Abstract: A tunnel driving method using a drill carriage provided with plural number of drill booms having drifters. According to a preferred embodiment, while the drill carriage is placed before a bench, the charging cages are moved to mark blasting holes and rock bolt holes for an upper portion. While the drill carriages are moved backward with a predetermined length, the charging cages are moved to insert the rock bolts for the upper portion. Simultaneously, the charging cages are operated in a lower portion to bore blasting holes for the lower portion. Then, the charging cages are operated to charge the blasting holes for the upper portion and the lower portion with dynamite for blasting so that the facing is broken and a new facing is formed. Subsequently, after first and second operation of concrete shooting, the above continuous operation is performed repeatedly.

Abstract: A blasting agent is disclosed for use in a borehole having a pressure resistant closure. The blasting agent is used in combination with a primary initiating system comprised of a detonator and an initiator for the detonator. The blasting agent is preferably a semi-fluid explosive material having a predetermined sensitivity. The sensitivity is related to the borehole diameter and the initiating system's strength, wherein the blasting agent upon initiation is transformed into explosive products by means of reaction front which consumes substantially all the blasting agent as the reaction front passes through the blasting agent. The reaction front has an average velocity of propagation of between 200 meters/second and 1,000 meters/second for at least 30% of the total length of blasting agent located in the borehole. Another aspect of the invention is a method of blasting wherein the average velocity of propagation of the explosive front in the blasting agent is in a range of between 200 m/sec and 1,000 m/sec.

Abstract: An explosive device receives signals specifying a unique communications address for use in a blasting circuit and a required blasting delay. The device has an electric igniter, but no independent power source which might cause accidental detonation. In an address and delay setting mode, when the device is being handled by a blaster, a unipolar signal is transmitted to the device to charge only a control power supply for general communications. In a blasting mode, a bipolar signal is transmitted to charge both control and igniter power supplies. A security code must, however, be transmitted to enable charging of the igniter power supply. Prior to detonation, each explosive device in a blasting circuit responds to a calibration signal by generating a timing circuit test count. A blasting machine processes nominal delays and test counts, and transmits adjusted delays to synchronize operation.

Abstract: A connection between the ends of two discrete signal transmission devices allows signal propagation between the ends of the devices. The ends of the devices are axially aligned at a close distance from one another within an alignment sleeve. A length of heat-shrink tubing having a sealant on its inner surfaces is placed over the alignment sleeve and the ends of the devices. The tubing is heated and provides axially compressive and radially compressive forces on the alignment sleeve and device ends thereby providing a high tensile strength connection between the device ends.

Abstract: A method of charging waterlogged boreholes with water-resistant particulate explosive material, comprises inserting a pneumatic line with upwardly directed nozzles at the lower end thereof and a material supply line into a borehole, blowing compressed air through the pneumatic line such that at least a portion thereof is directed through the nozzles to form a substantially water-free air pocket around the lower end of the supply line, supplying particulate explosive material through the supply line to a charging zone in the vicinity of the lower end thereof, and gradually withdrawing said line as the borehole fills up with explosive material.

Abstract: A unitary dual firing assembly includes a high explosive detonation cord with ends, each actuable by a different firing mechanism. The ends of the high explosive detonation cord are adjacent respective bulkhead membranes which, if broken, are effective to transfer a shockwave to detonate the high explosive cord. An intermediate section of the high explosive cord is effective to detonate perforating gun apparatus. A hydraulic firing head is located adjacent the membrane at one end of the high explosive detonating cord, while a mild explosive detonating cord is located adjacent the membrane at the other end of the high explosive detonating cord. An upper end of the mild explosive detonating cord terminates in a stem cap assembly which is responsive to an impact for detonating the high explosive cord, via a lower end of the mild explosive detonating cord. Mechanical or fluid inputs can thus be applied to reliably detonate one or the other of the firing mechanisms to trigger the perforating gun.

Abstract: A gas generating type tool includes a propellant charge having an axially extending passage receiving therein an ignition tube containing a quantity of easily ignited, fast burning powder. The propellant and ignition tube are separately handled and/or transported until ready to run into the well. The tube slides easily into the propellant passage. The propellant passage is at least about 12% larger in cross-section than the ignition tube and not more than about 55% larger in cross-section. In circular cross-sections, the propellant passage is at least about 6% greater in diameter and not more than about 25% greater in diameter.

