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T N Singh - One of the best experts on this subject based on the ideXlab platform.
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Explosive Energy Utilization Enhancement with Air-Decking and Stemming Plug, ‘SPARSH’ ☆
Procedia Engineering, 2017Co-Authors: M. R. Saharan, M. Sazid, T N SinghAbstract:Engineering blasting is considered the most economical means of rock fragmentation. The Explosive Energy utilization is limited to 7% to 22% for fracturing and fragmentation though. The rest of Energy components manifests itself into deleterious effects of engineering blasting, namely – noise, air overpressure, ground vibrations, etc. It has been established that proper application of air-decking and stemming plugs may enhance Explosive Energy utilization to a good extent. This paper substantiates this fact wherein distinct Explosive Energy utilization enhancement has been achieved with the combination of air-decking and stemming plug. The stemming plug used has acronym as, SPARSH (Stemming Plug Augmenting Resistance to Stemming in Holes) and it is perhaps the only available device which can effectively be used with air-decking. Further, SPARSH doesn’t restrict the type of stemming material and stemming length. This is a significant advancement in the engineering blasting.
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numerical assessment of spacing burden ratio to effective utilization of Explosive Energy
International journal of mining science and technology, 2015Co-Authors: Mohd Sazid, T N SinghAbstract:Abstract The spacing–burden (S/B) ratio plays significant role on rock fragmentation and proper utilization of Explosive Energy to minimize the undesirable damage. Low S/B ratio generates fine fragments due to pressure rings coalescence of two blast holes, whereas boulder generations were observed above optimum S/B ratio. Both conditions are not acceptable because of wastage of Explosive Energy. Therefore, to resolve this issue, a numerical model study was conducted to optimize the S/B ratio and to envisage its effect on rock fragmentation based on utilization of Explosive Energy. Finite element simulation tool was used to see the extent of two blast hole influence area variation with varying S/B ratio. The better results were obtained at S/B ratio of 1:2 with optimum utilization of peak Explosive Energy. The performance was observed based on peak kinetic Energy, peak pressure, radial and hoop stresses on centre of the two blast holes, where pressure rings coalescence.
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an intelligent approach to prediction and control ground vibration in mines
Geotechnical and Geological Engineering, 2005Co-Authors: T N Singh, V K SinghAbstract:Drilling and Blasting are still considered to be the most economical method for rock excavation either on surface or underground. The Explosive Energy, which breaks the rockmass, is not fully utilized for this purpose. Only 20–30% of Explosive Energy is utilized for fragmenting the rockmass and the rest wasted away in the form of ground vibration, air blast, noise, fly rock, back breaks, etc. Among them, ground vibration is considered to have the most damaging effect. A number of predictor equations have been proposed by various researchers to predict ground vibration prior to blasting. Still, it is difficult to recommend any one predictor for a particular ground condition because ground vibration is influenced by a number of parameters. These parameters are either controllable or non-controllable like blast geometry, Explosive types, rock strength properties, joints patterns, etc. In the present paper, an attempt has been made to predict the ground vibration using an Artificial Neural Network incorporating large number of parameters, which affect the ground vibration. Results are also compared with the values obtained from regression analysis and observed field data sets. Finally, it is found that the neural network approach is more accurate and able to predict the value of blast vibration without increasing error with increasing number of inputs and non-linearity among these.
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An intelligent approach to prediction and control ground vibration in mines
Geotechnical & Geological Engineering, 2005Co-Authors: T N Singh, Virendra SinghAbstract:Drilling and Blasting are still considered to be the most economical method for rock excavation either on surface or underground. The Explosive Energy, which breaks the rockmass, is not fully utilized for this purpose. Only 20–30% of Explosive Energy is utilized for fragmenting the rockmass and the rest wasted away in the form of ground vibration, air blast, noise, fly rock, back breaks, etc. Among them, ground vibration is considered to have the most damaging effect. A number of predictor equations have been proposed by various researchers to predict ground vibration prior to blasting. Still, it is difficult to recommend any one predictor for a particular ground condition because ground vibration is influenced by a number of parameters. These parameters are either controllable or non-controllable like blast geometry, Explosive types, rock strength properties, joints patterns, etc. In the present paper, an attempt has been made to predict the ground vibration using an Artificial Neural Network incorporating large number of parameters, which affect the ground vibration. Results are also compared with the values obtained from regression analysis and observed field data sets. Finally, it is found that the neural network approach is more accurate and able to predict the value of blast vibration without increasing error with increasing number of inputs and non-linearity among these.
