Abstract: The present invention concerns an explosive material charging device (1) and a method of positioning the explosive material charging device (1) in a borehole (3). The explosive material charging device (1) comprises a top anchor unit (5) and a bottom anchor unit (7) each configured to engage the borehole wall (8), an expandable tube member (11) arranged between the top anchor unit (5) and the bottom anchor unit (7) and configured to be charged with explosive material (40), the bottom anchor unit (7) comprises a backflow prevention valve device (13) configured to prevent the explosive material (40) to flow out from the expandable tube member (11), wherein the backflow prevention valve device (13) is openable for permitting a charging hose (15) to enter the expandable tube member (11) for reaching the interior of the top anchor unit (5).

Abstract: Systems for forming or extending a tunnel or shaft within a working surface may include a ram accelerator assembly for accelerating a projectile into geologic material to weaken a region of the geologic material. A cutting tool may then be used to remove the weakened material. A collection assembly may be used to move debris away from the working surface while the projectile and cutting operations are performed to enable generally continuous use of the system. The number of projectiles that are accelerated and the rate at which projectiles are used may be controlled based on characteristics of the geologic material and the rate at which created debris may be removed.

Abstract: A method and apparatus for controlled charging of blasting boreholes with a flowable/pourable explosive, in particular in open-cast mining, includes: providing a radar head with at least one radar unit operated in a non-rock penetrating frequency range; arranging the radar head on a pulling element; introducing the radar head into the borehole in that the radar head is lowered into the blasting borehole in an arrangement at the pulling means from an upper aperture opening of the blasting borehole; and detecting at least one measurement value comprising a base distance of the radar head from the blasting borehole base and/or a charge level distance to determine the charge level of the explosive in the blasting borehole; and/or comprising the shape of the jacket section over at least a portion of the depth of the blasting borehole by means of the operation of at least one of the radar units.

Abstract: The application relates to a charging system for charging at least one charging hole. The system comprises a charging boom, sensors of the boom, a movement mechanism of the boom, a charging head of the boom for charging the at least one hole, and a controller for controlling the boom. The sensors obtain location information relating to the boom. The controller defines locations of the charging head in a co-ordinate system of the boom on the grounds of at least the obtained location information. The controller also operates the movement mechanism to move the charging head between the defined locations in accordance with precalculated movements.

Abstract: A reasonable millisecond time control method for excavation blasting of a tunnel is provided, and includes: acquiring physical mechanical parameters to establish a millisecond blasting model, and designing four dimensions blasting parameters of explosive quantity, hole number, inter-hole millisecond and inter-row millisecond; simulating, based on the millisecond blasting model, a blasting process of an explosive package using blasting parameters to obtain a blasting vibration curve; obtaining single-hole blasting vibration waveforms, solving a vibration synthesis curve through a vibration synthesis theory; comparing the vibration synthesis curve with the blasting vibration curve to obtain a coupling relationship of blasting parameters; determining a target group of explosive quantity and hole numbers, determining a target millisecond through the coupling relationship of blasting parameters, and relating a millisecond blasting control strategy to control, and it is used for tunneling project to reduce cut blas

Abstract: A control method of a drill jumbo is provided. The drill jumbo includes a pre-splitting arm, a drill arm, and a chamber. The pre-splitting arm includes a positioning device, a fixing buckle, a longer rod, an electric telescopic rod, and a water injection opening. The chamber includes a constant pressure valve, an excitation circuit, and a port. A computer controls the positioning device to perform positioning, afterwards, the fixing buckle is opened, the telescopic rod is started, the longer rod is jacked into a position in the hole, and oil is injected into a hydraulic expansion capsule. After blocking of the hole is completed, water is injected into the water injection opening. The port is opened to inject a mixed-phase fluid. The port is closed, the excitation circuit is started, and after a pressure rises to a set value, the constant pressure valve is opened.