Abstract: A process for the impact healing of inner discontinuities or defects in the surface area of a cast workpiece where the defects are localized comprises locating an explosive charge on the surface of the workpiece over the inner discontinuities or defects and detonating the explosive charge.

Abstract: In the preferred embodiment of the new and improved perforating apparantus that is described herein, a set of end closure members are cooperatively arranged to be inserted into the open ends of a length of typical piping and expanded radially outwardly into contact with the rough and irregular internal wall surface in each end of the pipe. Anchor members and sealing members are arranged on each and closure member for releasably securing and sealingly engaging these end closure members in the ends of the pipe when the end closure members are respectively expanded outwardly so that no machining operations are required to prepare the internal wall surfaces of the pipe before it can be employed as an expendable perforating carrier.

Abstract: A positive displacement explosive base dosing pump is provided with a drive motor 14 and has an outlet 22 connected via a flexible hose 24 to a lance 70. The lance 70 has a mixing device 72 therein and a reciprocable positive displacement gassing solution dosing pump has an outlet connected via a flexible conduit 54 to the lance and feeding into the lance upstream of the mixing device 72. The invention involves using the base dosing pump 12 to pump explosive base from a supply 78 along the hose 24 to the lance 70 while the gassing solution dosing pump 16 simultaneously pumps gassing solution from a supply 56 along the flexible conduit 54. The conduit 54 leads the solution into the lance 70 upstream of the mixing device 72 whereby the explosive base is mixed with the solution, so that a mixture issues from the lance 70 which become sensitized after reaction has taken place between the base and solution.

Abstract: A perforating gun includes a base strip having an angular cross section, the base strip being a single unitary structure and essentially comprising at least two longitudinally disposed surfaces, a first surface and a second surface, a first plurality of capsule charges being connected to the first surface and a second plurality of capsule charges being connected to the second surface and interleaved with the first plurality of capsule charges, thereby phasing the capsule charges in the perforating gun. Since the gun utilizes capsule charges, good penetration into the formation is achieved. Due to the cross sectional configuration of the base strip, the phased capsule charges, when mounted on the strip, will easily fit within a tubing string previously used by non-phased capsule charge perforating guns.

Abstract: A booster for high efficiency initiation of an explosive material comprising a body portion having substantially tapered sides and a substantially flat interface surface at the larger end of the body portion extending generally laterally thereof for contacting the explosive material. A plurality of passageways may be formed in the booster to receive a means for detonating same. When compared with traditional cylindrical boosters of either equal weight or equally sized interface surfaces, the disclosed booster resulted in shorter run-up distance and a more effective release of explosive energy. Although numerous geometric configurations of the booster are disclosed, a presently preferred embodiment thereof takes the shape of a conical frustum, the larger planar surface of which is to be oriented as the interface surface toward the explosive material to be detonated.

Abstract: A process for preparing a gas bubble sensitized explosive composition. The present process comprises preparing an explosive composition comprising a water-in-oil emulsion and mechanically entraining gas bubbles into the explosive composition. Low viscosity emulsion explosives are able to be sensitized by this process. There is a preference for wax free emulsions to be used. The process is applicable to emulsion explosives comprising ammonium nitrate particles. By providing a process for the mechanical entrainment of stable gas bubbles we allow explosive compositions to be sensitized on-site by readily available mixing means.

Abstract: An improved well perforating device comprising a body member in the form of a cylindrical pressure vessel containing shaped explosive charges positioned normal to the longitudinal axis of the body member. The perforating device body is systematically shaped externally at the foci of the hollow cones so that both focused and wall expansion energy of the explosive energy of detonation is sufficiently controlled to prevent excessive deformation of the outer diameter of the body member.

Abstract: A shaped charge carrier assembly includes a thin wall carrier having a charge opening disposed therethrough for freely receiving a shaped charge therein. A deformable retaining device is integrally formed with the thin wall carrier adjacent a periphery of the charge opening. The deformable retaining device allows the shaped charge to initially be freely received in the charge opening, but subsequently retains the shaped charge in the charge opening upon deformation of the deformable retaining device.

