Abstract: A method of calibrating a pressure sensing apparatus for measuring borehole pressure during blasting operations is provided. The method includes: striking a first piezoelectric sensor of a first unmolded pressure sensing apparatus; determining, with an interference circuit, a first peak voltage of the first piezoelectric sensor during the striking thereof; striking a second piezoelectric sensor of a second molded pressure sensing apparatus; determining with the interference circuit, a second peak voltage of the second piezoelectric sensor during the striking thereof; and calculating a piezoelectric constant of the first piezoelectric from at least the first and second peak voltages.

Abstract: Pressure sensors and techniques are presented in which one or more piezoelectric discs are housed in a holder structure with a hole allowing exposure of the piezoelectric disc(s) to ambient pressure within a borehole, with wiring leads passing through the holder structure for conveying an electrical signal from the piezoelectric device to an external interface circuit or for conveying an electrical signal from an internal interface circuit to an external data acquisition system.

Abstract: A shock tube connector system comprises a substantially cylindrical detonator having a longitudinal axis a block body receiving the detonator therein, and an end cap. The detonator includes an axisymmetric exterior shell including a cylindrical main section, a cylindrical explosive end portion having a diameter less than the diameter of the main section, and a transition portion connecting the main section and the explosive end portion of the shell. An explosive charge is contained within the explosive end portion of the shell and is distributed along the longitudinal length of the explosive end portion. The explosive charge preferable comprises two portions of lead azide or a first charge portion of lead azide and PETN and a second charge portion of PETN. An initiating shock tube is operatively connected to the explosive charge via a delay element. The block body includes a housing within which the main section of the detonator is received.

Abstract: A shock tube connector system comprises a substantially cylindrical detonator having a longitudinal axis a block body receiving the detonator therein, and an end cap. The detonator includes an axisymmetric exterior shell including a cylindrical main section, a cylindrical explosive end portion having a diameter less than the diameter of the main section, and a transition portion connecting the main section and the explosive end portion of the shell. An explosive charge is contained within the explosive end portion of the shell and is distributed along the longitudinal length of the explosive end portion. The explosive charge preferable comprises two portions of lead azide or a first charge portion of lead azide and PETN and a second charge portion of PETN. An initiating shock tube is operatively connected to the explosive charge via a delay element. The block body includes a housing within which the main section of the detonator is received.

Abstract: A shock tube connector system comprises a substantially cylindrical detonator having a longitudinal axis a block body receiving the detonator therein, and an end cap. The detonator includes an axisymmetric exterior shell including a cylindrical main section, a cylindrical explosive end portion having a diameter less than the diameter of the main section, and a transition portion connecting the main section and the explosive end portion of the shell. An explosive charge is contained within the explosive end portion of the shell and is distributed along the longitudinal length of the explosive end portion. The explosive charge preferable comprises two portions of lead azide or a first charge portion of lead azide and PETN and a second charge portion of PETN. An initiating shock tube is operatively connected to the explosive charge via a delay element. The block body includes a housing within which the main section of the detonator is received.

Abstract: A shock tube connector system comprises a substantially cylindrical detonator having a longitudinal axis a block body receiving the detonator therein, and an end cap. The detonator includes an axisymmetric exterior shell including a cylindrical main section, a cylindrical explosive end portion having a diameter less than the diameter of the main section, and a transition portion connecting the main section and the explosive end portion of the shell. An explosive charge is contained within the explosive end portion of the shell and is distributed along the longitudinal length of the explosive end portion. The explosive charge preferable comprises two portions of lead azide or a first charge portion of lead azide and PETN and a second charge portion of PETN. An initiating shock tube is operatively connected to the explosive charge via a delay element. The block body includes a housing within which the main section of the detonator is received.

Abstract: Detonator packaging comprising a casing, a carton for retaining a plurality of casings and spacers for separating and organizing the casing within the carton is disclosed. The casing is formed from a plurality of connected sections of relatively dense material, such as Homeosote. The casing preferably includes two end sections and one or more interior sections retained, or sandwiched, between the two end sections. An opening, or bore, extends through one of the end sections and into one or more of the interior sections. A detonator having an explosive end is inserted into the opening so that the explosive end is retained at least partially within one of the interior sections. A carton is preferably formed of corrugated cardboard and is large enough to hold a plurality, preferably about one hundred fifty, of the casings. Paper or cardboard spacers are used to space the casings from transmission tubes retained within the carton.

Abstract: Detonator packaging comprising a casing, a carton for retaining a plurality of casings and spacers for separating and organizing the casing within the carton is disclosed. The casing is formed from a plurality of connected sections of relatively dense material, such as Homeosote. The casing preferably includes two end sections and one or more interior sections retained, or sandwiched, between the two end sections. An opening, or bore, extends through one of the end sections and into one or more of the interior sections. A detonator having an explosive end is inserted into the opening so that the explosive end is retained at least partially within one of the interior sections. A carton is preferably formed of corrugated cardboard and is large enough to hold a plurality, preferably about one hundred fifty, of the casings. Paper or cardboard spacers are used to space the casings from transmission tubes retained within the carton.

