Abstract: A method of stemming a blast hole loaded with an explosive charge. The blast hole has side walls, an outwardly opening mouth and a central axis extending longitudinally of the blast hole. The method comprises inserting a conduit having a discharge end inwardly through the mouth of the blast hole and positioning the discharge end of the conduit within the blast hole generally adjacent the explosive charge. Particulate stemming material is forced under pressure through the conduit for exit from its discharge end into the blast hole toward the explosive charge thereby to pack stemming material in the blast hole adjacent the explosive charge. As stemming material is forced out the discharge end of the conduit, the discharge end of the conduit is moved generally axially outwardly relative to the blast hole toward the mouth of the blast hole to simultaneously fill and pack the blast hole with stemming material.

Abstract: A plug for use in stemming a blast hole having an explosive charge therein. The plug comprises a wedge member and a stabilizing structure on the wedge member. The wedge member tapers in an outward direction from a relatively wide base to a relatively narrow end and has a central axis extending endwise with respect to the wedge member. The stabilizing structure extends generally axially with respect to the wedge member from adjacent the base of the wedge member. The plug is to be positioned in the blast hole with the base of the wedge member facing inwardly toward the explosive charge, with the narrow end of the wedge member facing outwardly toward the mouth of the blast hole, with the central axis of the wedge member generally coincident with the central longitudinal axis of the blast hole, and with the stabilizing structure in close proximity to the side walls of the blast hole.

Abstract: A dual purpose fuze for a projectile which can activate a quantity of material selected from a group including high explosive, low explosive, propellant and pyrotechnic compounds. The fuze includes a charge holder having a socket therein facing the quantity of material to be activated. A fuze charge located in the socket has a depression in it so formed as to cause the fuze charge to explode in a jet directed outwardly from the socket of sufficiently high energy to activate a high explosive in a high explosive projectile, the fuze charge being sufficiently small to prevent rupture of containment for a propellant in a cargo projectile. The fuze further includes mechanisms for arming and detonating the fuze charge as well as for activating detonation. A safety mechanism is provided to prevent premature detonation of the fuze charge.

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 detonation system for use with supply of electrical energy has user operable firing console for selectably transmitting unit identification information, firing delay time information and selections from a command set including Output, Delay, Fire (Time), Abort, Power Up (Arm), Input, and Store. The console displays responses or information digested from responses by electrical delay detonators to the commands. The detonators have explosive, a capacitor for storing energy from the supply to set off the explosive, circuitry for charging the capacitor from the supply and transferring the energy from the capacitor to the explosive in response to first and second signals generated in response to the commands. Each detonator can be programmed with a unique identification number and delay time. The time base in each detonator can be compensated so that errors in the time base are obviated so as to achieve the correct delay.