A pulsed power drilling system and method for measuring properties of a mineral substrate

Abstract

The technology disclosed relates to a pulsed power drilling system and methods for measuring properties of a mineral substrate by using at least one of the electrodes of the drill head of the pulsed power drilling system for measurement purposes. In particular, at least one of the electrodes of the drill head that is configured to be connected to a first electrical circuit for generating high voltage current pulses is also configured to be connected to a second circuit used for the purpose of measuring properties of the mineral substrate. At least one of the plurality of electrodes of the drill head that is configured to be used for passing a high voltage current pulse between two electrodes of the drill head via the mineral substrate for the purpose of breaking the mineral substrate may thereby also configured to function as a measurement electrode. The disclosed pulsed power drilling system and method may for example be applied in rock drilling, concrete processing, mineral processing, and continuous mining. The present disclosure further relates to a drill rig comprising a pulsed power drilling system and the use of a pulsed power drilling system.

Description

[0001] TITLE

[0002] A pulsed power drilling system and method for measuring properties of a mineral substrate

[0003] TECHNICAL FIELD

[0004] The present disclosure relates to a pulsed power drilling system, a drill rig comprising the pulsed power drilling system and methods for measuring properties of a mineral substrate by using at least one of the electrodes of the drill head of the pulsed power drilling system for measurement purposes. In particular, at least one of the electrodes of the drill head that is configured to be connected to a first electrical circuit for generating high voltage current pulses is also configured to be connected to a second circuit used for the purpose of measuring properties of the mineral substrate. The disclosed pulsed power drilling system and methods may for example be applied in rock drilling, concrete processing, mineral processing, and continuous mining. The present disclosure further relates to a drill rig comprising a pulsed power drilling system and the use of a pulsed power drilling system.

[0005] BACKGROUND

[0006] In the field of rock drilling, a new technology has emerged during the recent years, referred to as electro pulse boring (EPB), plasma channel drilling, pulsed plasma drilling, etc. The technology relies on mechanical electrodes creating contact with a rock material, and the application of a high voltage between the electrodes.

[0007] The discharge occurring, if successful, penetrates the rock material and breaks loose small pieces. In some applications, an insulating fluid is proposed to prevent direct discharge between the electrodes. For most applications however, water has to be used for practical reasons, and in some cases even saline water. This makes it crucial to achieve a good contact between the electrodes and the rock material, since the discharge path through the water will otherwise become more attractive than the desired discharge path via the rock material.

[0008] Various methods exist for characterizing rock materials. The most known is probably spectroscopy, where a high energy pulse or heat is applied to a material, and its emission spectrum is measured. Given the sensitive nature of such instruments, the analysis is typically done downstream from a drilling process, where the material has become an average of the drilled hole.

[0009] Core drilling is the go-to method for characterizing ore bodies that cannot (yet) be reached.

[0010] The current drilling process is typically “blind”. Best case, one has a broad overview of the rock mass from previous long-distance investigations such as core drilling. Such methods are expensive, and only cover small sections of the ore body. Once the mine is developed, core drilling can be performed with higher resolution, but is typically reserved for the “broad overview” rather than detailed mapping. Any analysis of material from the drilling process is reactional, many times as late as when the material reaches the processing plant.

[0011] Use of radar and impedance tomography would today need to be done with specialized equipment between drilling cycles, limiting their usability.

[0012] SUMMARY

[0013] In light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks associated with conventional pulsed power drilling tools.

[0014] A primary object of the present disclosure is to achieve an in at least some aspects improved pulsed power drilling system adapted for high resolution drilling and methods for achieving high resolution drilling without any need for expensive and / or separate specialized equipment.

[0015] The primary object is at least partly achieved by introducing a pulsed power drilling system that is adapted for high resolution drilling in that the pulsed power drilling system is also configured to perform accurate and precise measurements of properties of the mineral substrate to be drilled, without any need for expensive and separate specialized measurement equipment.

[0016] The primary object is at least partly achieved by introducing a pulsed power drilling system that is adapted for high resolution drilling in that the pulsed power drilling system is also configured to perform reliable and precise measurements of properties of the mineral substrate to be drilled by temporarily using at least one of the electrodes, typically at least two of the electrodes, of the drill head for measuring properties of the mineral substrate, or rock mass, without any need for expensive and separate specialized measurement equipment.

[0017] The primary object is at least partly achieved by configuring the pulsed power drilling system so that properties of the mineral substrate are measured by the pulsed power drilling system prior to the system is generating a high voltage current pulse that is allowed to pass between two electrodes of the drill head via the mineral substrate to break the mineral substrate.

[0018] The primary object is at least partly achieved by configuring the pulsed power drilling system so that at least one of the electrodes, and typically at least two of the electrodes, of the drill head configured to be temporarily connected to a first circuit of the pulsed power generator and carry a discharge generated by the pulsed power generator is / are also configured to be temporarily connected to a second circuit of a measurement unit and temporarily function as a measurement electrode used for accurately and reliably measuring properties of the mineral substrate to be drilled.

[0019] Other advantages of the pulsed power drilling system and methods according to the technology disclosed include the provision of accurate and rapid measurements and repetitious look-ahead, right before drilling, so that proactive adjustments of the system may be performed prior to generating a high voltage current pulse to thereby achieve high resolution drilling.

[0020] Further benefits of the technology disclosed include dual use of electrodes since at least one of the electrodes is configured to temporarily function as a measurement electrode and, typically, no additional specialized measurement equipment or separate antennas is required for measuring properties of the mineral substrate, or rock mass.

[0021] Yet another object of the present disclosure is the use of an improved pulsed power drilling system according to any of the embodiments disclosed and achieving an in at least some aspects improved drill rig comprising the improved pulsed power drilling system according to any of the embodiments disclosed.

[0022] According to the technology disclosed, at least one of the plurality of electrodes of the drill head that is configured to be used for passing a high voltage current pulse between two electrodes of the drill head via the mineral substrate for the purpose of breaking the mineral substrate is also configured to be used for measuring properties of the mineral substrate, for example by temporarily functioning as a measurement electrode. The disclosed pulsed power drilling system and methods may for example be applied in rock drilling, concrete processing, mineral processing, and continuous mining. The present disclosure further relates to a drill rig comprising a pulsed power drilling system and the use of a pulsed power drilling system.

[0023] According to certain aspects, the present disclosure relates to a pulsed power drilling system configured for passing a pulsed electrical current through a mineral substrate to break the mineral substrate, where the pulsed power drilling system comprises:

[0024] - a pulsed power generator comprising a first electrical circuit for generating high voltage current pulses,

[0025] - a drill head comprising a plurality of electrodes comprising a solid electrode portion configured to be connected to the pulsed power generator, and

[0026] - an arrangement for measuring properties of the mineral substrate comprising a second electrical circuit adapted to be used for measuring properties of the mineral substrate and configured to be temporarily connected to at least one of the electrodes of the drill head.