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prediction of blast induced air overpressure in opencast mine
Noise & Vibration Worldwide, 2005Co-Authors: Manoj Khandelwal, T N SinghAbstract:Blasting is still considered to be the most economical technique for rock excavation and displacement either on the surface or underground. The Explosive Energy, which fractures the rockmass is not...
C. Forsyth - One of the best experts on this subject based on the ideXlab platform.
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A diagnosis of the plasma waves responsible for the Explosive Energy release of substorm onset
Nature Communications, 2018Co-Authors: N. M. E. Kalmoni, I. J. Rae, C. E. J. Watt, K. R. Murphy, M. Samara, R. G. Michell, G. Grubbs, C. ForsythAbstract:During geomagnetic substorms, stored magnetic and plasma thermal energies are Explosively converted into plasma kinetic Energy. This rapid reconfiguration of Earth’s nightside magnetosphere is manifest in the ionosphere as an auroral display that fills the sky. Progress in understanding of how substorms are initiated is hindered by a lack of quantitative analysis of the single consistent feature of onset; the rapid brightening and structuring of the most equatorward arc in the ionosphere. Here, we exploit state-of-the-art auroral measurements to construct an observational dispersion relation of waves during substorm onset. Further, we use kinetic theory of high-beta plasma to demonstrate that the shear Alfven wave dispersion relation bears remarkable similarity to the auroral dispersion relation. In contrast to prevailing theories of substorm initiation, we demonstrate that auroral beads seen during the majority of substorm onsets are likely the signature of kinetic Alfven waves driven unstable in the high-beta magnetotail. The origin of geomagnetic substorms is still uncertain due to lack of comprehensive quantitative analyses. Here, the authors construct an observational dispersion relation of auroral forms that correspond to the Explosive Energy release from substorm onset.
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A diagnosis of the plasma waves responsible for the Explosive Energy release of substorm onset.
Nature communications, 2018Co-Authors: N. M. E. Kalmoni, I. J. Rae, C. E. J. Watt, K. R. Murphy, M. Samara, R. G. Michell, G. A. Grubbs, C. ForsythAbstract:During geomagnetic substorms, stored magnetic and plasma thermal energies are Explosively converted into plasma kinetic Energy. This rapid reconfiguration of Earth’s nightside magnetosphere is manifest in the ionosphere as an auroral display that fills the sky. Progress in understanding of how substorms are initiated is hindered by a lack of quantitative analysis of the single consistent feature of onset; the rapid brightening and structuring of the most equatorward arc in the ionosphere. Here, we exploit state-of-the-art auroral measurements to construct an observational dispersion relation of waves during substorm onset. Further, we use kinetic theory of high-beta plasma to demonstrate that the shear Alfven wave dispersion relation bears remarkable similarity to the auroral dispersion relation. In contrast to prevailing theories of substorm initiation, we demonstrate that auroral beads seen during the majority of substorm onsets are likely the signature of kinetic Alfven waves driven unstable in the high-beta magnetotail.
Donald B. Dingwell - One of the best experts on this subject based on the ideXlab platform.
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Experimental investigations on the explosivity of steam-driven eruptions: a case study of Solfatara volcano (Campi Flegrei)
Journal of geophysical research. Solid earth, 2016Co-Authors: Cristian Montanaro, Bettina Scheu, Klaus F. X. Mayer, Giovanni Orsi, Roberto Moretti, Roberto Isaia, Donald B. DingwellAbstract:Steam-driven eruptions, both phreatic and hydrothermal, expel exclusively fragments of non-juvenile rocks disintegrated by the expansion of water as liquid or gas phase. As their violence is related to the magnitude of the decompression work that can be performed by fluid expansion, these eruptions may occur with variable degrees of explosivity. In this study we investigate the influence of liquid fraction and rock petrophysical properties on the steam-driven Explosive Energy. A series of fine-grained heterogeneous tuffs from the Campi Flegrei caldera were investigated for their petrophysical properties. The rapid depressurization of various amounts of liquid water within the rock pore space can yield highly variable fragmentation and ejection behaviors for the investigated tuffs. Our results suggest that the pore liquid fraction controls the stored Explosive Energy with an increasing liquid fraction within the pore space increasing the Explosive Energy. Overall, the Energy released by steam flashing can be estimated to be 1 order of magnitude higher than for simple (Argon) gas expansion and may produce a higher amount of fine material even under partially saturated conditions. The Energy surplus in the presence of steam flashing leads to a faster fragmentation with respect to gas expansion and to higher ejection velocities imparted to the fragmented particles. Moreover, weak and low permeability rocks yield a maximum fine fraction. Using experiments to unravel the energetics of steam-driven eruptions has yielded estimates for several parameters controlling their explosivity. These findings should be considered for both modeling and evaluation of the hazards associated with steam-driven eruptions.
