50 kJ/mol, and 82.23 kJ/mol, and the critical temperature for thermal explosion changes from 194.16 °C to 169.73 °C, 227.47 °C, and 208.78 °C. The addition of waste engine oil reduces the activation energy of emulsion explosives. The waste engine oil is negatively correlated with the activation energy and the thermal explosion reaction temperature of emulsion explosives, and the correlation coefficient is −0.686 and −0.333. The emulsifier is positively correlated with the critical temperature of thermal explosion of emulsion explosives, and the correlation coefficient is 0.251. The small particles in the waste engine oil create a hot spot in the emulsion explosives, which reduces the thermal safety of the emulsion explosives mixed with waste engine oil. The emulsifier reduces the droplet size of the emulsion explosive, improves the oil-water interface strength, and improves the thermal safety of the emulsion explosives mixed with waste engine oil. The thermal safety of emulsion explosives mixed with waste engine oil can be improved by reducing the proportion of the sensitizer and increasing the proportion of the emulsifier.

Novel Sensitizing Agent Formulation for Bulk Emulsion Explosives with Improved Energetic Parameters.

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.

Способ повышения качества подготовки пород к выемке при использовании эмульсионных взрывчатых веществ на карьерах с высокими уступами

Increasing the production capacity of open-pit and strip mines while ensuring the efficiency of the mining enterprise can be achieved through enhancing the quality of rock preparation prior to excavation. The use of emulsion explosives and the transition to the high-bench technology can reduce the cost of mining operations by optimizing the drilling and blasting parameters. The article reviews methods to improve the efficiency of rock preparation for extraction based on the applicable scientific and methodological principles and it proposes a method to regulate the density of emulsion explosives. Schemes are presented for calculation of drilling and blasting parameters when implementing technical measures aimed at improving the blasting quality through rock preparation for extraction in conditions of overburden and mining operations with bench height of 15 m and higher. Parameters of drilling and blasting operations on high benches are justified with differentiation of the charge density along the length of the blast hole by controlling the delivery of the gas-generating additive. A simulation has been performed and the results of pilot tests of the emulsion explosive charge density control at the Ural deposits are presented.

DETERMINATION OF DETONATION FRONT CURVATURE RADIUS OF ANFO EXPLOSIVES AND ITS IMPORTANCE IN NUMERICAL MODELLING OF DETONATION WITH THE WOOD-KIRKWOOD MODEL

Nitratebased commercial explosives, such as ANFO (ammonium nitrate/fuel oil mixture) and emulsion explosives, are characterized by a curved detonation front. The curvature is directly related to the rate of radial expansion of detonation products in the detonation driving zone and the rate of chemical reactions, and it is one of the characteristics of nonideal explosives. The detonation theories used to model the nonideal behaviour of explosives require both reaction rate and rate of radial expansion to be known/specified as input data. Unfortunately, neither can be measured and what is mostly used is a link between these rates and parameters which can be more easily measured. In this paper, the Wood-Kirkwood approach of determination of radial expansion through the radius of detonation front curvature and the electro-optical technique for experimental determination of detonation front curvature of ANFO explosives is applied. It was shown that an experimentally determined radius of detonation front curvature vs charge diameter, incorporated in the Wood-Kirkwood detonation theory, can satisfactorily reproduce experimental detonation velocity-charge diameter data for ANFO explosives, especially when the pressure-based reaction rate law is also calibrated (D=1.3 and k=0.06 1/(μs/GPaD)).

Influence of an Aluminum Additive on the Detonation Temperature of an Emulsion Explosive

Influence of an Aluminum Additive on the Detonation Temperature of an Emulsion Explosive

Initiation of Detonation of an Emulsion Explosive by Impact of a Thin Plate

Initiation of Detonation of an Emulsion Explosive by Impact of a Thin Plate

Rapid Prediction of Effect of Ferrous Iron on the Stability of Emulsion Explosives Matrix

Designing an emulsified matrix formulation in the laboratory, the ratios of the emulsifier span-80 and T-152 were 1:0, 2:1, 1:2, 0:1 respectively. Then the preparation was added by 0.04% Fe2+ impurities emulsion matrix. Based on the water-soluble test method, we used ultrasonic instrument to focus on emulsion matrix containing Fe2+ impurities. The results show that the crystallization amount of emulsion matrix by adding Fe2+ is more than that of not adding Fe2+ .Impurities Fe2+ has damaging effects on the stability of its interface membrane. At the same time, ultrasound can accelerate the speed of demulsification of emulsion matrix. As composite emulsifiers span-80: T-152=1:2, the stability of emulsion matrix is the best.

