Abstract: The invention relates to a wedging arrangement to plug a blast hole accommodating an explosive charge. The wedging arrangement comprises a body comprising a first part and a second part arranged to angularly slide relative to each other. Each of the first and second parts defines a holding arrangement for holding the first and second parts relative to each other. The wedging arrangement is configurable between a default configuration in which the holding arrangement holds the first and second parts relative to each other, and a stressed configuration in which the body is subjected to external stress forces thereby causing the holding arrangement to be disengaged to allow the first and second parts to angularly slide relative to each other, in use to locate and lock the wedging arrangement in place within the blast hole in order to plug the blast hole and contain the blast energy resulting from the explosive charge being detonated.

Abstract: Systems and methods for a flow activated choke device that is activated by the choke device directly interacting with the flow of fluid in an upstream direction. More specifically, a choke device formed of chain like materials that is configured to be extended in a first mode and compacted in a second mode, wherein the choke device moves from the first mode to the second mode responsive to an upward fluid flow rate being greater than a flow rate threshold.

Abstract: A stemming plug (60) for stemming a blast hole in a mine is disclosed. The plug has first and second wedge-shaped members (62?, 62) manufactured from a suitable plastics material. The first wedge-shaped member (62?) has a first sloping face received in sliding relationship with a matching face of the second wedge-shaped member (62) wherein, in use, when the first wedge-shaped member (62?) is positioned nearest to an explosive material in the blast hole it has a larger surface area facing the explosive material than the second wedge-shaped member (62). In use, when a Shockwave from initiation of the explosive material in the blast hole encounters the first wedge-shaped member (62?) it acts as a piston, sliding on the second wedge-shaped member (62) so that both wedge-shaped members exert diametrically opposed forces against the wall of the blast hole to lock the plug (60) in place. The two wedge-shaped members (62?, 62) may be substantially identical, thus significantly simplifying the manufacturing process.

Abstract: A cartridge (1) is provided which includes an elongate tube (3) having a central body (5) that is closed at each end (11, 13) and containing a gas producing substance (30) therein. The tube (3) is made from a plastics material that is capable of outward deformation and a band (15) of an elastically deformable material is provided about the tube (3) adjacent each closed end. The tube (3) is configured such that internal pressure in the tube (3) caused by initiation of the gas producing substance (30) results in outward deformation of the body (5) and each band (15) and subsequent rupture of the body (5) prior to the closed ends being ruptured or opened.

Abstract: A covering that has a means for support, a means for abutment to a wall, and a means for retaining a sensing element. The covering includes a body portion and a perimeter portion with a plurality of radially extending fins. Fins with or without boss are useful for abutment to a wall or surface. One or more means for retaining positioned in the interior of the body, are useful for fixedly positioning or holding a sensing element. The covering may be position on or into a hole and optionally includes additional elements for function and use, such as reinforcing members on the radially extending fins, a central hub, and a spool position around the hub.

Abstract: A fireworks igniter system and method for safely igniting fuse-type fireworks including a handheld igniter module and a remote control module. An igniter head at the proximal end of the igniter module includes a heater element and fuse clamp slide which receives and biasingly molds the fuse against the heater element. A microprocessor in the igniter module includes an infrared receiver and an igniter module actuator. The remote control module includes an infrared emitter and a remote control module actuator, the infrared emitter emitting a coded IR signal in response to activation of the actuator. The IR signal is sensed by the infrared receiver to activate the igniter module actuator and deliver electric current to the heater element sufficient to ignite the fuse.

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: 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: A covering that has a means for support, a means for abutment to a wall, and a means for retaining a sensing element. The covering includes a body portion and a perimeter portion with a plurality of radially extending fins. Fins with or without boss are useful for abutment to a wall or surface. One or more means for retaining positioned in the interior of the body, are useful for fixedly positioning or holding a sensing element. The covering may be position on or into a hole and optionally includes additional elements for function and use, such as reinforcing members on the radially extending fins, a central hub, and a spool position around the hub.

Abstract: A target discrimination system monitors an acceleration switch signal to determine an impact of a projectile on a target. During a sample period of approximately 1.0 milliseconds, the system repeatedly samples the acceleration switch signal, compares the sampled acceleration sensor signal with a reference voltage, and sets a comparator data output to logic one if the sampled signal exceeds the reference voltage. Otherwise, the comparator data output is set to logic zero. The system counts the instances that comparator data output equals logic one during the sample period and executes a selected delay. The selected delay is approximately 50 milliseconds if the counted number of instances exceeds a predetermined threshold of approximately two-thirds of the samples and, otherwise, the selected delay is approximately 10 milliseconds. The selective delay enables target discrimination and selective detonation of a projectile.

