Abstract: An apparatus, method and insulation medium for inserting and insulating a charge medium within a borehole includes a charge tube comprised of an elongate tube having a length and diameter sufficient for containing a desired quantity of a charge medium. A charge medium in a pumpable form is provided for substantially filling the charge tube. An insulation medium in a pumpable form is provided for substantially encapsulating the charge tube and substantially filling an annular space between the charge tube and the borehole for insulating the charge tube from a downhole environment in which the charge tube is to be inserted. A detonator is inserted within the charge medium proximate a distal end of the charge tube and a charge cable extends from the detonator through the charge tube and exits from the charge tube.

Abstract: Methods for evaluating drill pattern parameters such as burden, spacing, borehole diameter, etc., at a blast site are disclosed. One method involves accumulating the burden contributed by successive layers of rock and matching the accumulated rock burden to a target value for a borehole having a length related to the average height of the layers. Another method relates to varying drill pattern parameters and characteristics to match blast design constraints, including the substitution of one explosive material for another by the proper balance of materials and/or output energies to the associated rock burden. Analysis of deviations from target rock burdens and corrective measures are disclosed, as well as cost optimization methods. The various methods can be practiced using an appropriately programmed general purpose computer.

Abstract: An explosive tool is disclosed. The explosive tool comprises a body structure, a charge, a detonator to ignite the charge via propagation of thermal energy, a pressure actuated safety to prevent propagation of sufficient thermal energy to ignite the charge when the pressure actuated safety is subjected to a surface pressure and to not prevent propagation of sufficient thermal energy to ignite the charge when the pressure actuated safety is subjected to at least a predefined pressure threshold, and a temperature actuated safety to prevent propagation of sufficient thermal energy to ignite the charge when the temperature actuated safety is subjected to a surface temperature and to not prevent propagation of sufficient thermal energy to ignite the charge when the temperature actuated safety is subjected to at least a predefined temperature threshold. The charge, the detonator, the pressure actuated safety, and the temperature actuated safety are contained within the body structure.

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: One aspect of the invention concerns a method of charging an upwardly oriented hole with a pumpable material, typically a pumpable explosive material such as an ANE. In the method of the invention a laterally expandable retainer is provided. This is of smaller length than the hole and has an inlet at a lower end thereof and an outlet at an upper end thereof. In an unexpanded state the retainer has a smaller lateral dimension than the hole. The retainer is inserted upwardly into the hole in an unexpanded state, whereafter material with which the hole is to be charged is pumped upwardly into the retainer through the inlet such that the retainer fills up and expands laterally into engagement with a wall of the hole. Excess pumped material is allowed to upwardly out of the retainer into the hole through the outlet. After the retainer has been filled with material and the hole above the retainer has been at least partially filled with any excess material, the pumping operation is stopped and the inlet is closed.

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 shaped charge includes a charge case; a liner; an explosive retained between the charge case and the liner; and a primer core disposed in a hole in the charge case and in contact with the explosive, wherein at least one of the case, the liner, the primer core, and the explosive comprising a material soluble in a selected fluid. A perforation system includes a perforation gun, comprising a gun housing that includes a safety valve or a firing valve, wherein the safety valve or the firing valve comprises a material soluble in a selected fluid.

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 perforating gun assembly for use in a wellbore. The perforating gun assembly includes a carrier gun body and a charge holder disposed within the carrier gun body. A plurality of shaped charges are supported within the carrier gun body. A secondary pressure generator is operably associated with at least one of the shaped charges. The secondary pressure generator optimizes the wellbore pressure regime immediately after detonation of the shaped charges by controlling the dynamic underbalance created by the empty gun chambers to prevent excessive dynamic underbalance which may detrimentally effect the perforating operation.