Abstract: A block cave has a draw column height of at least 450 meters, a caved volume, a single extraction level and no undercut level, a plurality of drawbells extending upwardly from the extraction level to the caved volume, and a plurality of pillars separating the drawbells and supporting the rock mass above the extraction level. Each drawbell has a drawbell height of at least 25 meters. Each drawbell has the following profile when viewed from a direction perpendicular to a drawbell drive in the extraction level: a throat section having opposed parallel side walls extending upwardly from the extraction level, a tapered section above the throat section, and an undercut section above the tapered section.

Abstract: The present invention relates to a method and related devices for carrying out TBM excavation and expansion blasting, which uses a blast protector and a cart to expand a pilot tunnel by blasting after the pilot tunnel has been formed; and which specifically includes: a step of forming a pilot tunnel; a step of forming a horizontal or vertical blast hole; a step of installing a blast protector within the pilot tunnel; a step of blasting the upper and lower halves of the pilot tunnel to expand the upper and lower halves; and a step of removing the debris formed during the blasting of the upper and lower halves, by dumping the debris into a cart. Accordingly, the rail and cable are protected from the debris formed during the blasting, and working efficiency is improved.

Abstract: A method of blasting rock at an underground blast site in which boreholes (11a, b, c) are drilled in a rock mass 10 from a drive defining face 12, each borehole is loaded with at least one charge of explosive material (13a-c, 14a-c, 15a-c), at least one detonator is placed in operative association with each charge, and a sequence of at least two initiation events is conducted to blast the rock mass, in each of which only some of the charges are initiated, by sending firing signals to only the detonators associated with said charges and in which each initiation event is a discrete user-controlled initiation event. In one of the at least two initiation events a stranded portion of the rock mass such as a pillar is created that has already been drilled and charged, and the stranded portion of the rock mass is blasted in a subsequent one or more of the at least two initiation events without personnel accessing said stranded portion.

Abstract: The subject disclosure relates to determining an optimum orientation for perforations around the circumference of a subsurface borehole and optimum wellbore fluid initiation pressure for hydraulic fracturing in anisotropic formations.

Abstract: An explosive cartridge comprising: an explosive composition; a deactivating agent that is capable of desensitising the explosive composition; and a barrier element that prevents contact between the explosive composition and the deactivating agent and that is adapted to be at least partially removed on use of the explosive cartridge.

Abstract: In certain implementations, a method of manufacturing electrically conductive nanodiamond particles involves providing at least one type of carbon-containing explosive material and at least one type of non-explosive material; wherein the non-explosive material contains at least one or more than one element or species other than nitrogen that serve as a nanodiamond dopant; mixing the carbon containing explosive material with the non-explosive material; detonating the mixture under conditions of negative oxygen balance in the presence of a cooling medium; purifying the product of detonation from incombustible impurities; and carrying out additional processing for activation or enhancement of electrical conductance. This abstract is not to be considered limiting, since other embodiments may deviate from the features described in this abstract.

Abstract: A perforating system is disclosed having a perforating gun containing a plurality of radially-oriented shaped charges disposed along the longitudinal axis of the gun. Each charge, when detonated, produce a jet whose penetration velocity exceeds the acoustic velocity of the formation (i.e., target) material to be perforated. A method of operating such a perforating system is also provided, as is a shaped charge having the described characteristics.

Abstract: A method of blasting plural layers of material (38, 40, 42, 44) in a blastfield (16) that reduces the amount of mechanical excavation required to expose a lower layer of material. The method includes using rows of equally spaced blastholes (18, 20, 22, 24) that pass through all of the layers and additional intermediate rows of blastholes (26, 28) that pass down only through top layer (40). Each blasthole is capped with stemming material and includes one or more decks of explosives material (46) and detonators (48), with air decks or inert stemming (45) separating adjacent explosives decks (46). The detonators in layer (40) are detonated first in order from row (18) rearwards to throw a substantial amount of the blast material from layer (40) forwardly of free face (12) onto floor (34).