Abstract: The invention provides methods and apparatus useful primarily in the presplitting and blast removal of earth formations, the improvements according to the invention involving the use of inflatable devices suspended in boreholes used in shattering earth formations. The inflatable devices of the invention can be of various shapes and are provided with valves to allow a fluid such as air to be pumped into each device on placement of the device at a desired location in a borehole. The inflatable devices are preferably formed of a flexible, polymeric material which allows a desired degree of stretching to cause plugging of a borehole. The "plug" formed by an inflatable device of the invention allows loading of explosives into a borehole in order to produce desired blast results according to the several methods of the invention.

Abstract: A rock breaking method includes drilling a hole in rock, filling the hole with water, inserting a short barrel of a rock breaking tool into the hole entrance, covering the tool with a recoil restraining mat, and discharging a cartridge down the barrel.

Abstract: A shaped charge has a case, a cap, and an O-ring. The case has first and second ends and a cavity therein. The case first end has a cylindrical first surface that circumferentially surrounds the cavity. The case second end has a bifurcated projection for receiving a portion of detonating cord. The cap also has first and second ends and cavity therein. The cap first end has a cylindrical second surface that circumferentially surrounds the cap cavity. The case and cap first ends matingly receive each other such that the first and second surfaces face each other. The first and second surfaces have respective circumferential grooves that are aligned with each other when the case and cap are assembled together. The grooves receive the O-ring, which retains the case and cap together while permitting the case to rotate relative to the cap. The cap second end is adapted to couple to a shaped charge carrier.

Abstract: Improved apparatus for perforating a subterranean formation penetrated by a well bore comprised of at least one encapsulated shaped charge held in the well bore adjacent the formation by a charge carrier optionally selected from a wire carrier or a metal strip carrier. The encapsulated shaped charge includes an ignition end and a capped discharge end, the ignition end having an extension providing cavities for containing opposed portions of a pair of wires. The capped discharge end includes a threaded extension whereby the encapsulated shaped charge can optionally be threadedly attached to a complementary threaded opening in a metal strip carrier. A wire carrier adapter nut is threadedly attached to the capped discharge end extension which provides cavities for containing opposed portions of a pair of additional wires of a four-wire carrier.

Abstract: The method of breaking rock by blasting comprises drilling of boreholes, loading of a blasting charge with a means of initiation therein and stemming. The stemming is made up of a phlegmatized low-velocity explosive.

Abstract: A metal tube is expanded by means of an explosive charge into engagement with a surrounding tubular metal member which is supported externally by a surrounding metal die member spaced from the metal member, the intervening space being filled with a shock transmitting liquid such as water. The metal die member is readily separated from the expanded tube and is reusable indefinitely without maintenance. Its use is therefore more economical than the split die hitherto used. The method is especially useful for expanding large diameter tubes, for example expanding oil-well drill pipes into pipe coupling members.

Abstract: There is disclosed an easy to assembly detonating cord retainer arrangement for shaped charges. A portion of a length of detonating cord is laid into the slot of a bifurcated cylindrical projection located at one end of the shaped charge case. A push nut is pressed onto the projection to retain the detonating cord within the slot.

Abstract: A method is provided for loading upwardly extending boreholes in rock with flowable bulk explosives. An explosives loading pipe, an air exhaust pipe and an initiating booster charge with associated initiator are located in the borehole so that the booster and the pipe ends are located deep within the borehole. The ends of the pipes and the initiator are pressed through one or more channels in a cylindrical plug wedged in the borehole opening. Stemming material is first placed in the borehole through the loading pipe to lie against the plug and thereafter the bulk explosive is introduced to fill the borehole. Entrapped air is exhausted through the exhaust pipe.

Abstract: A blast focusing technique for producing high pressure on a ground plane, in which a right circular cylinder of explosive material is positioned adjacent the ground plane with the cylinder axis orthogonal to the ground plane. The cylinder is simultaneously detonated at both ends by detonators disposed on the cylinder axis at each end of the cylinder.

Abstract: An inflatable wand for positioning within an upward oriented, mining borehole and near a lower collar opening thereof wherein the wand provides a conduit for introducing and retaining liquid explosive materials within the borehole. The wand includes a flexible tube with longitudinally oriented reinforcing fibers embedded in an elastic composition such as rubber. The tube is constructed to permit radial elongation in response to a force arising within the tube and directed radially outward, but to restrain against axial elongation during use. Such radial elongation arises because of back pressure developed by the flowing explosive as it is impeded at a valve outlet at the distal end of the wand. Enlargement of the wand seals the opening of the borehole without destruction of the elastic material on sharp points and edges of the borehole collar.