Abstract: The invention relates to a mining vehicle and method for its energy supply. The mining vehicle has a carriage, driving equipment for moving the carriage, and at least one mining work device. Further, the mining vehicle has at least one electric motor for operating a main function of the mining vehicle, and at least one electric motor for operating an auxiliary function of the mining vehicle. The mining vehicle further has a power-generating auxiliary unit. When necessary, the power-generating auxiliary unit supplies at least part of the power required by the electric motor operating the auxiliary function.

Abstract: Some demonstrative embodiments of the invention include a method, device and/or system of deploying a payload. In some demonstrative embodiments, the system may include an invertible sleeve capable of being expanded in an inside-out manner, wherein first and second surfaces of the sleeve, which face outward and inward, respectively, when the sleeve is at an unexpanded state, face inward and outward, respectively, when the sleeve is at an expanded state; a payload conveyer to convey the payload, wherein the payload conveyer is detachably connectable to a first end of the sleeve; and a pressurizer to expand the sleeve by applying a pressure through a second end of the sleeve. Other embodiments are described and claimed.

Abstract: A system (10) for loading a flowable explosive into blast holes includes a mobile explosives supply unit (12) having at least one explosives feed line for feeding a flowable explosive from the supply unit (12) into a blast hole, a global positioning system (GPS) unit (14) operable to determine the position of a blast hole, and a blast hole identification processor (16) in communication with the GPS unit (14) operable to receive from the GPS unit (14) a blast hole co-ordinate position. The processor (16) is configured or programmed uniquely to identify the blast hole based on the co-ordinate position of the blast hole.

Abstract: A system and method is provided for identifying any one or more of a plurality of blast holes in a drill pattern. The method involves providing each blast hole in a drill pattern with an individually identifiable first identifier and a GPS device capable of relaying identification and location data for the respective blast hole. A data reception system is provided to receive the data and store it in a database for processing purposes. The information may be later used to correlate any one or more of the blast holes with a corresponding detonator.

Abstract: A method for detonation of a plug device in a fluid environment is described, which is in contact with a body, such as an ignition pellet, and it is characterized in that a number of pressure increases are exerted against the plug device, whereby each pressure increase causes a movement of a piston (10) which is radially arranged in a casing (12), which causes the casing (12) to move a fixed distance inward in the plug device with each pressure increase, up until the displacement of the casing (12) causes the piston to be displaced into a cavity (38), and the fluid environment enters the plug device via an inlet. Also described is a plug device which is in contact with a body, such as an ignition pellet, where the plug device is arranged to detonate after a number of pressure increases that are exerted against the plug device.

Abstract: An explosives container comprising a flexible inner bag within a flexible outer bag, the outer bag comprising a first end and a second end and a booster compartment located on an external surface of the outer bag, adjacent the second end. An explosive composition can be located within the inner bag and, in use, the booster compartment contains an explosive booster and serves to maintain the explosive booster in close contact with the explosives composition. The explosives container further comprises an elongate sheath extending substantially between the first end and the second end of the outer bag and serving to house and protect a detonator cord from damage or dislodgement.

Abstract: A system and method for conducting a firing sequence including a master device and a plurality of electronic pyrotechnic devices, wherein the master device broadcasts, multiple times, a fire command to the plurality of electronic pyrotechnic devices, the electronic pyrotechnic devices commence a pre-fire countdown in response to each fire command received without error, and each electronic pyrotechnic device conducts a pre-fire countdown to expiration and thereupon commences a final fire countdown that concludes with firing.

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 perforating device has an elongated tubular housing and a loading device supporting a plurality of shaped charges. The loading device and the shaped charges are located inside the housing. A volume reduction device is adapted to fit within the loading device and to conform to the profile of the shaped charges thereby filling open volume in the housing.

