Wyniki wyszukiwania - BazTech

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The effect of blasting using low-density emulsion explosives

Skrlec Vinko, Dobrilovic Mario, Tumara Barbara S., Bohanek Vjecislav

Journal of Sustainable Mining

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2024

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Vol. 23, iss. 1

10--19

EN

Low-density emulsion explosives are essentially blends of an emulsion matrix and a certain amount of gaseous phase inclusions acting as hot spots. With the addition of expanded polystyrene for gaseous sensibilization, the resulting explosive blend was developed to reduce peak values and pressure impulse of gaseous detonation products on surrounding rock. This resulted in a decrease in rock stress and a decrease in cracking zone width outside of the minefield boundary. The use of low-density emulsion explosives correlates with the decrease in the seismic effect of blasting, more precisely, the decrease of induced rock oscillation velocities. The low-density emulsion explosive used in this work was validated based on laboratory and field experiments. The laboratory experiments measured dominantly detonation and safety characteristics, while field experiments characterized working capacity, i.e. single-shot blasting effect in an igneous diabase. The obtained measurements were compared against reference explosives (pentrite, emulsion explosive sensitized with glass microspheres, and ANFO explosive). Measured parameters were detonation velocity and oscillation velocity used to determine the seismic effect of blasting in the immediate borehole vicinity.

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Estimation of active rockburst prevention effectiveness during longwall mining under disadvantageous geological and mining conditions

Wojtecki Ł., Konicek P.

Journal of Sustainable Mining

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2016

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Vol. 15, iss. 1

1--7

EN

Underground longwall mining of coal seams in the Upper Silesian Coal Basin is currently being carried out under increasingly difficult geological and mining conditions. Mining depth, dislocations and mining remnants are the main factors responsible for the most significant rockburst hazard, which can be minimized via the use of active and passive rockburst prevention. Active rockburst prevention in longwalls is usually based on blasting, in order to either destress local stress concentrations in the rock mass or to fracture the thick layers of strong roof rocks to prevent or minimize the impact of high energy tremors on excavations. The accurate estimation of active rockburst prevention effectiveness is particularly important when mining under disadvantageous geological and mining conditions, which are associated with high levels of this hazard. The efficiency of blasting applied for this purpose is typically evaluated from the seismic effect, which is calculated based on seismic monitoring data and the weight of the charged explosive. This method, as used previously in the Czech Republic, was adopted in the present study to analyze conditions occurring in a Polish hard coal mine in the Upper Silesian Coal Basin. Parameters of long hole destress blastings in roof rocks (torpedo blastings) from the face of the assigned longwall in coal seam no. 507 were correct a success according to the seismic effect method and corresponded to observations made in situ. The analytical method presented enables the rapid estimation of destress blasting effectiveness and could also be useful when determining appropriate active rockburst prevention.

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Research on the milisecond delay blasting impact in order to minimize seismic effects in Kučín quarry surrounding

Baulovič J., Pandula B., Kondela J.

Materiały Wysokoenergetyczne

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2015

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T. 7

5--13

EN

The intensity of seismic waves’ vibrations is proportional to the weight of the applied explosive. If the vibrations are sufficientin energy, surrounding buildings can be damaged or destroyed. Evaluating the negative effects of the blasting operations and quantification of the seismic safety is nowadays very actual and a challenging problem. The article presents the results of the analysis as well as an evaluation on seismic safety of the objects during blasting in the quarry Kučín. The results the evaluation seismic effects blasting verified in a Kučín quarry are the methodological base for evaluating the seismic effects of blasting in all quarries in Slovakia.