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“Explosive Energy” during volcanic eruptions from fractal analysis of pyroclasts
Earth and Planetary Science Letters, 2006Co-Authors: Ulrich Kueppers, Diego Perugini, Donald B. DingwellAbstract:Despite recent advances by means of experiments and high-resolution surveys and the growing understanding of the physical processes before and during volcanic eruptions, duration and type of eruptive activity still remain highly unpredictable. This uncertainty hinders appropriate hazard and associated risk assessment tremendously. In an effort to counter this problem, experimentally generated pyroclasts have been studied by fractal statistics with the aim of evaluating possible relationships between eruption Energy and fragmentation efficiency. Rapid decompression experiments have been performed on three differently porous sample sets of the 1990–1995 eruption of Unzen volcano (Japan) at 850 °C and at initial pressure values above the respective fragmentation threshold [U. Kueppers, B. Scheu, O. Spieler, D. B. Dingwell, Fragmentation efficiency of Explosive volcanic eruptions: a study of experimentally generated pyroclasts. J. Volcanol. Geotherm. Res. 153 (2006) 125–135.,O. Spieler, B. Kennedy, U. Kueppers, D.B. Dingwell, B. Scheu, J. Taddeucci, The fragmentation threshold of pyroclastic rocks. EPSL 226 (2004) 139–148.]. The size distribution of generated pyroclasts has been studied by fractal fragmentation theory and the fractal dimension of fragmentation (Df), a value quantifying the intensity of fragmentation, has been measured for each sample. Results showthat size distribution of pyroclastic fragments follows a fractal law(i.e. power-law) in the investigated range of fragment sizes, indicating that fragmentation of experimental samples reflects a scale-invariant mechanism. In addition, Df is correlated positively with the potential Energy for fragmentation (PEF) while showing a strong influence of the open porosity of the samples. Results obtained in this work indicate that fractal fragmentation theory may allow for quantifying fragmentation processes during Explosive volcanic eruptions by calculating the fractal dimension of the size distribution of pyroclasts. It emerges fromthis study that fractal dimension may be utilised as a proxy for estimating the explosivity of volcanic eruptions by analysing their natural pyroclastic deposits.Published800-807ope
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“Explosive Energy” during volcanic eruptions from fractal analysis of pyroclasts
Earth and Planetary Science Letters, 2006Co-Authors: Ulrich Kueppers, Diego Perugini, Donald B. DingwellAbstract:Abstract Despite recent advances by means of experiments and high-resolution surveys and the growing understanding of the physical processes before and during volcanic eruptions, duration and type of eruptive activity still remain highly unpredictable. This uncertainty hinders appropriate hazard and associated risk assessment tremendously. In an effort to counter this problem, experimentally generated pyroclasts have been studied by fractal statistics with the aim of evaluating possible relationships between eruption Energy and fragmentation efficiency. Rapid decompression experiments have been performed on three differently porous sample sets of the 1990–1995 eruption of Unzen volcano (Japan) at 850 °C and at initial pressure values above the respective fragmentation threshold [U. Kueppers, B. Scheu, O. Spieler, D.B. Dingwell, Fragmentation efficiency of Explosive volcanic eruptions: a study of experimentally generated pyroclasts. J. Volcanol. Geotherm. Res. 153 (2006) 125–135.,O. Spieler, B. Kennedy, U. Kueppers, D.B. Dingwell, B. Scheu, J. Taddeucci, The fragmentation threshold of pyroclastic rocks. EPSL 226 (2004) 139–148.]. The size distribution of generated pyroclasts has been studied by fractal fragmentation theory and the fractal dimension of fragmentation (Df), a value quantifying the intensity of fragmentation, has been measured for each sample. Results show that size distribution of pyroclastic fragments follows a fractal law (i.e. power-law) in the investigated range of fragment sizes, indicating that fragmentation of experimental samples reflects a scale-invariant mechanism. In addition, Df is correlated positively with the potential Energy for fragmentation (PEF) while showing a strong influence of the open porosity of the samples. Results obtained in this work indicate that fractal fragmentation theory may allow for quantifying fragmentation processes during Explosive volcanic eruptions by calculating the fractal dimension of the size distribution of pyroclasts. It emerges from this study that fractal dimension may be utilised as a proxy for estimating the explosivity of volcanic eruptions by analysing their natural pyroclastic deposits.
Mohd Sazid - One of the best experts on this subject based on the ideXlab platform.