Abstract: An expansive demolition agent prepared by crushing a clinker for manufacturing powdered expansive demolition agent obtained by sintering, which is capable of hydrating and expanding in a hole drilled in a brittle material to demolish the brittle material, the maximum particle diameter of the agent being one-third or less the diameter of the hole, and containing 10% or less of fine particles having a particle diameter of 0.3 mm or less.

Abstract: A shaped charge carrier assembly includes a thin wall carrier having a charge opening disposed therethrough for freely receiving a shaped charge therein. A deformable retaining device is integrally formed with the thin wall carrier adjacent a periphery of the charge opening. The deformable retaining device allows the shaped charge to initially be freely received in the charge opening, but subsequently retains the shaped charge in the charge opening upon deformation of the deformable retaining device.

Abstract: A high energy gas fracturing tool for radially fracturing a rock formation in a well bore consisting of a cylindrical canister that is holed to pass gas and is for housing a stack of propellant modules that are selected to provide a desired burn rate when ignited. Each propellant module mating face is angled from the horizontal between forty-five (45) to seventy-five (75) degrees, and the modules are bonded together with an epoxy resin wherein propellant or explosive particles are mixed, the resin to exhibit burn characteristics similar to those of the propellant stack. The tool, additional to the propellant containing canister, an ignitor rod and explosive device for igniting the propellant stack, mounts a bull head end over a lower end and a reverse thruster assembly that is connected to the canister upper end.

Abstract: The invention relates to an apparatus for explosively severing tubular members at a pre-designated severance level. The apparatus is designed to deliver a detonation signal to a ring-shaped explosive charge, to an annularly formed detonation signal receiving locations, so that explosion takes place substantially simultaneously about the circumference of the explosive charge about internal periphery of the tubular member at the severance level.

Abstract: A method of detonating explosive charges for the breaking of rock and ore comprises the use of two sets of components, one set within the explosive charge and the other set at the surface of the explosive. The set within the exposive comprises a detonator, a first delay element and a passive energy storage device such as a capacitor. The second set which is able to communicate with the first comprises a power source, a second delay element and a means for receiving signals from a remote command source. In a preferred embodiment, the first delay element has a fixed delay and the second delay element has a programmable delay.The method permits of versatility and precision in the use of explosives, using relatively inexpensive components.

Abstract: A method for the electrical sequential initiation of explosions in which a series of detonators (D1-D11) is located in association with a series of explosive charges spaced from one another and in which a shot initiator 12 is used sequentially to initiate firing of the detonators at selected intervals to detonate the explosive charges, characterized in that each detonator is fired without the provision of a delay between the initiation of firing of the detonator at the shot initiator and the actual commencement of firing of the detonator, further characterized in that the interval between the firing of successive detonators is selected from a range of 5 ms to 40 ms.

Abstract: Well stimulation involving use of a liquid explosive composition in the explosive fracturing of subterranean formations such as oil and gas bearing formations. An explosive formulation comprising a nitrate ester explosive component and a phlegmatizer component is introduced into a well penetrating the formation to be fractured. The phlegmatizer component is an alkyl or alkoxy diester which is mixable with the nitrate ester and can be varied in concentration to control the detonation velocity and maximum explosive pressure. Examples of phlegmatizing agents include alkyl or alkoxy alkyl esters of adipate or azelaic acids such as dibutoxyethyl adipate or diisobutyl azelate or polyethylene glycoxy-based diesters such as triethylene glycol dipelargonate. After the formulation is detonated to fracture the formation, the well is placed on production to recover hydrocarbons at an increased rate.

Abstract: For use in a perforating gun assembly, a perforating gun detonator is disclosed. One embodiment is hermetically sealed while the other has openings therein to admit well fluids. In both embodiments, a narrow conductive metal foil is provided with a current to vaporize the narrow foil, explode the foil and propel a flyer driven by a shock wave for detonation of a spaced secondary explosive. The explosive then couples explosion into a detonating cord against a shoulder in a housing adjacent to the secondary explosive. The current is formed by means of an AC voltage multiplier circuit providing a charge on a capacitor which is discharged through a spark gap. Charging circuitry includes a blocking capacitor to prevent DC and a resistor for bleeding a small current from the capacitor to ground which prevents static or stray current accumulation.