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: A tool for use in a wellbore has an activation assembly, which has a support structure and a reactive layer on the support structure. The reactive layer is formed of a pyrotechnic material. The activation assembly also includes an electrically conductive protective layer covering the reactive layer to protect the reactive layer from electrical discharge. The tool further includes a component to be activated by the activation assembly.

Abstract: Methods and apparatus for detonating explosives or igniting flammables are disclosed. According to some embodiments of the invention, initiators include an initiating component holding an exploding bridgewire (EBW) or an exploding foil initiator (EFI) and a flammable component housing thermite. An end of the flammable component mates with a corresponding end of the initiating component. A method of initiating the explosives or flammables includes connecting the two components to assemble the initiator, disposing the initiator proximate the explosives or flammables, and activating the initiator to cause ignition of the thermite that then initiates the explosives or flammables. Additionally, a non-explosive kit for the initiator includes the two components with the EBW or EFI initially spaced from the thermite within the flammable component to make the initiator disarmed until final assembly thereof.

Abstract: A rock breaking cartridge (10) which includes a tubular body (12), spaced inner and outer second caps (14 and 16) inside the tubular body (12), a propellant (20) inside the tubular body (12) between the caps (14 and 16), a radially expansible stemming device (30) inside the tubular body (12) spaced from the inner cap (14), and a filler (34) between the inner cap (14) and the stemming device (30).

Abstract: Methods and apparatus for detonating explosives or igniting flammables are disclosed. According to some embodiments of the invention, initiators include an initiating component holding an exploding bridgewire (EBW) or an exploding foil initiator (EFI) and a flammable component housing thermite. An end of the flammable component mates with a corresponding end of the initiating component. A method of initiating the explosives or flammables includes connecting the two components to assemble the initiator, disposing the initiator proximate the explosives or flammables, and activating the initiator to cause ignition of the thermite that then initiates the explosives or flammables. Additionally, a non-explosive kit for the initiator includes the two components with the EBW or EFI initially spaced from the thermite within the flammable component to make the initiator disarmed until final assembly thereof.

Abstract: A tool for use in a wellbore has an activation assembly, which has a support structure and a reactive layer on the support structure. The reactive layer is formed of a pyrotechnic material. The activation assembly also includes an electrically conductive protective layer covering the reactive layer to protect the reactive layer from electrical discharge. The tool further includes a component to be activated by the activation assembly.

Abstract: A firing head for a perforating gun includes a detonating block having a first end and a second end, with the second end being structured and arranged so as to be located adjacent to a detonation material. A central passage extends through the detonating block from the first end to the second end. A detonator is located and restrained in the passage so as to be adjacent to the detonating material. At least one venting passage extends from the central passage to an exterior of the detonating block.

Abstract: A chemically inflated gas bag for mining is provided. This gas bag includes a modified PVA bag that contains sodium bicarbonate and an HDPE bag that contains acetic acid. The PVA bag and the HDPE bag are contained within a nylon/PE bag. Preferably, when the HDPE bag is broken, the flow of acetic acid onto the PVA bag is controlled by a second bag having small holes therein surrounding the HDPE bag, allowing the gas bag to be lowered into a borehole before it inflates. Another aspect of the present invention is a method of making this gas bag. This method includes pouring diluted acetic acid into an HDPE bag, putting sodium bicarbonate into a PVA bag, sealing these bags, and placing these bags within a nylon/PE bag. The gas bag is folded in such a manner as to easily inflate and completely seal the borehole.

Abstract: A method for making a chemically inflatable gas bag using technical grade acetic acid, water, and sodium bicarbonate is provided. The method includes pouring diluted acetic acid into an HDPE bag, putting sodium bicarbonate into a PVA bag, sealing these bags, and placing these bags within a nylon/PE bag. The method further includes folding the gas bag in such a manner so that it easily inflates and completely seals the borehole.

Abstract: Reinforced borehole plugs useful in the presplitting and blast removal of earth formations, the improvements provided by the invention comprising inflatable devices intended to support stemming, explosives and the like at suspended locations within a borehole to produce desired blast results. The borehole plugs of the invention comprise inflatable sport balls such as are used on playgrounds as toys and which are reinforced according to the invention to maintain inflation within a borehole, a characteristic which playground balls can only inconsistently provide. The borehole plugs of the invention are preferably inflatable through use of valve structures which permit pumping of an inflating fluid into the plugs once the plugs are respectively suspended at desired locations within boreholes prior to filling the boreholes in whole or in part with stemming and/or explosives and the like.