Peculiarity for the stability of three different emulsion explosives

An investigation was performed into the stability of three emulsion explosives, namely bulk, packaged and powdery emulsion explosive. The dynamic stability is crucial for bulk emulsion explosive, and the experimental results show that it will possibly achieve both good dynamic stability and fluidity when polyisobutene succinic anhydride (PIBSA) based emulsifiers, such as PIBSA-DTEA, PIBSA-TEA and PIBSA-STEA etc, used alone in preparing explosive. Opposite with that, the long-term storage stability is much more important for packaged emulsion explosive. In several PIBSA based emulsifiers, polyisobutene succinimide (PIBSI) is more suitable for improving the stability of packaged emulsion explosive. Moreover, the stability also can be improved through rising the toughness of oil film, like adding a certain amount of microcrystalline wax. The caking of ammonium nitrate (AN) crystals with time is the key reason, which decreasing the stability of powdery emulsion explosive. The caking phenomenon will be weakened with the addition of rosin because the softened rosin can allow the repair of damaged oil film and prevent AN crystals breaking the oil film. Besides that, adding potassium nitrate to AN solution or a certain amount of talcum powder also can effectively improve the stability.

Совершенствование термопарного метода для испытаний энергоемких эмульсий на совместимость с сульфидными рудами

The results are presented concerning improving the thermostatic method for studying the chemical compatibility of modern industrial emulsion explosives based on the ammonium nitrate with surrounding materials, the increased reactivity of which can lead to spontaneous ignition and even explosion. An assessment of the compatibility of emulsion explosives with sulphide ores was conducted using an original thermocouple methodology developed at the D. Mendeleyev University of Chemical Technology of Russia, fixation of the thermal effects of the interaction of shell-free explosives based on the ammonium nitrate with sulfide minerals. Improved thermocouple method allows to determine chemical compatibility of the industrial explosives with the reactive rocks. It is distinguished by the possibility of continuous recording of the thermocouple measurements during tests using an oscilloscope and combines the reliability of the results with small laboratory weights of the test samples (no more than 20 g, which ensures safety testing). Temperature measurement accuracy is ± 2 °С. It is concluded that the method used is able to identify the cases of the most dangerous interaction from the practice point of view using the emulsion explosives when the pyrite content in the ore exceeds 85 %. The results of experiments on the applicability of thermocouple measurements to testing low-activity rocks, highly reactive pyrite ores, mixed sulfide ores of medium activity, as well as on the identification of the main regularities of heat release during the interaction of emulsion explosives with the sulfide ores are considered.

Effect of Aluminum Additive on the Detonation Velocity and Acceleration Ability of an Emulsion Explosive

Effect of Aluminum Additive on the Detonation Velocity and Acceleration Ability of an Emulsion Explosive

Explosion temperature mapping of emulsion explosives containing TiH2 powders with the two-color pyrometer technique

In the study, the two-color pyrometer technique was used to measure the transient temperature field of emulsion explosives with different contents of TiH2 powders. The experimental results showed that the introduction of TiH2 powders could significantly increase the explosion temperature and fireball duration of emulsion explosive. When emulsion explosives were ignited, the average explosion temperature of pure emulsion explosive continuously decreased while emulsion explosives added with TiH2 powders increased at first and then decreased. When the content of TiH2 powders was 6 mass%, the explosion average temperature reached its maximum value of 3095 K, increasing by 43.7% as compared with that of pure emulsion explosive. In addition, the results of air blast experiment and explosion heat test showed that the variation trends of shock wave parameters, explosion heat and theoretical explosion temperature of emulsion explosives with different contents of TiH2 powders were basically consistent with that of explosion temperature measured by the two-color pyrometer technique. In conclusion, the two-color pyrometer technique would be conducive to the formula design of emulsion explosive by understanding the explosion temperature characteristics.

Theft-Safe Explosive Mixtures Based on Hydrogen Peroxide: Study of Properties and Built-In Self-Deactivation Kinetics.

The current focus on both environmental and general safety is an important issue in the field of explosives. As such, environmentally-friendly explosives, based on hydrogen peroxide (HTP) as an oxidising agent, are of significant interest. These explosives can be designed to undergo self-deactivation, denying access to them by any unlawful third parties that may attempt scavenging blasting sites for any residual energetic materials. Such deactivation also improves blasting safety, as, after a set time, misfired charges no longer pose any explosive threat. In this work, we have designed HTP-based explosive formulations that undergo deactivation after approximately 12 h. To this effect, Al powders were used both as fuels and HTP decomposition promoters. The shock wave parameters and ability to perform mechanical work of the proposed explosive formulations are comparable to those of dynamites and bulk emulsion explosives, and the details of the changes of these parameters over time are also reported.

Обоснование технологий и средств для проведения горизонтальных горных выработок с использованием эмульсионных взрывчатых веществ

Обоснование технологий и средств для проведения горизонтальных горных выработок с использованием эмульсионных взрывчатых веществ