Abstract: An explosive tool is disclosed. The explosive tool comprises a body structure, a charge, a detonator to ignite the charge via propagation of thermal energy, a pressure actuated safety to prevent propagation of sufficient thermal energy to ignite the charge when the pressure actuated safety is subjected to a surface pressure and to not prevent propagation of sufficient thermal energy to ignite the charge when the pressure actuated safety is subjected to at least a predefined pressure threshold, and a temperature actuated safety to prevent propagation of sufficient thermal energy to ignite the charge when the temperature actuated safety is subjected to a surface temperature and to not prevent propagation of sufficient thermal energy to ignite the charge when the temperature actuated safety is subjected to at least a predefined temperature threshold. The charge, the detonator, the pressure actuated safety, and the temperature actuated safety are contained within the body structure.

Abstract: A system (10) for loading a flowable explosive into blast holes includes a mobile explosives supply unit (12) having at least one explosives feed line for feeding a flowable explosive from the supply unit (12) into a blast hole, a global positioning system (GPS) unit (14) operable to determine the position of a blast hole, and a blast hole identification processor (16) in communication with the GPS unit (14) operable to receive from the GPS unit (14) a blast hole co-ordinate position. The processor (16) is configured or programmed uniquely to identify the blast hole based on the co-ordinate position of the blast hole.

Abstract: Methods for evaluating drill pattern parameters such as burden, spacing, borehole diameter, etc., at a blast site are disclosed. One method involves accumulating the burden contributed by successive layers of rock and matching the accumulated rock burden to a target value for a borehole having a length related to the average height of the layers. Another method relates to varying drill pattern parameters and characteristics to match blast design constraints, including the substitution of one explosive material for another by the proper balance of materials and/or output energies to the associated rock burden. Analysis of deviations from target rock burdens and corrective measures are disclosed, as well as cost optimization methods. The various methods can be practiced using an appropriately programmed general purpose computer.

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: One aspect of the invention concerns a method of charging an upwardly oriented hole with a pumpable material, typically a pumpable explosive material such as an ANE. In the method of the invention a laterally expandable retainer is provided. This is of smaller length than the hole and has an inlet at a lower end thereof and an outlet at an upper end thereof. In an unexpanded state the retainer has a smaller lateral dimension than the hole. The retainer is inserted upwardly into the hole in an unexpanded state, whereafter material with which the hole is to be charged is pumped upwardly into the retainer through the inlet such that the retainer fills up and expands laterally into engagement with a wall of the hole. Excess pumped material is allowed to upwardly out of the retainer into the hole through the outlet. After the retainer has been filled with material and the hole above the retainer has been at least partially filled with any excess material, the pumping operation is stopped and the inlet is closed.

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: The present invention is directed to a mobile platform for the delivery of bulk explosives to a blast hole. One embodiment of the platform provides a tank for holding an explosive composition and a rotary shaft that supports a mixing blade that mixes the explosive composition within the tank. The platform further comprises bearing structure for supporting the rotary shaft that is located to deter any of the explosive composition from entering the bearing.

Abstract: A borehole liner comprising a continuous length of polymer tubing of alternating diameters forming undulations sized for creating undulations in the liner to optimize the annular air gap alternating with full bore hole diameter loads of explosive to effectively reduce overall explosives consumption by 1-20%. Explosive charge weights can be modified to meet the users needs without introducing inert materials or other more labor intensive alternative.

Abstract: A loading tube for use in a perforating gun is disclosed which eliminates the necessity for utilization of plastic jackets to restrain shaped charges. The loading tube comprises a first tubular member and an engagement structure in the first tubular member in which the primer ends of the shaped charges may be installed. These engagement structures may be a center plate or inner tubular members. In each of the disclosed embodiments, a detonating cord connects the primer ends of the shaped charges which are installed in the loading tube.

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: 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 apparatus that is usable with a well includes a perforating system that is adapted to be fired downhole in the well. The perforating system includes a component, which includes an alloy that has a negative corrosion potential and is unable to passivate, or self-protect, while deployed in the well. The component is adapted to disintegrate to form substantially no debris in response to the firing of the perforating system.