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numerical assessment of spacing burden ratio to effective utilization of Explosive Energy
International journal of mining science and technology, 2015Co-Authors: Mohd Sazid, T N SinghAbstract:Abstract The spacing–burden (S/B) ratio plays significant role on rock fragmentation and proper utilization of Explosive Energy to minimize the undesirable damage. Low S/B ratio generates fine fragments due to pressure rings coalescence of two blast holes, whereas boulder generations were observed above optimum S/B ratio. Both conditions are not acceptable because of wastage of Explosive Energy. Therefore, to resolve this issue, a numerical model study was conducted to optimize the S/B ratio and to envisage its effect on rock fragmentation based on utilization of Explosive Energy. Finite element simulation tool was used to see the extent of two blast hole influence area variation with varying S/B ratio. The better results were obtained at S/B ratio of 1:2 with optimum utilization of peak Explosive Energy. The performance was observed based on peak kinetic Energy, peak pressure, radial and hoop stresses on centre of the two blast holes, where pressure rings coalescence.
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Numerical assessment of spacing–burden ratio to effective utilization of Explosive Energy
International Journal of Mining Science and Technology, 2015Co-Authors: Mohd Sazid, Trilok SinghAbstract:Abstract The spacing–burden (S/B) ratio plays significant role on rock fragmentation and proper utilization of Explosive Energy to minimize the undesirable damage. Low S/B ratio generates fine fragments due to pressure rings coalescence of two blast holes, whereas boulder generations were observed above optimum S/B ratio. Both conditions are not acceptable because of wastage of Explosive Energy. Therefore, to resolve this issue, a numerical model study was conducted to optimize the S/B ratio and to envisage its effect on rock fragmentation based on utilization of Explosive Energy. Finite element simulation tool was used to see the extent of two blast hole influence area variation with varying S/B ratio. The better results were obtained at S/B ratio of 1:2 with optimum utilization of peak Explosive Energy. The performance was observed based on peak kinetic Energy, peak pressure, radial and hoop stresses on centre of the two blast holes, where pressure rings coalescence.
N. M. E. Kalmoni - One of the best experts on this subject based on the ideXlab platform.
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A diagnosis of the plasma waves responsible for the Explosive Energy release of substorm onset
Nature Communications, 2018Co-Authors: N. M. E. Kalmoni, I. J. Rae, C. E. J. Watt, K. R. Murphy, M. Samara, R. G. Michell, G. Grubbs, C. ForsythAbstract:During geomagnetic substorms, stored magnetic and plasma thermal energies are Explosively converted into plasma kinetic Energy. This rapid reconfiguration of Earth’s nightside magnetosphere is manifest in the ionosphere as an auroral display that fills the sky. Progress in understanding of how substorms are initiated is hindered by a lack of quantitative analysis of the single consistent feature of onset; the rapid brightening and structuring of the most equatorward arc in the ionosphere. Here, we exploit state-of-the-art auroral measurements to construct an observational dispersion relation of waves during substorm onset. Further, we use kinetic theory of high-beta plasma to demonstrate that the shear Alfven wave dispersion relation bears remarkable similarity to the auroral dispersion relation. In contrast to prevailing theories of substorm initiation, we demonstrate that auroral beads seen during the majority of substorm onsets are likely the signature of kinetic Alfven waves driven unstable in the high-beta magnetotail. The origin of geomagnetic substorms is still uncertain due to lack of comprehensive quantitative analyses. Here, the authors construct an observational dispersion relation of auroral forms that correspond to the Explosive Energy release from substorm onset.
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A diagnosis of the plasma waves responsible for the Explosive Energy release of substorm onset.
Nature communications, 2018Co-Authors: N. M. E. Kalmoni, I. J. Rae, C. E. J. Watt, K. R. Murphy, M. Samara, R. G. Michell, G. A. Grubbs, C. ForsythAbstract:During geomagnetic substorms, stored magnetic and plasma thermal energies are Explosively converted into plasma kinetic Energy. This rapid reconfiguration of Earth’s nightside magnetosphere is manifest in the ionosphere as an auroral display that fills the sky. Progress in understanding of how substorms are initiated is hindered by a lack of quantitative analysis of the single consistent feature of onset; the rapid brightening and structuring of the most equatorward arc in the ionosphere. Here, we exploit state-of-the-art auroral measurements to construct an observational dispersion relation of waves during substorm onset. Further, we use kinetic theory of high-beta plasma to demonstrate that the shear Alfven wave dispersion relation bears remarkable similarity to the auroral dispersion relation. In contrast to prevailing theories of substorm initiation, we demonstrate that auroral beads seen during the majority of substorm onsets are likely the signature of kinetic Alfven waves driven unstable in the high-beta magnetotail.
