Analiza i porównanie metody ciągłego pomiaru prędkości detonacji z metodą znormalizowaną

Prędkość detonacji jest jednym z parametrów charakteryzujących materiały wybuchowe. Na jej wartość wpływa wiele czynników związanych z warunkami, w jakich są stosowane. Wartość prędkości detonacji zmierzonej w otworze strzałowym może różnić się od wartości zmierzonej metodami znormalizowanymi w warunkach laboratoryjnych. W związku z powyższym przeprowadzono badania porównawcze metod pomiaru prędkości detonacji, w tym metody odcinkowej (zgodnej z normą EN 13631-14:2003) oraz ciągłej (przy pomocy urządzenia MicroTrap VOD/Data Recorder). Przeprowadzono także analizę wpływu temperatury otoczenia na zmianę oporności sond pomiarowych w ciągłym systemie pomiaru prędkości detonacji. Na podstawie przeprowadzonych badań porównawczych dla 5 typów nabojowanych materiałów wybuchowych emulsyjnych stosowanych w górnictwie stwierdzono, że przyrząd MicroTrap pozwala na uzyskanie wyników komplementarnych z wynikami badań prowadzonymi metodą znormalizowaną

Tests of expansive material influence on the spontaneous combustion of coal and the environment of blastholes bored in the coal bed

Środek rozprężny jest niewybuchową substancją przeznaczoną do rozsadzania materiałów nieplastycznych. Efektem ubocznym reakcji chemicznej, zachodzącej w procesie hydratacji tego środka, jest duża ilość ciepła. Środek rozprężny jest od kilku lat kompleksowo badany pod kątem bezpiecznego używania w kopalniach wydobywających węgiel kamienny. Możliwość zastosowania tego typu środków na szerszą skalę w kopalniach wydobywających węgiel kamienny wymaga przeprowadzenia szeregu badań, które wykluczą możliwość zwiększenia istniejących zagrożeń w trakcie jego stosowania. Celem pracy było skonstruowanie dedykowanego stanowiska badawczego oraz przeprowadzenie badań mających na celu wykazanie bezpieczeństwa stosowania środka rozprężnego w pokładach węgla skłonnych do samozapalania oraz określenie jego skuteczności przy pomocy badań szczelinowatości bezpośrednio w pokładzie węglowym za pomocą metody introskopowej.An expansive material is a non-explosive substance intended for the breaking of inelastic material. A side effect of the chemical reaction occurring during the hydration process of this material is the great quantity of heat. Expansive materials have been undergoing complex testing for several years from the perspective of their safe application in hard coal mines. The possibility of using these materials on a broader scale in hard coal mines requires the conduction of a series of tests that may exclude the likelihood of increasing already present hazards as a result of their application. The goal of the work presented in this article was to construct a dedicated test stand and to conduct tests intended to demonstrate the safety of using expansive material in coal beds susceptible to spontaneous combustion, as well as to determine their efficiency by investigating the fracture porosity directly in the coal bed using endoscopy

Determination of the Detonation Velocity of Selected Ideal Explosives by the Use of Continuous and Start-stop Methods

W trakcie oznaczania prędkości detonacji górniczych materiałów wybuchowych przy użyciu urządzenia MicroTrap pojawiło się wiele wątpliwości dotyczących dokładności otrzymywanych wyników pomiarów ze względu na zastosowany materiał badawczy. W związku z powyższym przeprowadzono serię pomiarów prędkości detonacji idealnych materiałów wybuchowych (oktogen flegmatyzowany, heksogen flegmatyzowany, trotyl) przy użyciu Explometru Wielokanałowego oraz rejestratora MicroTrap. W trakcie badań, te same ładunki materiału wybuchowego i w tych samych warunkach zostały uzbrojone sondami do obu systemów pomiarowych. W ramach artykułu przedstawiono wyniki pomiarów prędkości detonacji idealnych materiałów wybuchowych przeprowadzonych metodą ciągłą i odcinkową (zwarciową).During the measurements of the detonation velocity of mining explosives using the MicroTrap VOD/Data Recorder, many doubts arose regarding the accuracy of the results obtained. Consequently, a series of detonation velocity tests of ideal explosives (phlegmatized HMX, phlegmatized RDX, TNT) by the use of multi-channel Explomet and MicroTrap recorder were carried out. The same explosives under the same conditions were fitted with continuous and start-stop probes during the tests. The article presents the results of detonation velocity measurements of ideal explosives carried out by the use of continuous and start-stop methods (short-circuit)

Wpływ dodatku aluminium na wybrane parametry detonacyjne materiału wybuchowego emulsyjnego luzem

W artykule dokonano oceny wpływu zawartości dodatku pyłu aluminiowego na wybrane parametry detonacyjne materiału wybuchowego emulsyjnego luzem uczulanego chemicznie. Analiza zawierała oznaczenie zdolności do wykonania pracy na wahadle balistycznym i w blokach ołowianych, pomiar ciśnienia fali podmuchu oraz pomiar prędkości detonacji. Do badań zastosowano pięć typów materiału wybuchowego emulsyjnego różniących się procentową zawartością aluminium, tj. 0, 1, 3, 5 i 7%