[0027] According to aspects of the disclosure, at least the primary object is achieved by a pulsed power drilling system configured for passing a pulsed electrical current through a mineral substrate to break the mineral substrate, and comprises:

[0028] - a pulsed power generator comprising a first electrical circuit for generating high voltage current pulses,

[0029] - a drill head comprising a plurality of electrodes comprising a solid electrode portion configured to be connected to the pulsed power generator, and

[0030] - an arrangement for measuring properties of the mineral substrate comprising a second electrical circuit adapted to be used for measuring properties of the mineral substrate and configured to be concurrently connected to at least two of the electrodes of the drill head. The technology disclosed relates to a pulsed power drilling system configured for passing a pulsed electrical current through a mineral substrate to break the mineral substrate, the pulsed power drilling system comprising:

[0031] - a pulsed power generator comprising a first circuit for generating high voltage current pulses,

[0032] - a drill head comprising a plurality of electrodes each comprising a solid electrode portion configured to be connected to the pulsed power generator and to carry a discharge generated by the pulsed power generator so as to allow for a high voltage current pulse generated by the pulsed power generator to pass between the respective electrode portion of two electrodes among the plurality of electrodes of the drill head via the mineral substrate, and

[0033] - an arrangement for measuring properties of the mineral substrate, wherein the arrangement for measuring is arranged and configured to include at least one of the solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator, and wherein the arrangement for measuring properties of the mineral substrate further comprises at least one second circuit different from the first circuit.

[0034] In embodiments, the at least one solid electrode portion is configured to be included in the arrangement for measuring properties of the mineral substrate is configured to be connected to the at least one second circuit when used for measuring properties of the mineral substrate and is further configured to be connected to the first circuit generating high voltage current pulses when carrying a discharge generated by the pulsed power generator.

[0035] In embodiments, at least one second circuit different from the first circuit is configured to supply a frequency-swept voltage signal that is applied between two of the electrodes. The resulting current is then measured by the measurement arrangement to determine the complex impedance and properties of the mineral substrate. The pulsed power drilling system may then comprise a control system for controlling the opening and closing of at least one switch of a switching arrangement so that the frequency-swept voltage signal is applied between the two electrodes of the drill head. In embodiments, at least one second circuit different from the first circuit is configured to supply a radar signal that is applied to and transmitted from at least one of the electrodes. The reflected radar signal is then detected by the measurement arrangement to determine properties of the mineral substrate. The pulsed power drilling system may then comprise a control system for controlling the opening and closing of at least one switch of a switching arrangement so that the radar signal is transmitted from at least one of the electrodes of the drill head and into the mineral substrate.

[0036] In embodiments, the at least one second circuit different from the first circuit comprises both a circuit for supplying a frequency-swept voltage signal for measuring the complex impedance and a radar circuit for generating a radar signal where both the frequency- swept voltage signal and the radar signal are used for determining properties of the mineral substrate.

[0037] In aspects, the technology disclosed relates to a for breaking a mineral substrate by passing a pulsed electrical current through the mineral substrate by means of a pulsed power drilling system comprising an arrangement for measuring properties of a mineral substrate including at last one circuit, a pulsed power generator comprising a first circuit for generating high voltage current pulses and a drill head comprising a plurality of electrodes each comprising a solid electrode portion configured to be connected to the pulsed power generator and to carry a discharge generated by the pulsed power generator, the method comprising:

[0038] - positioning the drill head so that the plurality of solid electrode portions are at least in proximity of a surface of the mineral substrate,

[0039] - measuring, by the arrangement for measuring properties of the mineral substrate, properties of the mineral substrate, wherein said measuring includes the use of at least one of the solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator, and wherein said measuring involves the use of at least one second circuit of the at least one circuit of the arrangement for measuring properties of a mineral substrate different from the first circuit,

[0040] - generating, by the pulsed power generator, a high voltage current pulse, and - passing the high voltage current pulse between a first electrode portion and a second electrode portion via the mineral substrate.

[0041] In certain aspects, the technology disclosed relates to a method for measuring properties of a mineral substrate by use of a pulsed power drilling system for breaking the mineral substrate including a pulsed power generator comprising a first circuit for generating high voltage current pulses and a drill head comprising a plurality of electrodes each comprising a solid electrode portion configured to be connected to the pulsed power generator and to carry a discharge generated by the pulsed power generator, the method comprising:

[0042] - providing the pulsed power drilling system with an arrangement for measuring properties of the mineral substrate,

[0043] - positioning the drill head so that the plurality of solid electrode portions are at least in proximity of a surface of the mineral substrate,

[0044] - measuring, by the arrangement for measuring properties of the mineral substrate, properties of the mineral substrate, wherein the measuring includes the temporary use of at least one of the electrodes that is also configured to carry a discharge generated by the pulsed power generator, and wherein the measuring involves the use of at least one second circuit of the arrangement for measuring properties of a mineral substrate that is a different circuit from the first circuit for generating high voltage current pulses,

[0045] - generating, by the pulsed power generator, a high voltage current pulse, and

[0046] - passing the high voltage current pulse between a first electrode portion and a second electrode portion via the mineral substrate.

[0047] In embodiments, the arrangement for measuring properties of the mineral substrate is measuring properties of the mineral substrate at a different time instant from when the first circuit of the pulsed power generator is generating high voltage current pulses.

[0048] In embodiments, the above step of measuring is comprising: supplying, by use of the second circuit different from the first circuit, at least one of a voltage and a current used for measuring the resistance or complex impedance between the solid electrode portions of at least two of the electrodes among the plurality of electrodes via the mineral substrate.

[0049] In embodiments, the above step of measuring is comprising: supplying, by use of the second circuit different from the first circuit, a frequency-swept voltage signal used for measuring the complex impedance between the solid electrode portions of at least two of the electrodes among the plurality of electrodes via the mineral substrate.

[0050] In embodiments, the drill head comprises at least three electrodes each comprising a solid electrode portion and the step of measuring is comprising measuring the complex impedance between at least two different combinations of electrodes via the mineral substrate where the at least two combinations of electrodes include at least three electrodes of the drill head, and wherein the measuring further includes applying a frequency-swept voltage signal supplied by the second circuit between the respective pair of solid electrode portions and continuously measuring the resulting current to determine the complex impedance for the respective pair of electrodes.

[0051] In embodiments, the arrangement for measuring properties of the mineral substrate comprises a circuit for generating radar signals which is configured to be electrically connected to at least one of the electrodes of the drill head is configured to be temporarily connected to a circuit for generating radar signals is configured to also function as an antenna for transmitting radar signals, and wherein said measuring comprises:

[0052] - generating, by the circuit for generating radar signals, radar signals,

[0053] - transmitting, from at least one electrode configured to be connected to the circuit for generating radar signals, the radar signals in the direction of the mineral substrate, and

[0054] - receiving reflected waves of the transmitted radar signals, wherein the reflected waves are used, by a measurement unit of the arrangement for measuring properties of the mineral substrate, for determining properties of the mineral substrate. In embodiments, the pulsed power drilling system comprises a pulsed power drilling tool including a pulsed power generator and a drill head, and the arrangement for measuring properties of the mineral substrate comprises at least one electrical circuit for supplying at least one of a current, a voltage and a radar signal to at least one solid electrode portion of the drill head for measuring properties of the mineral substrate where the at least one electrical circuit is physically separated from the electrical circuit used by the pulsed power drilling tool for generating high voltage current pulses for breaking a mineral substrate. The high voltage current pulse generator may then be arranged and configured to generate high voltage current pulses that pass between two of electrodes of the drill head via a fluid volume extending from a solid electrode portion of at least one of the electrodes of the drill head to a surface of the mineral substrate, for example via two fluid volumes extending from their respective electrode and the surface of the mineral substrate.