Abstract: An electronic module for a detonator, the module comprising an electronic circuit (4, 5, 6) encapsulated in a mass of hardened resin (7) in which there terminates at least one inlet conductor (8) and from which there extend two outlet conductors forming a detonator ignitor line (9), the mass of resin (7) being received in a tubular housing (1) which extends beyond the mass of resin (7) adjacent to the ignitor line (9) to define a cavity (11), the outlet conductors of length greater than the depth of the cavity forming an ignitor line (9) short circuited outside the mass of resin inside the cavity (11), which cavity is provided with a removable end cap (12).

Abstract: This invention relates to a device for accurately delivering a ballistically stable, monolothic projectile at repeatable velocities to a specified target using an explosive event without causing deformation or fragmentation of the projectile. In its most preferred embodiment, the invention will deliver a projectile using an explosive event without substantial deformation or altering of the geometric shape of the projectile. This invention was specifically developed as a preferred device to render safe the firing train of the fuze mechanism of unexploded ordnance (UXO) to dispose of the UXO more safely.

Abstract: A method of stemming a borehole (6) includes the steps of placing a first layer (16) of stemming in the borehole, placing a spherical body (20) in the borehole on top of the layer (16), the body being relatively incompressible and a diameter slightly smaller than the diameter of the borehole, and placing a second layer (18) of stemming in the borehole over the body. The stemming (16, 18) may be placed in the borehole either in direct contact with an explosive (8), or spaced from it by a gas bag (24) or the like form a deck (22). In accordance with an alternate application, the stemming layers (16, 18) may be placed in the borehole prior to placement of an explosive material such that it serves as backfill. Preferably, the stemming includes crushed rock and drill cuttings such as those produced during formation of the borehole. However, other available materials may also be used such as gravel.

Abstract: A method of blasting cap-sensitive, non-nitroglycerine-sensitized explosives and an initiating assembly for use in the method are provided. The method comprises initiating a column of the explosives by directing two radial/forward shock forces from an initiator assembly substantially simultaneously along the column of the explosives towards each end of the column. The initiating assembly of the invention comprises at least two initiators assembled side-by-side so that their explosive ends are opposite. A moulded plastics holder (6) for holding two blasting caps (1, 8) in the required spatial relationship is also described.

Abstract: An explosive activated assembly for repairing a heat exchange tube in which a grooved metal casing is inserted into the tube to be repaired and has a plurality of projections extending from the outer surface thereof. A force-transmitting member extends within a bore formed in the casing and contains an explosive member so that, upon detonation of the explosive member, the force-transmitting member and the casing are expanded radially outwardly to drive the projections against the tube. A booster is located within the casing and adjacent the charge and is activated by a transfer cord connected to an externally located detonator. The casing is formed with an extension that extends over a portion of the transfer cord and has a hole through which the cord extends to contain the debris and vapor caused by the explosion.

Abstract: A device for breaking monolithic structures or pulsating by inducing pressure in a liquid filling a pre-drilled hole in the monolithic structure to be shattered comprises a tubular housing having a cavity for accommodating an explosive charge. Provided in the lower portion of the housing is a partition of an elastomeric material and a pipe serving to locate the device in a mouth of the hole and be filled with the liquid so as to form an air gap between the partition and the surface of the liquid. In order to retain the device inside the hole a means is provided connected to the housing and fashioned as an inertia element disposed outside the hole.

Abstract: A passive detonation cut-off device for a solid line of explosives operates by directionally controlling the detonation pressure of an accidental detonation wave of an explosives line and by using this directionally controlled detonation pressure to sever the explosives line to prevent further propogation of the detonation wave. The device comprises a body having two through holes extending through the body and at least one blast hole connecting the through holes and extending from one of the through holes to the outside of the body.

Abstract: An explosive plug for blocking tubes comprises a tubular metal body closed at one end by a solid head and having at the other end a surface-contact region containing at least two spaced apart charges actuable by a detonator. The metal body when placed in a tube to be blocked is so arranged that the surface-contact region is coaxial with but at a distance from the tube so that successive explosion of the charges causes the surface-contact region to be radially spattered against the interior of the tube thus producing a reliable metal weld or welds extending along a substantial part of the end region of the tube.