Abstract: The invention provides a method of preparing a blast hole which method comprises the steps of: drilling a blast hole; placing explosives in the blast hole; filling the blast hole with a stemming material comprising a cement composition and water wherein the weight ratio of water to solids content of the stemming material is at least about 1:1.

Abstract: A tunnel excavation technique using a water jet. A water jet system includes a moving unit movable back and forth with respect to an area to be blasted for tunnel excavation, an articulated robot arm mounted on the moving unit, a water jet nozzle which ejects high-pressure water and an abrasive toward an area to be excavated, and a control unit which controls the moving unit, the articulated robot arm and the water jet nozzle. A free face having a predetermined depth is formed of the area to be excavated in the direction in which the tunnel is to be excavated using the water jet system. Since the blasting is performed after the free face is formed, blast vibration can be effectively restricted.

Abstract: A process for real-time classification of materials, the process including: conducting laser induced breakdown spectroscopy on the material (LIBS), wherein at least one second laser pulse is directed to the plume so as to selectively energize only a portion of the plume; measuring optical emissions from the energized portion of the plume; and assessing the elemental composition of the material on the basis of the optical emissions from the excited portion of the plume; wherein the energized portion of the plume is substantially smaller than the entire plume so that the measured optical emissions are relatively independent of the size of the entire plume and hence are relatively independent of the optical absorption and vaporization characteristics of the material, thereby allowing a more accurate assessment of the elemental composition of the material than if the assessment was based on the optical emissions from the entire plume.

Abstract: A method of mining a mineral deposit includes setting a plurality of explosive charges at spaced pre-blast locations in the deposit, wherein at least selected pre-blast locations also carry respective markers that are such that the post-blast location of at least a useful proportion will be detectable after explosion of the charges. After the charges are exploded to fragment the deposit, the post-blast locations of certain of the markers are detected to obtain an indication of the relative positions of selected components of the mineral deposit after the fragmentation of the deposit by the exploding of the charges. Also disclosed is a method utilising a plurality of markers arranged to emit a detectable signal after blast fragmentation, and detecting the post-blast locations by triangulation techniques employing a plurality of receiver detectors. A further aspect proposes the use of secondary explosive charges as post-blast markers.

Abstract: The present invention relates to ammonium nitrate fuel oil mixtures, and includes compositions comprising (a) ammonium nitrate, (b) a fuel component, (c) a functionalized polymer component, and (d) an oil-soluble anionic surfactant, wherein the mixture of components (b), (c) and (d) form a gel that will not readily flow. The compositions of the present invention provide improve fuel retention and/or water resistance properties, particularly when the compositions use low quality porous prills of ammonium nitrate.

Abstract: A method of block cave mining comprising excavating undercut tunnels (21) at an undercut level; drilling undercut blast holes (25) through the undercut tunnel roofs and setting and detonating explosive charges in those holes to blast rock above the undercut tunnels to initiate the formation of broken rock caverns (26) above the undercut tunnels (21); excavating extraction level tunnels (22) at an extraction level below the undercut level; drilling drawbell blast holes (33) upwardly from the extraction level tunnels at selected drawbell locations toward the broken rock caverns (26) and setting and detonating explosive charges in those holes to blast drawbells (32) through which broken rock falls down into the extraction level tunnels (22); and progressively removing such fallen rock from the drawbell locations through the extraction level tunnels (22); wherein some of the excavation is done mechanically by tunnel boring machinery.

Abstract: A method of small-charge blasting, a rock drilling unit and a front guide to be used therein. By means of a rock drill machine provided in the rock drilling unit, a hole is first drilled into a material to be excavated and, subsequently, a drilling tool is pulled out of the hole. Next, one or more propellants comprising a propellant charge are fed to the bottom of the hole through a propellant feed channel provided in connection with a feed beam. Then, the hole is sealed and the propellant is ignited, whereupon a high gas pressure is generated, which causes fractioning in the material to be excavated. During the feeding and ignition of the propellant, the rock drill machine is kept in a parallel direction with respect to the hole.