Abstract: A buffering device for use in conjunction with a downhole tool string, wherein the tool string includes a ballistics device. The buffering device includes a mandrel attached within a tool string and proximate to the ballistics device. An anchor is disposed on the mandrel and a disk plate is coaxially placed on the mandrel that is slideable thereon. The disk plate is proximate to the ballistic device. A resilient member, such as a spring, is coaxially placed on the mandrel between the disk plate and the anchor. The pressure wave produced by activation of the ballistic device pushes the disk plate toward the anchor and compresses the spring there between. Since the disk plate extends outward into sealing contact with casing lining the wellbore, compression of the spring dissipates energy waves produced by activation of the ballistic device.

Abstract: An apparatus for controlling a wellbore energy train may include a firing head, a detonator cord associated with the firing head, and a plurality of serially aligned modules. Each module may include an enclosure, a first portion of a high order detonation material positioned at one end of the enclosure, a second portion of the high order detonation material positioned at the other end of the enclosure, and a low order detonation material interposed between the first portion and the second portion. A method for controlling an energy train generated in a wellbore may include serially aligning a plurality of the modules along the path of the energy train, and detonating at least one of the plurality of modules by detonating a detonator cord.

Abstract: An explosive cartridge for generating an explosion in a blast hole, the explosive cartridge comprising a flexible casing for containing an explosive and a mechanism for expanding the casing in a first direction and for simultaneously contracting the casing in a second direction which differs from the first direction.

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 marker for use in a blasting system which includes a harness, the marker including a control unit, a memory in which information is stored and a connector for connection to a selected location on the harness whereby, upon receipt of an enabling signal via the harness, the information is made available by the control unit.

Abstract: An apparatus for use in a wellbore comprises a heat insulating container having an inner space and having a structure defining a hollow containing a vacuum. The apparatus further comprises a reflective layer arranged on a surface of the heat insulating container to reflect heat for reducing radiated heat originated in the wellbore from reaching the inner space. Also, a signal-activated detonator is provided in the inner space of the heat insulating container.

Abstract: A blasting system facilitates the actuation of a plurality of programmable detonators according to a desired blasting pattern, to cause the discharge of a plurality of associated charges, by downloading to the detonators blasting information that can be automatically determined by a portable handheld unit that incorporates a positional detecting device, such as a GPS device. The blasting information for any given detonator can be determined by the handheld unit as a function of the distance and the direction of the movement of the unit to the detonator, and/or by the actual GPS location while at the site of the detonator. This automatic determination of blasting information, and particularly the delay times, based on the movement of the unit to the detonator, eliminates error prone human calculations of the delay times needed for multiple detonators at a blasting site. This simplifies the operations and procedures needed for achieving a desired blasting pattern, without sacrificing safety or quality.

Abstract: The invention provides a conveyance device, suitable for traveling along a surface and conveying an explosive charge, the conveyance device including a propulsion member having two opposite ends, the propulsion member being displaceable between a longitudinally extended position wherein the ends are displaced away from one another; and a longitudinally contracted position wherein the ends are displaced toward one another; an outer gripping member and an inner gripping member, each gripping member being displaceable between a circumferentially expanded position wherein an outer perimeter of the gripping member is displaced away from a center of the member so as to, in use, abut at least part of the surface; and a circumferentially contracted position wherein an outer perimeter of the gripping member is displaced towards the center of the member so as to be spaced apart from the surface; the propulsion member and the gripping members being configured in order for sequential displacement of the propulsion member

Abstract: A perforating apparatus (100) includes a plurality of shaped charges (102) each having an initiation end and a discharge end. A detonating cord (116) is operably coupled to the initiation ends of the shaped charges (102). A carrier (106) contains the shaped charges (102). The carrier (106) includes at least one discharge location corresponding to the discharge ends of the shaped charges (102) when the perforating apparatus (100) is in its operable position. The discharge location has first and second material layers (122, 124) wherein the second material layer (124) exhibits resilient recovery such that an opening created by a jet formed from detonating one of the shaped charges (102) in the second material layer (124) is smaller than an opening created by the jet in the first material layer (122), thereby retaining debris in the perforating apparatus (100) with the second material layer (124).