Abstract: A delay primer unit for detonating an explosive material in a borehole with a detonating cord down line extending into the borehole wherein the unit comprises an explosive element capable of detonating the explosive material upon being detonated, means for preventing direct detonation of the explosive element by the down line and an elongated, flexible time delay detonation element having a first end slidably connected to the down line and a second end connected in detonation relationship with the explosive element and generally movable with respect to the first end. The delay element is used to mount the explosive element on the down line.

Abstract: An improved delay primer unit for detonating an explosive material in a borehole with a detonating cord down line extending into the borehole. The primer comprises an explosive element capable of detonating the explosive material upon being detonated, means for preventing direct detonation of the explosive element by the down line, a time delay detonating element extending between the down line and the explosive element with a known detonation time delay value between first and second ends of the delay element, means slidably associating the first end with the down line and means for connecting the second end in detonation relationship with the explosive element. The improvement in this type of unit is the provision of the explosive element as a support element and a detonating cord wrapped around the support element to form a primer.

Abstract: A method of charging a borehole with at least first and second separate sections of explosive material, which method comprises the steps of providing a detonating cord extending into the borehole, providing a first primer on a first carrier having a time delay connection between the cord and the first primer, this time delay having a first selected value, providing a second primer on a second carrier having a time delay connection between a cord and the second primer, the time delay of the second carrier having a second selected value different from the first selected value, sliding the first carrier and primer along the cord and into detonation association with the first section of explosive material and sliding the second carrier and primer along the same cord to detonation association with the second section of explosive material.

Abstract: A method of charging a borehole with at least first and second separate sections of explosive material, which method comprises the steps of providing a detonating cord extending into the borehole, providing a first primer on a first carrier having a time delay connection between the cord and the first primer, this time delay having a first selected value, providing a second primer on a second carrier having a time delay connection between a cord and the second primer, the time delay of the second carrier having a second selected value different from the first selected value, sliding the first carrier and primer along the cord and into detonation association with the first section of explosive material and sliding the second carrier and primer along the same cord to detonation association with the second section of explosive material.

Abstract: A method of packaging an extrudable explosive composition which includes extruding the explosive composition into an extrusion having a desired cross-sectional shape and size and shrinking a heat shrinkable plastic tube constructed around the extrusion to maintain the extruded cross-sectional shape and size of the extruded composition.

Abstract: There is provided an elongated, flexible unitary detonating device of indeterminate length for detonating a selected explosive material within a bore hole. The detonating device includes, in combination, a detonating cord capable of detonating the selected explosive material when initiated while in direct contact with the selected explosive and a flexible energy absorbing layer formed around and carried by the detonating cord. The energy absorbing layer is formed from an energy absorbent material and has a radial thickness sufficient to preclude detonation of the selected explosive in direct contact with the energy absorbing layer when the detonating cord is initiated. In addition, an arrangement is provided for allowing stripping of the energy absorbing layer from the detonating cord at any selected position along the detonating cord to expose a portion of the detonating cord.

Abstract: There is provided an elongated, flexible unitary detonating device of indeterminate length for detonating a selected explosive material within a bore hole. The detonating device includes, in combination, a detonating cord capable of detonating the selected explosive material when initiated while in direct contact with the selected explosive and a flexible energy absorbing layer formed around and carried by the detonating cord. The energy absorbing layer is formed from an energy absorbent material and has a radial thickness sufficient to preclude detonation of the selected explosive in direct contact with the energy absorbing layer when the detonating cord is initiated. In addition, an arrangement is provided for allowing stripping of the energy absorbing layer from the detonating cord at any selected position along the detonating cord to expose a portion of the detonating cord.

Abstract: A method of charging a borehole with at least first and second separate sections of explosive material, which method comprises the steps of providing a detonating cord extending into the borehole, providing a first primer on a first carrier having a time delay connection between the cord and the first primer, this time delay having a first selected value, providing a second primer on a second carrier having a time delay connection between a cord and the second primer, the time delay of the second carrier having a second selected value different from the first selected value, sliding the first carrier and primer along the cord and into detonation association with the first section of explosive material and sliding the second carrier and primer along the same cord to detonation association with the second section of explosive material.

Abstract: A method of charging a borehole with at least first and second separate sections of explosive material, which method comprises the steps of providing a detonating cord extending into the borehole, providing a first primer on a first carrier having a time delay connection between the cord and the first primer, this time delay having a first selected value, providing a second primer on a second carrier having a time delay connection between a cord and the second primer, the time delay of the second carrier having a second selected value different from the first selected value, sliding the first carrier and primer along the cord and into detonation association with the first section of explosive material and sliding the second carrier and primer along the same cord to detonation association with the second section of explosive material.