Abstract: The invention provides a method of preparing a blast hole which method comprises the sequential steps of: drilling a blast hole; placing explosives in the blast hole; filling the blast hole with a stemming material comprising a cement composition and water wherein the weight ratio of water to solids content of the stemming material is at least about 1:1.

Abstract: A method of mining a mineral deposit includes setting a plurality of explosive charges at spaced pre-blast locations in the deposit, wherein at least selected pre-blast locations also carry respective markers that are such that the post-blast location of at least a useful proportion will be detectable after explosion of the charges. After the charges are exploded to fragment the deposit, the post-blast locations of certain of the markers are detected to obtain an indication of the relative positions of selected components of the mineral deposit after the fragmentation of the deposit by the exploding of the charges. Also disclosed is a method utilizing a plurality of markers arranged to emit a detectable signal after blast fragmentation, and detecting the post-blast locations by triangulation techniques employing a plurality of receiver detectors. A further aspect proposes the use of secondary explosive charges as post-blast markers.

Abstract: A method of charging explosives in a substantially vertical blast borehole, with a loading density reduced in relation to that corresponding to the complete fill up of the borehole diameter. The method includes the step of introducing a charging hose in fluid connection with a nozzle into an end opening of the vertical blast borehole. The charging hose and nozzle are then moved along the blast borehole along a travel direction at a controlled rate. As the nozzle is being moved, an explosive emulsion is forced though the nozzle at a controlled pumping rate such that the emulsion is sprayed by the nozzle laterally relative to the travel direction, in an arc formation extending around an axis of the nozzle, which axis is parallel to the travel direction, and onto an inner wall of the blast hole. The pumping rate and the controlled moving rate are adjusted so as to form a coherent string of the explosive emulsion exiting from the nozzle, whereby the string only partially fills up the blast borehole diameter.

Abstract: A rock-fracturing mining explosive element; said explosive element subjected to an initial spreading against a target surface on impact of said explosive element with said target surface; said explosive element so constructed as to control the rate of spreading and compression against said surface prior to detonation.

Abstract: A cylindrical casing (18) has first and second ends (33 and 31), the first end (33) being closed. The casing (18) encloses an accelerant (22) disposed adjacent the first end (33), at least one stemming mechanism (21), and a fuse (14 or 14?) extending from the accelerant (22) out of the second end (31) of the cylindrical casing (18). The cartridge (12) is made of a rupturable cylindrical casing (18) with accelerant (22) and self-stemming mechanism (22) inserted therein. A method of breaking hard (R) materials involves detonating a self-stemming cartridge (12) disposed in a borehole (B).

Abstract: A method for small-charge blasting, and a rock drilling unit used therein. By means of a rock drilling machine of the rock drilling unit, a drill hole is first drilled into material to be excavated, after which one or more cartridges comprising a propellant charge are fed through a drilling tool onto the bottom of the drill hole. The drilling unit comprises a cartridge feed station, which is separate from the rock drilling machine and from which the cartridges may be fed into a longitudinal channel in the drilling tool.

Abstract: An open cast mining method includes sinking a blasting borehole (14) for receiving an explosive charge into a ground body (12) which is to be mined, taking an initial measurement of one or more borehole conditions, including at least a temperature inside a bottom half (14.1) of the borehole (14), and loading the borehole (14) with a base explosive charge (28) only if the initial measurement of all of the one or more measured borehole conditions are within predefined limits indicating that the borehole (14) will not be subject to uncontrolled detonation of the base explosive charge (28). The one or more borehole conditions, including at least said temperature, are further measured and monitored after the base explosive charge (28) has been loaded. An alarm signal external of the borehole (14) is provided if any of the one or more measured borehole conditions are not within predefined limits so that there is a risk of uncontrolled detonation of the explosive charge (28).