Abstract: A nonelectric blasting system, method and device is disclosed for use in establishing a time sequential firing of blasting elements, the device comprised of an elongated tube which contains a low velocity deflagration mixture adhered to the inner walls of said tube. The device, by itself, controls a desired initiation pattern of a plurality of blasting elements by transmitting an initiation signal at a much reduced velocity than conventional shock tube or explosive cord by use of preselected material mixtures.

Abstract: An improved process for the manufacture of water resistant dry blasting agents. Powdered, solid, water blocking agent and solid fuel, if required, is added as a suspension in a liquid non-hydrating fuel phase to porous ammonium nitrate prills. The process thus avoids unevenness of coating with water blocking agent of prior art processes and is particularly suited to on-site truck mounted manufacturing of water resistant blasting agents.

Abstract: A stemming construction for a blast hole loaded with an explosive charge, comprising a tapering wedge member dispersed in the blast hole outwardly of the explosive charge with its narrower end facing outwardly toward the mouth of the blast hole, and particulate stemming material in the blast hole outwardly of the wedge member. Detonation of the explosive drives the wedge member into the stemming material to wedge the stemming material against the walls of the blast hole. The wedge member is preferably cone-shaped and can be provided with a stabilizing rod to prevent it from tilting.

Abstract: A shaped charge carrier assembly is provided for use in a perforating gun of the type used to perforate oil or gas wells. The assembly includes at least one shaped charge including an outer case having an outer surface and a first shoulder extending radially outward from the outer surface. The assembly also includes a carrier having an opening therethrough large enough to receive the outer surface of the case, and having a resilient tab extending into the opening for frictionally engaging at least a first portion of the outer surface of the case, and for thereby holding the shaped charge in place relative to the carrier with the shoulder of the shaped charge abutting the carrier.

Abstract: An improved explosive composition and a method for making the composition are disclosed. The explosive composition is prepared by first formulating a gel concentrate that comprises a mixture of a sensitizer, such as hexamethylenetetramine or hexamethylenetetraminemononitrate and an oxidizer, such as ammonium nitrate in water and a gelling agent. Mixtures of sensitizers or mixtures of oxidizers can also be used in our invention. This gelled concentrate can be prepared, stored and later utilized to form the explosive composition by combining from 5 to 60 parts by weight of the gelled concentrate with from 95 to 40 parts by weight of a particulate oxidizer, such as ammonium nitrate or an ammonium nitrate-fuel oil composition. The resulting explosive compositions have increased densities and hence a significantly higher energy per unit volume.

Abstract: Disclosed herein is a sidewall core gun attached to the lower end of a drill string, enabling the taking of core samples from within a deviated borehole. The gun also includes an improved charge assembly, including a detonatable core and one or more deflagratable cartridge assemblies for propelling a coring bullet from the gun to the sidewall of the borehole. Coring bullets imbedded in the sidewall remain connected to the gun via steel cables, whereby the bullets may be retrieved by raising the drill string.

Abstract: A system for transferring bulk explosive materials comprises at least one bulk explosive material storage tank and a transfer hose connected to this tank. The hose is used to fill a receptacle, typically a borehole in a mine, with explosive material, at least in part. A detonation arrestor device comprises a central channel in the hose adapted to have the explosive materials pass along its outside and fumes to pass along its inside in the event of an unintentional explosion.

Abstract: A method and apparatus for making an in situ disposable propellant canister for utilization in controlled pulse fracturing. Said canister is composed of a porous light fabric material in combination with a gel solution. The gel creates a formable mass after solidification. Said mass can be made of a gel thickness sufficient to support and contain a propellant. Upon ignition of said propellant, the gelled canister is destroyed thereby alleviating a clean up operation.

Abstract: A method of smooth wall rock blasting is provided in which an alignment of boreholes for explosive charging is drilled into rock and a single, smaller diameter empty borehole is drilled close and parallel to, and on each side of each charged borehole. Upon detonation of the charged boreholes, the rock is cracked smoothly along the plane coincident with the axes of the holes. The method reduces drilling costs to a minimum and provides improved results over the previous pre-shearing and other known methods.