[0055] In embodiments, the solid electrode portion of at least one of the electrodes among the plurality of electrodes of the drill head that is configured to be electrically connected to the electrical circuit of the high voltage current pulse generator is also configured to be electrically connected to at least one electrical circuit used for measuring properties of the mineral substrate, for example the mineral substrate to be drilled. The solid electrode portion of the at least one electrode of the drill head that is used for breaking the mineral substrate by passing a high voltage current pulse between the solid electrode portion and another solid electrode portion of the drill head may then also be configured to function as at least one of a measurement electrode and a radar antenna for measuring properties of the mineral substrate to be drilled.

[0056] In embodiments, at least one of the at least one electrical circuit is part of an arrangement for measuring properties of the mineral substrate where the measurement arrangement is configured to apply at least one of a voltage and a current between at least two of the solid electrode portions of the drill head to thereby measure the complex impedance between the two solid electrodes via the mineral substrate where the measured complex impedance is indicting properties of the mineral substrate, for example properties of the mineral substrate to be drilled.

[0057] In embodiments, at least one of the at least one electrical circuit is part of an arrangement for measuring properties of the mineral substrate where the at least one electrical circuit is configured to generate a radar signal that is reflected by the mineral substrate and where the reflected radar signal is received by a detector of the arrangement to thereby measure properties of the mineral substrate, for example properties of the mineral substrate to be drilled.

[0058] In embodiments, the pulsed power drilling system further comprises a control system and a switching arrangement including at least one switch and the solid electrode portions of at least two of the plurality of electrodes of the drill head are arranged and configured to be electrically connected to an electrical circuit for applying at least one of a voltage and a current between at least two of the solid electrode portions of the drill head.

[0059] The solid electrode portion of the at least two electrodes among the plurality of electrodes may be further configured to also function as a measurement electrode for measuring the complex impedance between two solid electrode portions via the mineral substrate, for example via a fluid volume extending from the solid electrode portion of the at least one electrode to a surface of the mineral substrate.

[0060] In aspects, the present disclosure relates to a drill rig comprising a pulsed power drilling system according to any of the embodiments mentioned above. The drill rig may then be configured for breaking of a mineral substrate, such as in any one of rock drilling, concrete processing, mineral processing, and continuous mining.

[0061] Further advantages and advantageous features of the disclosure are disclosed in the following description and in the dependent claims.

[0062] BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In the following, the technology disclosed will be described in detail, with reference to exemplifying embodiments and to the enclosed drawings.

[0064] In the drawings:

[0065] Fig. 1 schematically illustrates a pulsed power drilling system according to an embodiment of the disclosure,

[0066] Fig. 2 schematically illustrates a pulsed power drilling system according to an embodiment of the disclosure, Fig. 3 schematically illustrates a pulsed power drilling system according to an embodiment of the disclosure,

[0067] Fig. 4 schematically illustrates a pulsed power drilling system according to an embodiment of the disclosure,

[0068] Fig. 5 is a flow-chart illustrating steps of a method according to an embodiment of the disclosure, and

[0069] Fig. 6 is a rock drilling machine, or drill rig, configured for comprising any of the pulsed power drilling system shown in Figs. 1, 2, 3 and 4.

[0070] The drawings show diagrammatic, exemplifying embodiments of the present disclosure and are thus not necessarily drawn to scale. It shall be understood that the embodiments shown and described are exemplifying and that the disclosure is not limited to these embodiments. It shall also be noted that some details in the drawings may be exaggerated in order to better describe and illustrate the disclosure. Like reference characters refer to like elements throughout the description, unless expressed otherwise.

[0071] DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE DISCLOSURE

[0072] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.

[0073] The present disclosure addresses at least some of the above-mentioned drawbacks associated with prior art pulsed power drilling tools by proposing a pulsed power drilling system comprising an arrangement for measuring properties of the mineral substrate to be drilled.

[0074] The basic concept of the invention is to measure properties of the material to be drilled by using the same electrodes that are also configured to carry a discharge between them via the mineral substrate. Thus, the same electrodes configured to carry a discharge may also be used in a separate step for measuring properties of the material to be drilled. The arrangement for measuring properties of the mineral substrate may then temporarily include at least one of the electrodes / solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator, where the arrangement for measuring properties of the mineral substrate further comprises at least one second circuit different from the first circuit. The at least one electrode / solid electrode portion of the arrangement for measuring properties of the mineral substrate is / are configured to be connected to the at least one second circuit when used for measuring properties of the mineral substrate. The at least one electrode / solid electrode portion is further configured to be connected to the first circuit generating high voltage current pulses when carrying a discharge generated by the pulsed power generator.

[0075] According to the technology disclosed, the arrangement for measuring properties of the mineral substrate is configured to measure properties of the mineral substrate at a different time instant from when the pulsed power generator is generating high voltage current pulses that are passing between two of the electrodes of the drill head via the mineral substrate for the purpose of breaking the mineral substrate. The arrangement for measuring properties of the mineral substrate may then be configured to use a separate and different energy source for measuring properties of the mineral substrate from the energy source used for generating the high voltage current pulses.

[0076] The technology disclosed may include at least one of measuring the impedance between chosen pairs of electrodes and transmitting a radar signal into the mineral substrate to determine properties of the material to be drilled. The proposed drilling system comprises a drill head with at least two electrodes, and typically at least three electrodes, each configured to carry a discharge. By measuring the impedance between several combinations of the at least three electrodes that are also configured to carry a discharge and / or detecting a reflected radar signal transmitted from at least one of the electrodes, a complete picture of the minerals of the drilled face can be found and a pair of electrodes for carrying a subsequent discharge, or several pairs of electrodes for carrying the respective discharge in a sequence of subsequent discharges, may be selected based on the measured properties.

[0077] In an embodiment, the technology disclosed may include measuring properties of the material to be drilled by applying a frequency-swept voltage signal between at least one of the electrodes that is also configured to carry a discharge. The pulsed power drilling system may then comprise a control system for controlling a switching arrangement so that a plurality of subsequent measurements may be performed by applying a frequency-swept voltage between two electrodes selected by the control system, for example a sequence of pairs of electrodes including at least three of the electrodes of the drill head. The properties of the mineral substrate determined from the plurality of measurement may then be used by the control system for determining between which two electrodes the optimal discharge can take place. As an example, the optimum pair of electrodes among at least three electrodes of the drill head may be selected by the control system to carry a subsequent discharge. This allows for maximizing rock destruction and minimizing equipment damage.