Abstract: A method of blasting rock at an underground blast site in which boreholes (11a, b, c) are drilled in a rock mass (10) from a drive defining face (12), each borehole is loaded with at least one charge of explosive material (13a-c, 14a-c, 15a-c), at least one detonator is placed in operative association with each charge, and a sequence of at least two initiation events is conducted to blast the rock mass, in each of which only some of the charges are initiated, by sending firing signals to only the detonators associated with said charges and in which each initiation event is a discrete user-controlled initiation event. In one of the at least two initiation events a stranded portion of the rock mass such as a pillar is created that has already been drilled and charged, and the stranded portion of the rock mass is blasted in a subsequent one or more of the at least two initiation events without personnel accessing said stranded portion.

Abstract: A method for fracturing a solid material is disclosed. The method comprises boring at least one bore hole in the solid material, the bore hole having a bottom and an open top. Reactive materials capable of an exothermic reaction to produce a liquid and a gas are introduced into the bore hole. The bore hole is then sealed at the open top. The exothermic reaction is then initiated to produce the liquid and the gas. The pressures generated by the liquid and gas in the bore hole result in fracturing of the solid material.

Abstract: An inexpensive bullet-shaped plug is shown for use in a blasting hole containing water in the bottom thereof, which plug permits dry powder to be used above the waterline rather than more expensive wet powder. After the blasting holes are drilled, if water accumulates in the bottom thereof, the bullet-shaped plug with a center weight is dropped into the hole, which bullet-shaped plug floats on the water. Small rocks are dropped on top of the bullet-shaped plug causing upper tentacles to flare out to engage the wall of the blasting hole. Dry powder is then loaded into the blasting hole on top of the bullet-shaped plug. A cap is inserted a distance below the surface of the blasting hole. Thereafter, a series of similar blasting holes are blown at one time to create debris that can be removed or further processed.

Abstract: An electronic blasting capsule which includes a housing which contains a propellant, a fuse, a sensor for detecting the position of the housing in a capsule delivery path, an energy arrangement for obtaining energy from an external energy source, and a controller, responsive to the sensor and the energy arrangement, for firing the fuse to initiate the propellant.

Abstract: A method of breaking rock which includes the steps of drilling a hole in the rock using a drill rod; leaving the drill rod in the hole; using water flow to direct a propellant charge into the hole through a passage in the drill rod; and at a leading end of the drill rod, firing the propellant charge with, at least, the drill rod and water in the hole and passage providing a stemming function.

Abstract: A process for extracting ore from a vein (10) comprises drilling spaced-apart boreholes (16) directly in the vein (10). The boreholes (16) are enlarged using thermal fragmentation generally up to the boundaries between the vein and surrounding waste. A blasthole (18) is then drilled in the vein between the thermally enlarged boreholes (17) for placement of explosive. The explosive is fired to break the ore between the enlarged boreholes (17). The enlarged boreholes (17) act as weakening regions to direct the blasting effect and minimize dilution.

Abstract: An open cast mining method includes sinking a blasting borehole (14) for receiving an explosive charge into a ground body (12) which is to be mined, taking an initial measurement of one or more borehole conditions, including at least a temperature inside a bottom half (14.1) of the borehole (14), and loading the borehole (14) with a base explosive charge (28) only if the initial measurement of all of the one or more measured borehole conditions are within predefined limits indicating that the borehole (14) will not be subject to uncontrolled detonation of the base explosive charge (28). The one or more borehole conditions, including at least said temperature, are further measured and monitored after the base explosive charge (28) has been loaded. An alarm signal external of the borehole (14) is provided if any of the one or more measured borehole conditions are not within predefined limits so that there is a risk of uncontrolled detonation of the explosive charge (28).