Study of rock fracture under blast loading

A study of dolomite rock material failure using a simple small-scale blast setup is presented. Laboratory tests were conducted using disc specimens drilled with a borehole in the center. A detonation cord and a blasting cap were fitted inside the borehole to induce cracking and fracturing of the specimens. The specimens were inserted between two steel plates, which were compressed against the specimen using bolt screws. Prior to testing, the most suitable screw torque for constraining the vertical displacement of the specimen surfaces without compressing the specimen was selected based on numerical simulations. Then, the experimental tests with the blasting cap were simulated using the Johnson–Holmquist II (JH-2) material model, and the properties of the blasting cap were determined and verified in two special tests with a lead specimen. Possessing the validated model, the influence of specimen thickness on the cracking patterns was finally analyzed. This paper presents a relatively easy method for studying rock material behavior under blast loading and for validating the numerical and constitutive models used for rock simulations

Thermodynamic Assessment of the Impact of Selected Plastics on the Energy Parameters of Explosives

Global economic development and the associated increase in consumption increase the demand for plastics. The result of these changes is the increase in the share of this group of used plastics in the structure of household waste. An innovative way of managing plastic waste is to use it as a component of a high-energy material. According to the conceptual assumptions, some plastics introduced into the structure of an explosive (Ex) in appropriate amounts can improve the energy parameters of a high-energy material. Modification of the composition of the explosive causes a change in its explosive and operational parameters. It also becomes necessary to develop a method of introducing an additional component. Computer programs for thermodynamic calculations are a tool for modeling the predicted energy parameters of an explosive. The performed simulations and modeling allow for the selection of appropriate compositions for laboratory and “in situ” tests. This reduces the number of field tests performed. This enables the more effective design of new explosive compositions. The use of waste plastics as a corrector of explosive properties may also be pro-environmental in nature through the use of a detonation method of their disposal and will reduce the cost of manufacturing the product. The conducted analyses showed that for three ANFO-type explosives containing 2% polyethylene—PE 2.0, 1% polypropylene—PP 1.0 and 1% polyurethane—PU 1.0, obtained energy parameters similar to ANFO and qualitatively and quantitatively similar structure of post-detonation gases

Thermodynamic Assessment of the Impact of Selected Plastics on the Energy Parameters of Explosives

Global economic development and the associated increase in consumption increase the demand for plastics. The result of these changes is the increase in the share of this group of used plastics in the structure of household waste. An innovative way of managing plastic waste is to use it as a component of a high-energy material. According to the conceptual assumptions, some plastics introduced into the structure of an explosive (Ex) in appropriate amounts can improve the energy parameters of a high-energy material. Modification of the composition of the explosive causes a change in its explosive and operational parameters. It also becomes necessary to develop a method of introducing an additional component. Computer programs for thermodynamic calculations are a tool for modeling the predicted energy parameters of an explosive. The performed simulations and modeling allow for the selection of appropriate compositions for laboratory and “in situ” tests. This reduces the number of field tests performed. This enables the more effective design of new explosive compositions. The use of waste plastics as a corrector of explosive properties may also be pro-environmental in nature through the use of a detonation method of their disposal and will reduce the cost of manufacturing the product. The conducted analyses showed that for three ANFO-type explosives containing 2% polyethylene—PE 2.0, 1% polypropylene—PP 1.0 and 1% polyurethane—PU 1.0, obtained energy parameters similar to ANFO and qualitatively and quantitatively similar structure of post-detonation gases

The Influence of Time on the Density and Detonation Velocity of Bulk Emulsion Explosives – a Case Study from Polish Copper Mines

The basic method for emulsion matrix sensitisation is chemical reduction of the density by producing in situ gas bubbles. The mixing of the components takes place directly inside the loading hose, which is equipped with a mixing device. Due to the multi-component nature of the mixture, the precise dosing of individual components has a key influence on the detonation behaviour of the final product. Unfortunately, keeping the mixing and charging of UG mobile units in good working condition in underground mines is a considerable challenge. As a result, completely different detonation parameters may be observed when charging the same explosive into blast holes using two different units. The aim of the present study was to determine the behaviour of the mechanically loaded emulsion explosives used in Polish underground copper mines by tracking the changes in the density and detonation velocity over time. Samples of the explosives were collected from selected mobile units. In addition, the influence of the quantity of the sensitising agent on the changes in the emulsion density and VOD was studied

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

Application of Silicon Dioxide as the Inert Component or Oxide Component Enhancer in ANFO

Non-ideal explosives with differing contents of silicon dioxide (silica or dioxosilane) added in the form of powder and gel were tested. Measurements of structure, crystallinity and morphology were performed by means of infrared spectroscopy (IR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). IR and XRD analysis revealed a lack of SiO2 influence on the non-ideal explosive structure. SEM analysis indicated that all the surface deformations of ammonium nitrate(V) prill were filled by a thin fuel film layer on which SiO2 was present. The additional calculations of selected theoretical properties of non-ideal compositions were made using ZMWCyw software. Based on this, it was established that the optimum semimetal content was 1.0 wt.%. Blasting tests confirmed that the addition of 1.0 wt.% SiO2 to the Ammonium Nitrate Fuel Oil (ANFO) resulted in the lowest volume of post-blast fumes. Moreover, it was established that finer SiO2 powder cannot be used as the oxide component enhancer due to the inhibition of detonation reaction. SiO2 should be used only as an inert component