[0078] The at least three electrodes are then typically mutually electrically isolated from each other, and the equipment may further comprise a control system configured to obtain the impedance measurement data and then select the pair of electrodes that will carry a subsequent discharge based on the impedance measurement data. The same control system and switching arrangement used for controlling the generation of a high voltage current pulse that is passing between two electrodes via the mineral substrate may also be used for obtaining measurement data indicating properties of the material to be drilled.

[0079] Thus, the control system for controlling the switching arrangement may then also be configured to obtain the measurement data and then select the two electrodes that will carry a subsequent discharge at least partly based on properties of the mineral substrate determined from the measurements.

[0080] The pulsed power drilling system configured for passing a pulsed electrical current through a mineral substrate to break the mineral substrate may further comprise an arrangement for measuring properties of the mineral substrate comprising a second electrical circuit in the form of a voltage source circuit adapted to be used for measuring properties of the mineral substrate and configured to supply a frequency-swept alternating voltage signal. The pulsed power drilling system may then comprise a control system for controlling at least one switch so that the frequency-swept alternating voltage signal is temporarily applied between two of the electrodes of the drill head and the measurement system may be configured to measure the resulting current from the applied frequency-swept alternating voltage signal to determine the complex impedance and properties of the mineral substrate.

[0081] The arrangement for measuring properties of the mineral substrate may then comprise a measurement unit configured to determine the complex impedance between two electrodes of the drill head by applying a frequency-swept alternating voltage signal to the electrode(s) and continuously measuring the resulting current between the two electrodes. The at least one second circuit may then comprise a voltage source circuit configured to supply a frequency-swept alternating voltage signal. The pulsed power drilling system may then comprise a control system configured to control a switching arrangement and the opening and closing of at least one switch of the switching arrangement for temporarily connecting the two electrodes temporarily functioning as measurement electrodes to the voltage source circuit of the measurement unit to thereby allow for the frequency-swept alternating voltage signal supplied by the voltage source circuit to be applied to the two electrodes. The measurement unit may then be configured determine the complex impedance between the two electrodes based on the continuously measured current resulting from the frequency-swept alternating voltage applied across the two electrodes. The measurement unit may then be further configured to determine properties of the mineral substrate, for example properties of a mineral substrate to be drilled, based on the determined complex impedance between the two electrodes.

[0082] The technology disclosed may also relate to a pulsed power drilling system configured for passing a pulsed electrical current through a mineral substrate to break the mineral substrate and that comprises an arrangement for measuring properties of the mineral substrate comprising a second electrical circuit in the form of a circuit for generating a radar signal adapted to be used for measuring properties of the mineral substrate. The pulsed power drilling system may then further comprise a control system for controlling at least one switch so that the radar circuit is electrically connected to at least one of the electrodes of the drill head that is temporarily functioning as a radar antenna used for emitting the radar signal into the mineral substrate whose properties are measured.

[0083] The arrangement for measuring properties of the mineral substrate may then comprise a measurement unit configured to determine properties of the mineral substrate to be drilled by transmitting a radar signal via at least one of the electrodes of the drill head into the mineral substrate and detecting the radar signal reflected from the mineral substrate. The at least one second circuit may then comprise a radar circuit configured to generate a radar signal. The pulsed power drilling system may then comprise a control system configured to control a switching arrangement and the opening and closing of at least one switch of the switching arrangement for temporarily connecting at least one of the electrodes to the radar circuit to thereby allow for the radar signal generated by the radar circuit to be emitted by the at least one electrode temporarily functioning as a radar antenna. The measurement unit may then be configured determine properties of the mineral substrate, for example properties of a mineral substrate to be drilled, based on the detected radar signal reflected from the mineral substrate. In example embodiments, at least one of the electrodes of the drill head may then be configured to be used for detecting radar signals reflected from the mineral substrate and where the radar signal was transmitted from at least one of the other electrodes of the drill head. In certain embodiments, the arrangement for measuring properties of the mineral substrate comprises a separate detector unit configured to be used for detecting the radar signal reflected from the mineral substrate where the radar signal was transmitted from at least one of the electrodes of the drill head.

[0084] In embodiments, the arrangement for measuring properties of the mineral substrate is configured to measure properties of the mineral substrate by applying at least one of a frequency-swept alternating voltage signal and supplying a radar signal to at least one of the electrodes at a different time instant from when the circuit of the pulsed power generator is generating high voltage current pulses.

[0085] The arrangement for measuring properties of the mineral substrate may then be configured to use a separate and different energy source for measuring properties of the mineral substrate from the energy source used for generating the high voltage current pulses, for example a radar source and / or a voltage source separate from the energy source used for generating the high voltage current pulses.

[0086] The pulsed power generator may then comprise a first circuit for generating high voltage current pulse and a second circuit of the arrangement for measuring properties of the mineral substrate is configured to supply at least one of a voltage such as a frequency-swept alternating voltage signal that is temporarily applied between two of the electrodes among the plurality of electrodes of the drill head and used for measuring the resistance or impedance between the solid electrode portions of the two electrodes via the mineral substrate. The pulsed power generator may then comprise a first circuit for generating high voltage current pulse and a second circuit included in the arrangement for measuring properties of the mineral substrate that is configured to generate a frequency-swept alternating voltage signal and measure the resulting current to determine the complex impedance between at least two solid electrode portions via the mineral substrate.

[0087] In various embodiments, the pulsed power generator may comprise a first circuit for generating high voltage current pulse and a second circuit of the arrangement for measuring properties of the mineral substrate is configured to supply at least one of a voltage and a current that is applied between at least two of the solid electrode portions to thereby measure the resistance or complex impedance between the two solid electrodes via the mineral substrate.

[0088] The arrangement for measuring properties of the mineral substrate may be configured supply a frequency-swept alternating voltage that is adapted to be temporarily applied between a pair of electrodes to measure the complex impedance. The pulsed power drilling system is further configured to sequentially apply a frequency-swept alternating voltage supplied by the second circuit between at least two different combinations of electrodes via the mineral substrate in that the at least two combinations of electrodes include at least three electrodes of the drill head. The at least three electrodes may then be mutually electrically isolated from each other and the second circuit of the arrangement for measuring properties of the mineral substrate may be configured to be temporarily connected to the solid electrode portions of the at least three mutually electrically isolated electrodes when performing the at least two measurements of the complex impedance.

[0089] In certain embodiments, the at least one second circuit of the arrangement for measuring properties of the mineral substrate comprises a circuit for generating a radar signal which is configured to be electrically connected to at least one of the solid electrode portions included in the arrangement for measuring properties of the mineral substrate. The circuit for generating a radar signal may then be further configured to supply a radar signal that is transmitted via the electrode to be emitted by the solid electrode portion of the electrode temporarily functioning as an antenna for transmitting the radar signal in the direction of the surface of the mineral substrate for measuring properties of the mineral substrate. The arrangement for measuring properties of the mineral substrate may then comprise a receiving unit comprising a receiving circuit and detector configured for receiving reflected waves of the radar signal transmitted from the at least one solid electrode portion, where the reflected waves / radar signal are indicating properties of the mineral substrate. In certain embodiments, a solid electrode portion of at least one of the electrodes of the drill head may be configured to be used for receiving the reflected radar signal and the arrangement for measuring properties of the mineral substrate may comprise a receiving circuit and detector configured to receiving reflected waves of the transmitted radar signal indicating properties of the mineral substrate. The receiving circuit and detector for receiving reflected waves of the transmitted radar signal may then be physically separated from the at least one electrode / solid electrode portion transmitting the radar signal.