Abstract: A shaped charge carrier assembly includes a strip type carrier having openings therein for receiving shaped charges. Each of the openings includes first and second diagonally opposed pairs of resilient tabs for snugly engaging an outer case of the shaped charge. In a preferred embodiment, every second one of the openings includes first and second elongated cord receiving slots communicated therewith, so that the assembly can be put together without threading a free end of a firing cord through openings in the carrier. Integral intermediate portions of the firing cord can be placed through the alternate openings in the elongated cord receiving slots associated therewith without threading the free ends of the firing cord therethrough.

Abstract: A technique for fragmenting rock or other relatively hard and/or compact material without the use of explosives is disclosed herein. In accordance with this technique, an elongated, blind opening is provided in the rock or other material to be fragmented and a pulse of water having a relatively high peak pressure and a relatively rapid rise time is directed into the elongated opening without the use of explosives to produce the pulse, whereby to produce a shock wave in the rock or other material sufficient to fragment it. In an actual embodiment, this explosion free pulse of water has a peak pressure of about 80,000 psi and a rise time of about one millisecond.

Abstract: A device for parting or cutting a tube by means of an explosive charge, comprising a pack of explosive annular pellets 20 and a fuse assembly. The fuse assembly comprises two mutually equal lengths of detonating fuse 10 and 11 of which one 10 extends axially through the said pack 20 and the other 11 is disposed at one end of the said pack 20. Fuse 10 extends between a first booster 17 adjacent to but not contiguous with said one end of the pack 20 and a second booster 18 at the other end of the pack 20, and fuse 11 extends between said first booster 17 and a third booster 19 at said one end of the pack 20. In this way the pack 20 is sandwiched between said second and third booster and simultaneous detonation of the pack 20 at its opposite ends is achieved, when required in use, by application of a single initiation system to the first booster 17.

Abstract: Methods and apparatus are provided for detonating high explosive devices downhole in a well. A high explosive device includes a detonating cord having a first end and a second end. A first device is provided for initiating a detonation of a detonating cord at its first end and a second device is provided for initiating a detonation of the detonating cord at its second end.

Abstract: The invention relates to methods for refining, pumping and loading a borehole with a water-in-oil emulsion slurry blasting composition, wherein the emulsion slurry blasting composition is pumped or forced through a valve positioned at the end of a delivery hose in order to increase the viscosity of the composition prior to its expulsion from the hose.

Abstract: Method and apparatus for making aqueous slurry explosives are disclosed. The components of the aqueous slurry explosive are mixed in a variable speed rotary mixer where the speed of the mixer is determined by the sequence of addition of the explosive components. The explosive components generally comprise water; an inorganic oxidizing salt such as ammonium nitrate; organic liquid such as propylene glycol; organic solids such as sugar; air entraining agents such as microspheres; densifying agents such as hot ammonium nitrate solutions; thickening agents such as flours and guar gums and pH adjustors and self-explosives. The aqueous slurry explosive may be formed using ambient temperature water. The apparatus is particularly suited as a mobile unit for use in the field.

Abstract: A device for actuating an explosive charge downhole in a wellbore. The device includes a combustive reaction initiator actuated in response to a first pressure condition in a portion of the wellbore and an explosive charge actuator. A time delay device is provided wherein a combustive reaction is initiated by the initiator and continues for a time delay period providing sufficient time for an operator to alter the first pressure condition to a second pressure condition desired at the time of explosive actuation. The delay device is operative at the end of the time delay period after initiation to actuate the explosive charge.

Abstract: A charging apparatus includes a charging hose, one end part of which is arranged to be connected to at least one supply of particulate or liquid explosive, and the other end part of which is arranged to be inserted into a drill hole to deliver thereto explosive fed through the charging hose from the forementioned supply; a guide sleeve for guiding the charging hose; a hose-feeder arrangement for displacing the charging hose longitudinally in the guide sleeve; and an aligning and adjusting means for carrying the guide sleeve and placing the aforementioned one end of the sleeve in a position for guiding the other end part of the charging hose into the drill hole. The wall of the guide sleeve is provided with a closeable opening arranged to enable bodies of solid explosive or cartridged explosive to be introduced into the guide sleeve when the charging hose is at least partially withdrawn out of the guide sleeve.