Abstract: A method of mining a valuable metal or material in an ore body is described. The method comprises the steps of: a) placing a cushion in a stope whereby the cushion creates a void into which fragmented rock can expand during subsequent blasting operations for a second or subsequent panel; and, b) maintaining the void until blasting operations occur whereupon the void is caused to collapse to accommodate fragmented ore generated during blasting operations.

Abstract: A cylindrical casing (18) has first and second ends (33 and 31), the first end (33) being closed. The casing (18) encloses an accelerant (22) disposed adjacent the first end (33), at least one stemming mechanism (21), and a fuse (14 or 14) extending from the accelerant (22) out of the second end (31) of the cylindrical casing (18). The cartridge (12) is made of a rupturable cylindrical casing (18) with accelerant (22) and self-stemming mechanism (22) inserted therein. A method of breaking hard (R) materials involves detonating a self-stemming cartridge (12) disposed in a borehole (B).

Abstract: The present invention provides a method and formulation for the creation of a diamond-carbon bearing material of varying particle sizes. The material is a detonation by-product of explosive formulations that employ carbon dioxide as the oxidizing agent and a material, such as powdered magnesium, as the fuel for such detonation.

Abstract: A method of mining a mineral deposit includes setting a plurality of explosive charges at spaced pre-blast locations in the deposit, wherein at least selected pre-blast locations also carry respective markers that are such that the post-blast location of at least a useful proportion will be detectable after explosion of the charges. After the charges are exploded to fragment the deposit, the post-blast locations of certain of the markers are detected to obtain an indication of the relative positions of selected components of the mineral deposit after the fragmentation of the deposit by the exploding of the charges. Also disclosed is a method utilising a plurality of markers arranged to emit a detectable signal after blast fragmentation, and detecting the post-blast locations by triangulation techniques employing a plurality of receiver detectors. A further aspect proposes the use of secondary explosive charges as post-blast markers.

Abstract: A process for extracting ore from a vein (10) comprises drilling spaced-apart boreholes (16) directly in the vein (10). The boreholes (16) are enlarged using thermal fragmentation generally up to the boundaries between the vein and surrounding waste. A blasthole (18) is then drilled in the vein between the thermally enlarged boreholes (17) for placement of explosive. The explosive is fired to break the ore between the enlarged boreholes (17) . The enlarged boreholes (17) act as weakening regions to direct the blasting effect and minimize dilution.

Abstract: Methods of blasting rock are disclosed and claimed in which blast holes are arranged in group of 2 to 7 blast holes. Within each of the groups, adjacent columns of explosive material (12) are actuated within 5 ms of one another Initiation of blasting between the respective groups occurs at least 8 ms after completion of initiation of an adjacent group. Initiation devices (13, 24) may be located at the lower end, upper end or both ends of the respective blast holes, depending on the stress field that is intended to be generated within the rock. As a result, environmental stresses such as ground vibrations are reduced, and the efficiency of rock fragmentation are increased.

Abstract: A method for controlling the initiation of an electronic detonator when located in surrounding ground, the method comprising the steps of: measuring the actual spatial position of the said detonator in relation to one or more adjacent detonators; and calculating the time of initiation of the said detonator based upon its actual spatial position.

Abstract: A method of blasting in which rock pile profile associated with a blast field is controlled by precise control of the detonation delay times between and/or within individual blastholes in the blast field, in combination with the control of one or more other blast parameters. One or more of the blast parameters may by blasthole geometry, explosive charge or blast initiation location.

Abstract: A drill hole (350) extends into rock to be blasted. A blasting accessory (310) includes a container portion (312) for holding a predetermined volume of stemming material, and a spacer (330) for spacing the stemming material a predetermined distance from a surface, e.g. a blind bottom of the drill hole. The container portion has a top (320) surrounded by a dilatable, inverted skirt forming a seal (342), and forms a support for a blasting substance like an explosive.