[0090] The technology disclosed relates to a drill rig comprising a pulsed power drilling system according to any one of the embodiments, where the drill rig is configured for breaking of a mineral substrate, such as in any one of rock drilling, concrete processing, mineral processing, and continuous mining.

[0091] The technology disclosed also relates to the use of a pulsed power drilling system according to any one of the above-mentioned embodiments, for breaking of a mineral substrate, such as in any one of rock drilling, concrete processing, mineral processing, and continuous mining.

[0092] According to aspects of the technology disclosed, the same electrodes, control system and switching arrangement used for the measuring properties of the material-to-be-drilled is also configured to obtain the measurement data and select which pair of electrodes that will carry a subsequent discharge at least partly based on the obtained measured properties of the material-to-be-drilled.

[0093] The control system of the pulsed power drilling system may further be configured to control the activation of the electrodes for a subsequent high voltage current pulse generated by the pulsed power generator based on the measurement data obtained by the arrangement for measuring properties of the mineral substrate. As an example, the control system may be configured to select the pair of electrodes for at least one subsequent high voltage current pulse generated by the pulsed power generator based on the measurement data obtained by the arrangement for measuring properties of the mineral substrate. The pulsed power drilling system may then comprise at least one switch and the control system may be configured to control the opening and closing of at least one switch to actively control the activation of the electrodes so that only the pair of electrodes selected for carrying a discharge for a subsequent high voltage current pulse are electrically connected to the circuit of the pulsed power generator.

[0094] The method according to the technology disclose may comprise the step of measuring, by the arrangement for measuring properties of the mineral substrate, properties of the mineral substrate, wherein the measuring includes the temporary use of at least one of the solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator for measurement purposes, and wherein the measuring further involves the use of at least one second circuit of of the arrangement for measuring properties of a mineral substrate different from the first circuit,

[0095] The step of measuring is performed at a different time instant from when the circuit of the pulsed power generator is generating high voltage current pulses.

[0096] The method may comprise the step of temporarily connecting at least one electrode / solid electrode portion of the drill head to a circuit of the arrangement for measuring so that the at least one electrode / solid electrode portion may be used for measuring properties of the mineral substrate.

[0097] The method may further comprises disconnecting the at least one electrode / solid electrode portion from the circuit after said measuring has been performed step, and connecting, the at least one electrode / solid electrode portion to the first circuit generating high voltage current pulses so that the at least one solid electrode portion can be used for carrying a discharge generated by the pulsed power generator.

[0098] The arrangement for measuring properties of the mineral substrate may then comprise a circuit for generating radar signals which is configured to be electrically connected to at least one of the solid electrode portions of the drill head. The measuring may then comprise the following steps:

[0099] - generating, by the circuit for generating radar signals, radar signals,

[0100] - transmitting, from at least one solid electrode portion having the radar device connected to it, the radar signals in the direction of the mineral substrate, and - receiving reflected waves of the transmitted radar signals for measuring properties of the mineral substrate.

[0101] The pulsed power drilling system may comprise a drill head with at least three electrodes, a control system, a switching arrangement and an arrangement for measuring properties of the mineral substrate that comprises a circuit for supplying a frequency-swept voltage signal configured to be electrically connected to at least one of the electrodes of the drill head. The measuring may then comprise the following steps:

[0102] - supplying, by the circuit, a frequency-swept voltage signal,

[0103] - applying, under the of the control system opening and / or closing at least one switch of the switching arrangement, the frequency-swept voltage signal between two of electrodes of the drill head,

[0104] - measuring, by the arrangement for measuring properties of the mineral substrate, the resulting current from applying the frequency-swept voltage signal between two of electrodes, and

[0105] - determining, by the arrangement for measuring properties of the mineral substrate, the complex impedance between the two electrodes to thereby determine properties of the mineral substrate.

[0106] The method may further comprise:

[0107] - recording, by the control system, measurement data indicating properties of the mineral substrate, wherein the recorded measurement data includes at least one of impedance measurements from measuring the complex impedance between at least two of the solid electrode portions via the mineral substrate and ground-penetrating measurements from a received reflected wave of a radar signal transmitted from at least one of the electrodes.

[0108] The pulsed power drilling system may further comprise a control system, and the method may further comprise the following steps:

[0109] - obtaining measurement data indicating properties of the mineral substrate, and - providing the control system with the obtained measurement data, wherein the measurement data includes at least one of impedance measurements from measuring the complex impedance between at least two of the solid electrode portions via the mineral substrate and ground-penetrating measurements from a received reflected wave of a radar signal transmitted from at least one of the electrodes.

[0110] In embodiments, the pulsed power drilling system further comprises a fluid supply system for supplying a shielding fluid to a region between the drill head and the mineral substrate. The shielding fluid may be any fluid that may serve to shield the fluid volume or volumes from each other and / or from one or more solid electrode portions of one or more other electrodes.

[0111] In certain embodiments, the pulsed power drilling system of the present disclosure further comprises at least one ionization device including at least one plasma generator. The pulsed drilling system may then further comprise a compressed gas supply system for supplying compressed gas to the at least one plasma generator. The at least one plasma generator may then be configured to ionize the compressed gas to generate a plasma, where the at least one ionized fluid volume is being formed by the plasma. The shielding fluid may then preferably be a different fluid than the fluid of the ionized fluid volumes. The shielding fluid may, e.g., be a flushing liquid, such as water, which is typically supplied during the drilling operation.

[0112] Optionally, the second solid electrode portion may be configured to be mechanically applied against the mineral substrate, wherein the at least one ionized first fluid volume is isolated from the second solid electrode portion. By mechanically applying the second solid electrode portion against the mineral substrate, correct positioning of the first solid electrode portion with respect to the mineral substrate is facilitated, i.e., positioning at a distance that will provide optimal conditions for creating the at least partly ionized fluid volume. The isolation between the ionized first fluid volume and the second solid electrode portion may be achieved as explained above.

[0113] Fig. 1 schematically illustrates an example embodiment of a pulsed power drilling system 100 configured for passing a pulsed electrical current through a mineral substrate 400 to break it and further configured for measuring properties of the mineral substrate 400. The pulsed power drilling system 100 comprises a pulsed power generator 110 for generating high voltage current pulses, and a drill head 120 extending in an axial direction of the pulsed power drilling system 100 between a front end 121, configured to be positioned near or at a surface of the mineral substrate 400, and a rear end 122. A pair of a first electrode 200 and a second electrode 200’ are arranged at the front end 121 of the drill head 120, protruding slightly therefrom.