Abstract: An inflatable air tube includes a sleeve member arranged concentrically about the upper end portion of the air tube to define a receptacle chamber for receiving a quantity of bulk explosive blasting powder, thereby to add weight to the air tube for positioning and stabilizing the same in the bulk explosive powder during the depositing of the powder into a blasting hole drilled into the ground. According to the method of the present invention, a plurality of accurate blasting patterns may be provided in the blasting powder column by timing the manual or mechanical insertion of the air tubes into the bulk blasting powder relative to the rate of supply of the powder from a source thereof.

Abstract: A borehole liner comprising a continuous length of polymer tubing of alternating diameters forming undulations sized for creating undulations in the liner to optimize the annular air gap alternating with full bore hole diameter loads of explosive to effectively reduce overall explosives consumption by 1-20%. Explosive charge weights can be modified to meet the users needs without introducing inert materials or other more labor intensive alternative.

Abstract: A shaped charge includes: a charge case; an explosive disposed inside the charge case; and a liner for retaining the explosive in the charge case, wherein the liner is fabricated from a material soluble with a selected dissolving fluid (e.g., an acid, an acid matrix, an injection fluid, a completion fluid, and/or a wellbore fluid). A method for perforating in a well includes the steps of: disposing a perforating gun in the well, wherein the perforating gun comprises a shaped charge having a charge case, an explosive disposed inside the charge case, and a liner for retaining the explosive in the charge case, wherein the liner is fabricated from a material soluble with a selected dissolving fluid; detonating the shaped charge to form a perforation tunnel in a formation zone; and exposing the material comprising the liner to the selected dissolving fluid.

Abstract: An apparatus for use in a wellbore comprises a heat insulating container having an inner space and having a structure defining a hollow containing a vacuum. The apparatus further comprises a reflective layer arranged on a surface of the heat insulating container to reflect heat for reducing radiated heat originated in the wellbore from reaching the inner space. Also, a signal-activated detonator is provided in the inner space of the heat insulating container.

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: An apparatus for controlling a wellbore energy train may include a firing head, a detonator cord associated with the firing head, and a plurality of serially aligned modules. Each module may include an enclosure, a first portion of a high order detonation material positioned at one end of the enclosure, a second portion of the high order detonation material positioned at the other end of the enclosure, and a low order detonation material interposed between the first portion and the second portion. A method for controlling an energy train generated in a wellbore may include serially aligning a plurality of the modules along the path of the energy train, and detonating at least one of the plurality of modules by detonating a detonator cord.

Abstract: A perforating apparatus (100) includes a plurality of shaped charges (102) each having an initiation end and a discharge end. A detonating cord (116) is operably coupled to the initiation ends of the shaped charges (102). A carrier (106) contains the shaped charges (102). The carrier (106) includes at least one discharge location corresponding to the discharge ends of the shaped charges (102) when the perforating apparatus (100) is in its operable position. The discharge location has first and second material layers (122, 124) wherein the second material layer (124) exhibits resilient recovery such that an opening created by a jet formed from detonating one of the shaped charges (102) in the second material layer (124) is smaller than an opening created by the jet in the first material layer (122), thereby retaining debris in the perforating apparatus (100) with the second material layer (124).

Abstract: This invention discloses an apparatus to mechanically stem (plug) a borehole or blast hole to contain or confine the gases generated by explosives, thus preventing the energy generated by explosives to be released to the atmosphere. An assembly of the mechanical stemming apparatus for mining blasting operations according to the present invention comprises 2 pieces, placed one over the other: a base piece (1) and a central piece (6), and additionally includes two lateral wedge pieces (8) and four supporting pivots (11). The mechanical stemming apparatus according to the present invention and the entire apparatus set form a cylindrical body with a diameter lower than the borehole diameter and a length directly proportional to the diameter and depth of the boreholes or blast holes.

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.