Abstract: Apparatus for breaking rock includes a cartridge with a base and a wall which extends from the base, the base and the wall forming an enclosure, a propellant inside the enclosure and means for igniting the propellant, and wherein at least the wall is made from a malleable material adapted to reinforce the wall of a hole in the rock in which the cartridge is located.

Abstract: An earth boring apparatus for sinking shafts and removing shaft material from the shaft, the apparatus having at least two decks; hydraulic means for allowing movement of the decks relative to one another; releasable anchoring means associated with the decks for engaging walls of the shaft to secure the apparatus in a stationary position; whereby the releasable anchoring means of one of the decks engages the wall while the releasable anchoring means of the other deck is released from the wall to allow motion of the other deck along the shaft, in cooperation with the hydraulic means. The apparatus also includes guide means for forcing a bucket for hoisting shaft material from the shaft along a predetermined path, and an in-stage cut-boom drill.

Abstract: A tool (12) has a body (14) with a barrel (18) having opposing threaded and fitted openings (30 and 28). An actuator pin tube (26), for slidably engaging an actuator pin (38) having a tip (40) opposing a retention head (42), extending from the fitted opening (30). A spring assembly (24), disposed in the barrel (18), has a hammer guide (44) engaged in the threaded opening (28) with a hammer (46) slidably engaged therein, a handle mechanism (55) disposed at one end and a spring retainer (52) disposed adjacent the other end of the hammer (46) before a hammerhead (51), and a spring (54) engaged between the hammer guide (44) and the spring retainer (52). A release mechanism (56) engages the hammer (46). A kit (108) containing the tool (12) and a method of operating the tool (12) involving drilling and cleaning a borehole, inserting a cartridge and tool therein, and detonating the load remotely using a pull cord.

Abstract: A blasting arrangement (10) includes drillholes (30) in a rock mass (20). Blind ends (32) are drilled to a desired level and, if necessary, are adjusted as shown at (62) to said level. Each hole (30) is plugged by means of a plug (42), which is protected by non flammable buffer material (44), at a level (40) spaced from the end (32). Explosive (50) is charged above the level (40) and the hole is tamped, shown at (60). The holes are detonated desirably by detonators (52), forcing the plugs (42) downwardly and compressing air in chambers (34) above the ends (32). The weakest part of each hole, around the end (32), is split causing a three dimensional zone of weakness at the level of the ends (32). Air forced into the zone of weakness causes a fracture zone (70) at that level, inhibiting propagation of blasting shock waves and protecting the material underneath the level of the ends (32).

Abstract: An electrode for a crusher and a crusher capable of increasing energy utilized for crushing are obtained. The electrode 1 for a crusher comprises a central conductor (12, 17) extending along a central axis and having an outer peripheral surface, an insulating member (13, 18) arranged on the outer peripheral surface of the central conductor (12, 17) and a peripheral conductor (15) arranged to enclose the insulating member (13, 18). The peripheral conductor (15) includes a first conductor (14a) and a second conductor (14b) arranged at a space from the first conductor (14a) in the extensional direction of the central axis.

Abstract: Apparatus 10 for fracturing a hard material 24 includes a loading head 12 provided with a guide tube 14 for receiving a cartridge 16 containing a charge of energetic material. A flexible elongated conduit 26 is advanced and retracted through the tube 14 via a reel 88. The conduit 26 is also in communication with a stemming loader 30 which holds a supply of particulate stemming material. Tube 14 is supported by a carriage 70 which is able to slide along a member 52 by operation of a rod 76 and cylinder 78. A motor 60 is also coupled to the member 52 to effect rotation of the member 52 and thus tube 14 about an axis A which is parallel to a hole 18 drilled in the material 24. By appropriate operation of the motor 60 and rod 76, the tube 14 can be moved into and out of alignment with the hole 18. When the tube 14 is moved into alignment with the hole 18, cartridge 16 is loaded into the tube 14 and pushed through the tube 14 into the hole 18 by advancing the conduit 26.