[0114] The pulsed power generator 110 illustrated in Fig. 1 comprises a pulse transformer 112 in the form of a bank of capacitors, connected to an alternating current (AC) power supply 113 via a transformer 111. The pulsed power generator 110 comprises a first circuit (not shown) for generating high voltage current pulses and the electrodes 200 and 200’ may be connected to the pulsed power generator 110 by closing switches 114 and 114’ (currently open in Fig. 1). Using the switches 114 and 114’, a short high voltage pulse generated by use of the first circuit may be transferred to the electrodes 200 and 200’. The pulsed power generator is configured for generating pulses used for breaking the mineral substrate 400, such as nanosecond (ns) pulses to the electrodes 200 and 200’.

[0115] The first and second electrodes 200, 200’ may be galvanically connectable to the pulsed power generator 110 by means of switches 114, 114’. This is achieved by galvanically connecting the first electrode 200 to the switch 114, so that a high voltage current pulse generated by the first circuit of the pulsed power generator 110 passes to the first electrode 200, where a discharge is formed between the first electrode 200 and the mineral substrate 400 through the first fluid volume 210. As the switches 114, 114’ are closed, the high voltage current pulse thus passes between the first electrode 200 and the second electrode 200’ via the first fluid volume 210, the mineral substrate 400, and the second fluid volume 210’. As a result, a channel is formed in the mineral substrate 400 and the mineral substrate 400 is broken.

[0116] The pulsed power drilling system 100 illustrated in Fig. 1 further comprises an arrangement for measuring properties of the mineral substrate 150 including a measurement unit 190. The pulsed power drilling system 100 in Fig. 1 is configured so that the arrangement for measuring properties of the mineral substrate 150 temporarily includes also at least one of the electrodes 200 and 200’ of the drill head 120 in that the at least one of the electrodes 200 and 200’ is functioning as an antenna for emitting the radar signal generated during the measuring of properties of the mineral substrate 400.

[0117] In the example embodiment of a pulsed power drilling system 100 shown in Fig. 1, both the first electrode 200 and the second electrode 200’ are temporarily connected to a measurement unit 190 of the arrangement for measuring properties of the mineral substrate 150 via switches 115, 115’, where the measurement unit 190 comprises a second circuit for generating radar signals (not shown) . As the switches 115, 115’ are temporarily closed during a measurement phase, the radar signals generated by the second circuit are allowed to be transmitted to both the first electrode 200 and the second electrode 200’ and emitted from these two electrodes 200, 200’. The two electrodes 200, 200’ are thereby temporarily functioning as antennas for transmitting / emitting a radar signal generated by the second circuit into the mineral substrate 400. Thus, the arrangement for measuring properties of the mineral substrate 150 further temporarily includes the two electrodes 200, 200’ where each of the two electrodes 200, 200’ comprises a receiving circuit and a detector (not shown in Fig. 1) for receiving reflected waves of the radar signals transmitted from the two electrodes included in the arrangement for measuring properties of the mineral substrate 150. The reflected waves detected by the detector and receiving circuit of the respective electrode 200, 200’ are indicating properties of the mineral substrate 400. In the example embodiment shown in Fig. 1, each of the first electrode 200 and the second electrode 200’ comprises a receiving circuit and detector for receiving a radar signal reflected from the mineral substrate, i.e. reflected radar waves, and the measurement data obtained from the detection of the reflected radar signals is then transmitted or forwarded to the measurement unit 190. The measurement unit 190 is configured to determine properties of the mineral substrate at least partly based on the measurement data / reflected radar signals.

[0118] The pulsed power drilling system 100 illustrated in Fig. 1 further comprises an electronic control unit 160 for controlling operation of the pulsed power drilling system 100 in response to signals received from an external control unit 170, such as a control unit of a machine, e.g. drill rig, in which the pulsed power drilling system is provided. The electronic control unit 160 may include a microprocessor, a microcontroller, a programmable digital signal processor or another programmable device. Thus, the control unit 160 comprises electronic circuits and connections (not shown) as well as processing circuitry (not shown) for communicating with different parts of the drilling tool 100 as well as with the external control unit 170. For example, the control unit 160 may be configured for communicating with various sensors, devices, systems and control units of the pulsed power drilling system 100. In the embodiment shown in Fig. 1, the control unit 160 controls the switches 114, 114’.

[0119] The electronic control unit 160 may comprise modules in either hardware or software, or partially in hardware or software, and communicate using known transmission buses such a CAN-bus and / or wireless communication capabilities. The processing circuitry may be a general-purpose processor or a specific processor. The control unit 160 may comprise a non-transitory memory for storing computer program code and data. Thus, the skilled person realizes that the electronic control unit 160 may be embodied by many different constructions.

[0120] The first electrode 200 comprises a solid electrode portion (not shown) arranged at a front end of the electrode 200. The solid electrode portion may be made at least partially of electrically conductive material and may be either metallic or ceramic.

[0121] The example embodiment of a pulsed power drilling system 100 illustrated in Fig. 1 further comprises a fluid supply system 140 for supplying a shielding fluid, such as a flushing fluid, e.g., water, to a region between the drill head 120 and the mineral substrate 400 via a fluid conduit 141 having an outlet 142 located between the first and the second electrodes 200, 200’. The flushing fluid isolates the first fluid volume 210 from the second fluid volume 210’.

[0122] The same pulsed power drilling system 100 may be configured to use a combination of electrodes arranged around a perimeter of the drill head 120 and the outlet 142 of the shielding fluid conduit 141 may then by way of example be positioned at a center of the drill head 120, but a variety of different configurations are possible.

[0123] Fig. 2 schematically illustrates an embodiment of a pulsed power drilling system 100 configured for passing a pulsed electrical current through a mineral substrate 400 to break it and further configured for measuring properties of the mineral substrate 400. The pulsed power drilling system 100 in the embodiment shown in Fig. 2 has essentially the same features as the pulsed power drilling system 100 shown in Fig 1 , with the exceptions that only the first electrode 200 is currently connected to the second circuit for generating radar signals in Fig. 2 and that the pulsed power drilling system 100 in Fig. 2 further comprises a separate receiving unit 191 including a receiving circuit and detector (not shown) configured for receiving reflected waves of radar signal transmitted from at least one of the electrodes 200, 200’ (currently transmitted only from the first electrode 200 in Fig. 2). In the example embodiment shown in Fig. 2, the pulsed power drilling system 100 further comprises a separate receiving unit 191 for receiving a radar signal reflected from the mineral substrate, i.e. reflected radar waves, and the measurement data obtained from the detection of the reflected radar signals by the receiving unit 191 is subsequently transmitted / forwarded to the measurement unit 190. The measurement unit 190 is configured to determine properties of the mineral substrate 400 at least partly based on the measurement data / reflected radar signals received or obtained from the receiving unit 191.

