Drilling and demolition of rocks by pulsed power

Lisitsyn, I.V.; Inoue, Hirotoshi; Katsuki, S.; Akiyama, H.; Nishizawa, Izumi

doi:10.1109/ppc.1999.825439

Cited by 34 publications

(21 citation statements)

References 2 publications

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“…1,2 The main advantage of the used pulsed power is that it is not only ecologically clean, 1,3 but also high efficient. 4,5 The destruction is realized under the following conditions: 6 Two electrodes are placed on the surface of a rock. The rock is immersed into a high permittivity liquid.…”

Section: Introductionmentioning

confidence: 99%

“…The fact that the dielectric strength of liquids is higher than that of solids at the times of voltage duration less than 1µs was founded at Tomsk Polytechnic University at end of fiftieth. 4 In early sixties, it was also found that for very short voltage pulses, the breakdown inside the solid dielectric occurs faster than the surface flashover between the electrodes. 8 It seems that discharge channels can penetrate in solids as long as the voltage duration is short and the voltage amplitude is high.…”

Section: Introductionmentioning

confidence: 99%

“…The solid destruction occurs when the introduced energy in the discharge channel is enough. 4,10 It was shown by calculation that the coefficient of the generator energy transformation into wave energy of mechanical stress is only 0.1∼0.2 because of the limitation of the effective ratio of specific adiabatic heats. 7,11 Thus, the pulse power is also required to be large enough to break down the solid.…”

Section: Introductionmentioning

confidence: 99%

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Discharge characteristics of high voltage pulses inside rocks with increasing their applied number

Zhang

Liu

et al. 2017

AIP Advances

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By conducting experiments for granite and sandstone samples under different conditions, such as voltage amplitude and electrodes gap, the discharge characteristics of high voltage pulses inside the rocks with increasing their applied number have been investigated. In each of the experiments, a certain value for voltage amplitude and electrodes gap is set separately and then, pulses are applied on same surface of the rocks continuously. The time dependent voltage between the electrodes, the current in plasma and the transient states around the electrode tips are measured and recorded separately when each of the pulses is applied. By means of the wave forms of the voltage and the current, variation laws of the discharging time and the energy release into the plasma with increasing applied pulses number have been obtained. The relation between the number of applied pulses and the critical condition of discharge inside of the rocks has been found. Further, the relation between the number of applied pulses required to discharge and the voltage amplitude has been also analyzed. The reasons of why increasing applied pulses number has such effects on discharge characteristics of them inside the granite and sandstone samples have been found and demonstrated.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Discharge characteristics of high voltage pulses inside rocks with increasing their applied number

Zhang

Liu

et al. 2017

AIP Advances

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“…without damaging them. There are no negative effects inherent to explosives as well [2][3][4]. In present paper the method of phased splitting off by electro-blast are presented, and experimental results are given and discussed.…”

Section: Introductionmentioning

confidence: 99%

A phased splitting off from the high-strength concrete by an electro-blasting method

Voitenko¹,

Yudin²

2016

AIP Conference Proceedings

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A phased splitting off from the monolith concrete block via electro-blasting method have been described. The results of experiments using the high-current pulse generator with operating voltage up to 15 kV and maximum stored energy of 126 kJ with initiation of the discharge in two boreholes were presented. The step by step electro-blast were produced simultaneous within boreholes drilled in the cast in the ground concrete monolith. Each subsequent electro-blast was performed in the boreholes pair situated farther from the free surface. Boreholes in each pair were drilled at a distance of 30-40 cm from each other, and of 25 cm apart from line of previous pair. It is shown that the electro-blasts leads to formation of main cracks at the predefined direction via boreholes line as well as main cracks lead to creation of a new free surfacethat help to form the desirable wave interference at the next step of the electro-blast

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“…This cannot be solely explained by the existing breakdown theory of either solid or liquid (Lisitsyn et al, 1999a). Comparative experimental results shown that while all dry granite or tuff samples were broken down by electrical disintegrator, there was no destruction events in water-saturated sample in which the air in the voids was replaced by water.…”

Section: Role Of Gas-filled Pores In the Electrical Disintegration Ofmentioning

confidence: 86%

A study of the applications and modelling of high voltage pulse comminution for mineral ores

Zuo¹

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The pre-treatment of ore particles by high voltage pulses (HVP) at low specific energy has a potential to reduce the energy consumption and operation costs. Nevertheless, the influencing factors and the behavior of HVP breakage of ore particles have not yet been fully understood. The overall objective of this thesis is to study the applications and modelling of HVP breakage by understanding the behaviour of ore particles subjected to pulse discharge. The three areas investigated are:1)The effects of mineral properties on HVP selective breakage and the application of this selective breakage in ore pre-concentration.2) The methods to evaluate and to characterize HVP breakage results. 3)Modelling ore particle behavior in HVP breakage.In this project, the selectivity of HVP breakage is studied using synthetic samples made of construction grout and pyrite grains. The result confirms that the breakage response of particles is dominated by the locality of electrical breakdown channel. The electrical breakdown channel locality is controlled by the grains of minerals with high conductivity/permittivity and their location in a particle. This understanding has led to the discovery of a novel technique for ore preconcentration using high voltage electrical pulses. The technique utilises metalliferous graininduced selective breakage, under a controlled pulse energy loading, and size-based screening to separate the feed ore into two products for splitting of ores by grade.To evaluate HVP breakage results, a t 10 -based model was developed to predict the degree of impact breakage, t 10 , of pulse-treated particles from that of untreated particles. This model incorporates only one parameter, C Ab , which is equivalent to percentage change of A×b values. The t 10 -based model can be used to assess energy reduction due to the pre-weakening effect in the downstream mechanical comminution process. A Wide-size JKRBT characterisation method was created, initially for quick determination of breakage characteristics of the HVP product; ultimately for use as an express ore breakage characterisation method. In this method, particles in wide size range are tested as one size class in the JKRBT by single-particle breakage mode, significantly simplifying the feed particles preparing and product sizing procedures. A conceptual design of an on-line ore ii competence measuring system based on this principle is proposed. Both the t10-based model and the Wide-size JKRBT method utilise a size-dependent breakage model previously developed by the JKMRC.Behaviour of ore particles in HVP breakage was investigated with a pilot scale and a laboratory scale HVP breakage devices. The effects of specific energy, pulse voltage, cumulative discharges, feed particle size and ore particle breakage pattern (body breakage or surface breakage) were investigated. Based on the data, a model structure for HVP breakage was developed, which incorporates four sub-models using the similar structure to predict four HVP breakage indices: body breakage probability...

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Drilling and demolition of rocks by pulsed power

Cited by 34 publications

References 2 publications

Discharge characteristics of high voltage pulses inside rocks with increasing their applied number

Discharge characteristics of high voltage pulses inside rocks with increasing their applied number

A phased splitting off from the high-strength concrete by an electro-blasting method

A study of the applications and modelling of high voltage pulse comminution for mineral ores

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