[0124] Fig. 3 schematically illustrates an embodiment of a pulsed power drilling system 100 configured for passing a pulsed electrical current through a mineral substrate 400 to break it. The pulsed power drilling system in the embodiment shown in Fig. 3 comprises a pulsed power generator 110, which is schematically represented in Fig. 3 by a pulse transformer 112 in the form of a bank of capacitors and two electrodes 200, 200’, and an arrangement for measuring properties of the mineral substrate 150 that comprises a measurement unit 190. In the embodiments shown in Fig. 3, the electrodes 200, 200’ are configured to be connected to a first circuit (not shown) of the pulsed power generator 110 via their respective switches 114 and 114’ (the switches 114 and 114’ in Fig. 3 are open so the electrodes 200, 200’ are currently not connected to the pulsed power generator 110. The two electrodes 200, 200’ shown in Fig. 3 are further configured to be connected to the measurement unit 190 of the arrangement for measuring properties of the mineral substrate 150 via their respective switches 115 and 115’. The measurement unit 190 comprises a second circuit (not shown) configured to supply a frequency-swept voltage signal that is applied between the two of electrodes 200, 200’ to measure the complex impedance between the two electrodes 200, 200’. The resulting current from the applied frequency-swept voltage signal is measured / obtained by the measurement unit 190. The measurement unit 190 is configured to determine the complex impedance from the current resulting from the applied frequency-swept voltage signal to thereby, in turn, determine properties of the mineral substrate 400 to be drilled. In the example embodiment of a pulsed power drilling system 100 illustrated in Fig. 3, the two electrodes are temporarily connected to the measurement unit 190 via their respective switches 115, 115’. Since the switches 115 and 115’ are temporarily closed in Fig. 3, a frequency-swept voltage signal generated by the second circuit of the measurement unit 190 is allowed to be applied between the two electrodes 200, 200’. The two electrodes 200, 200’ in Fig. 3 are further allowed and configured to rotate around their own longitudinal axis to thereby be positioned at different positions in the same drilling / measurement plane so that several measurements of the complex impedance may be performed for different positions of the two electrodes 200, 200’ in the same measurement / drilling plane prior to generating, by the first circuit of the pulsed power generator 110, a high voltage current pulse for breaking the mineral substrate 400.

[0125] Fig. 4 schematically illustrates an embodiment of a pulsed power drilling system 100 configured for passing a pulsed electrical current through a mineral substrate 400 to break it. The pulsed power drilling system 100 in the embodiment shown in Fig. 4 further comprises a pulsed power generator 110, which is schematically represented in Fig. 4 by a pulse transformer 112 in the form of a bank of capacitors. The pulsed power drilling system 100 in Fig. 4 is configured so that two of the electrodes among the three electrodes 200, 200’, 200” may be simultaneously connected to a first circuit (not shown) of the pulsed power generator 110 via their respective switches 114, 114’, 114”.

[0126] The pulsed power drilling system 100 in Fig. 4 further comprises a control unit 160 and an arrangement for measuring properties of the mineral substrate 150 that comprises a measurement unit 190. The arrangement for measuring properties of the mineral substrate 150 may temporarily further include two of the electrodes 200’, 200” among the three electrodes 200, 200’, 200” of the drill head. The two electrodes 200, 200’ in Fig. 4 may be temporarily connected to a second circuit (not shown) of the measurement unit 190.

[0127] The second circuit of the measurement unit 190 is configured to supply a frequency-swept voltage signal that is temporarily applied between the two electrodes 200, 200’ simultaneously connected to the measurement unit 190 via their respective switches 115, 115’. Hence, in the example embodiment of a pulsed power drilling system 100 shown in Fig. 4, only the electrode to the right 200 and the middle electrode 200’ are configured to be temporarily (and simultaneously) connected to the second circuit of the measurement unit 190 via their respective switches 115, 115’.

[0128] The control unit 160 of the embodiment in Fig. 4 is configured to control the opening and closing of switches 114, 114’, 114” to thereby control which pair of electrodes are currently connected to the first circuit configured to generate a high voltage current pulse to carry a discharge. The control unit 160 in Fig. 4 is further configured to control the opening and closing of switches 115, 115’ to thereby control when the two electrodes 200, 200’ are connected to the second circuit of the measurement unit 190 so that the frequency-swept voltage signal may be temporarily applied between the two electrodes 200, 200’. Each of the two electrodes 200, 200’ may not be simultaneously connect to both the first circuit of the pulsed power generator 110 and the second circuit of the measurement unit 190.

[0129] The measurement unit 190 of the of the arrangement for measuring properties of the mineral substrate 150 in Fig. 4 comprises a second circuit (not shown) configured to supply a frequency-swept voltage signal that is applied between two of the three electrodes 200, 200’, 200” during measurement and the resulting current is measured by the measurement unit 190. The resulting current from the applied frequency-swept voltage signal is used by the measurement unit 190 to determine the complex impedance from the current resulting from the applied frequency- swept voltage signal to thereby, in turn, determine properties of the mineral substrate 400 to be drilled.

[0130] The technology disclosed further relates to the use of a pulsed power drilling system according to any of the embodiments of a pulsed power drilling system shown in Figs. 1 to 4 for breaking of a mineral substrate, such as in any one of rock drilling, concrete processing, mineral processing, and continuous mining.

[0131] An example method for breaking a mineral substrate by passing a pulsed electrical current through the mineral substrate by means of any of embodiments of a pulsed power drilling system is illustrated in Fig. 5. The method comprises the following actions / steps:

[0132] 510: Position drill head, i.e. positioning the drill head so that the plurality of solid electrode portions are at least in proximity of a surface of the mineral substrate; 520: Measure properties of rock, i.e. measuring, by the arrangement for measuring properties of the mineral substrate, properties of the mineral substrate, wherein said measuring includes the use of at least one of the solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator, and wherein said measuring involves the use of at least one second circuit of the at least one circuit of the arrangement for measuring properties of a mineral substrate different from the first circuit;

[0133] 530: Generate high voltage (HV) current pulse, i.e. generating, by the pulsed power generator, a high voltage current pulse; and

[0134] 540: Pass pulse between electrodes, i.e. passing the high voltage current pulse between a first electrode portion and a second electrode portion via the mineral substrate.

[0135] Fig. 6 illustrates schematically a drill rig 500, or rock drilling machine, comprising a drilling system 100 as shown in any of Figs. 1 to 4, drilling a hole 401 in a mineral substrate 400 in the form of a rock. The drill rig 500 comprises the alternating current (AC) power supply 113 for powering the pulsed power generator 110. It further comprises the compressed gas supply system 130 and the fluid supply system 140. A hydraulic, pneumatic, or electrically actuated arm 510 for at least vertical positioning of the drilling tool 100 is provided, such as in response to signals from one or more position sensors (not shown) or similar sensing the distance between the electrodes and the mineral substrate surface. The drill rig 500 further comprises ground engaging members 520 for moving the drill rig 500 in a direction parallel with the rock 400.

[0136] It is to be understood that the present disclosure is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

Claims

CLAIMS1. A pulsed power drilling system configured for passing a pulsed electrical current through a mineral substrate to break the mineral substrate, the pulsed power drilling system comprising:- a pulsed power generator comprising a first circuit for generating high voltage current pulses,- a drill head comprising a plurality of electrodes each comprising a solid electrode portion configured to be connected to the pulsed power generator and to carry a discharge generated by the pulsed power generator so as to allow for a high voltage current pulse generated by the pulsed power generator to pass between the respective electrode portion of two electrodes among the plurality of electrodes of the drill head via the mineral substrate, and- an arrangement for measuring properties of the mineral substrate, wherein the arrangement for measuring is including at least one of the solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator, and wherein the arrangement for measuring properties of the mineral substrate further comprises at least one second circuit different from the first circuit.

2. The pulsed power drilling system according to claim 1, wherein the at least one solid electrode portion of the arrangement for measuring properties of the mineral substrate is / are configured to be connected to the at least one second circuit when used for measuring properties of the mineral substrate, and wherein the at least one solid electrode portion is further configured to be connected to the first circuit generating high voltage current pulses when carrying a discharge generated by the pulsed power generator.

3. The pulsed power drilling system according to any of claims 1 and 2, wherein the arrangement for measuring properties of the mineral substrate is configured to measure properties of the mineral substrate at a different time instant from when the first circuit of the pulsed power generator is generating high voltage current pulses.

4. The pulsed power drilling system according to any of claims 1 to 3, wherein the arrangement for measuring properties of the mineral substrate is configured to use a separate and different energy source for measuring properties of the mineral substrate from the energy source used for generating the high voltage current pulses.

5. The pulsed power drilling system according to any of claims 1 to 4, wherein a circuit of the at least one second circuit is configured to supply at least one of a voltage and a current used for measuring the impedance between the solid electrode portions of two electrodes among the plurality of electrodes via the mineral substrate.

6. The pulsed power drilling system according to any of claims 1 to 5, wherein a circuit of the at least one second circuit of the arrangement for measuring properties of the mineral substrate is configured to generate an alternating current for measuring the complex impedance between at least two solid electrode portions via the mineral substrate.

7. The pulsed power drilling system according to any of claims 1 to 6, wherein the arrangement for measuring properties of the mineral substrate is configured to apply at least one of a voltage and a current between at least two of the solid electrode portions to thereby measure the complex impedance between the two solid electrodes via the mineral substrate.

8. The pulsed power drilling system according to any of claims 1 to 7, wherein the drill head comprises at least three electrodes each comprising a solid electrode portion and a second circuit of the arrangement for measuring properties of the mineral substrate is configured to measure the complex impedance between at least two different combinations of pairs of solid electrode portions via the mineral substrate in that the at least two combinations of pairs include the solid electrode portions of the at least three electrodes.

9. The pulsed power drilling system according to claim 8, wherein the at least three electrodes are mutually electrically isolated from each other and the arrangement for measuring properties of the mineral substrate includes thesolid electrode portions of the at least three mutually electrically isolated electrodes.

10. The pulsed power drilling system according to any of claims 1 to 9, wherein the at least one second circuit of the arrangement for measuring properties of the mineral substrate comprises a circuit for generating a radar signal which is configured to be electrically connected to at least one of the solid electrode portions included in the arrangement for measuring properties of the mineral substrate, and wherein the circuit for generating a radar signal is further configured to apply a radar signal to the at least one solid electrode portion and the at least one solid electrode portion is configured to also function as an antenna for transmitting a ground-penetrating radar signal generated by the circuit for generating a radar signal in the direction of the surface of the mineral substrate for measuring properties of the mineral substrate.

11. The pulsed power drilling system according to claim 10, wherein the arrangement for measuring properties of the mineral substrate comprises a receiving circuit configured for receiving reflected waves of radar signals transmitted from the at least one solid electrode portion included in the arrangement for measuring properties of the mineral substrate, and wherein the reflected waves are indicating properties of the mineral substrate.

12. The pulsed power drilling system according to claim 11, wherein the at least one solid electrode having the radar signal applied to it also comprises the receiving circuit configured for receiving reflected waves of the transmitted radar signal indicating properties of the mineral substrate.

13. The pulsed power drilling system according to claim 11, wherein the receiving circuit for receiving reflected waves of the transmitted radar signal is physically separated from the at least one electrode transmitting the radar signal.

14. A method for breaking a mineral substrate by passing a pulsed electrical current through the mineral substrate by means of a pulsed power drilling system comprising an arrangement for measuring properties of a mineralsubstrate including at last one circuit, a pulsed power generator comprising a first circuit for generating high voltage current pulses and a drill head comprising a plurality of electrodes each comprising a solid electrode portion configured to be connected to the pulsed power generator and to carry a discharge generated by the pulsed power generator, the method comprising:- positioning the drill head so that the plurality of solid electrode portions are at least in proximity of a surface of the mineral substrate,- measuring, by the arrangement for measuring properties of the mineral substrate, properties of the mineral substrate, wherein said measuring includes the use of at least one of the solid electrode portions that is also configured to carry a discharge generated by the pulsed power generator, and wherein said measuring involves the use of at least one second circuit of the at least one circuit of the arrangement for measuring properties of a mineral substrate different from the first circuit,- generating, by the pulsed power generator, a high voltage current pulse, and- passing the high voltage current pulse between a first electrode portion and a second electrode portion via the mineral substrate.

15. The method according to claim 14, wherein the arrangement for measuring properties of the mineral substrate is measuring properties of the mineral substrate at a different time instant from when the first circuit of the pulsed power generator is generating high voltage current pulses.

16. The method according to any of claims 14 and 15, said step of measuring is comprising: supplying, by use of said at least one second circuit, at least one of a voltage and a current used for measuring the impedance between the solid electrode portions of at least two of the electrodes among the plurality of electrodes via the mineral substrate.

17. The method according to claim 14 to 16, wherein said drill head comprises at least three electrodes each comprising a solid electrode portion and said step of measuring is comprising measuring the complex impedance between at least two different combinations of pairs of solid electrode portions via themineral substrate where the at least two combinations of pairs include the solid electrode portions of the at least three electrodes, and wherein said measuring includes applying, by use of said at least one second circuit, at least one of a voltage and current between the respective pair of solid electrode portions.

18. The method according to any of claims 14 to 17, wherein the arrangement for measuring properties of the mineral substrate comprises a circuit for generating radar signals which is configured to be electrically connected to the at least one solid electrode portion included in the arrangement for measuring properties of the mineral substrate and the at least one solid electrode portion configured to be connected to the circuit for generating radar signals is configured to also function as an antenna for transmitting radar signals, and wherein said measuring comprises:- generating, by the circuit for generating radar signals, radar signals,- transmitting, from the at least one solid electrode portion configured to be connected to the circuit for generating radar signals, the radar signals in the direction of the mineral substrate, and- receiving reflected waves of the transmitted radar signals, wherein the reflected waves are used for measuring properties of the mineral substrate.

19. Use of a pulsed power drilling system according to any one of claims 1-13 for breaking of a mineral substrate, such as in any one of rock drilling, concrete processing, mineral processing, and continuous mining.

20. A drill rig comprising a pulsed power drilling system according to any one of claims 1- 13 for breaking of a mineral substrate, such as in any one of rock drilling, concrete processing, mineral processing, and continuous mining.

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