Blast plug and stemming construction for blast holes

A stemming construction for a blast hole having an explosive charge therein, said blast hole having side walls, an outwardly opening mouth and a central axis extending longitudinally of the blast hole, said stemming construction comprising:

• a wedge member in the blast hole tapering in an outward direction from a relatively wide base to a relatively narrow end and having a central axis extending endwise with respect to the wedge member, said wedge member being positioned with its base facing inwardly toward the explosive charge, with its narrow end facing outwardly toward the mouth of the blast hole, and with its central axis generally coincident with the central longitudinal axis of the blast hole;
• a stabilizing structure on the wedge member spaced laterally from and surrounding the narrow end of the wedge member in close proximity to the side walls of the blast hole, said stabilizing structure being engageable with the side walls of the blast hole for resisting forces tending to tilt the wedge member away from a position in which the central axis of the wedge member is generally coincident with the central longitudinal axis of the blast hole;
• and
• particulate stemming material in the blast hole disposed outwardly of the wedge member so that upon detonation of the explosive charge the wedge member is adapted to be driven into the stemming material to force the stemming material laterally outwardly toward the side walls of the blast hole.

A plug adapted for use in stemming a blast hole having an explosive charge therein, said blast hole having side walls, an outwardly opening mouth and a central axis extending longitudinally of the blast hole, said plug comprising a wedge member and a stabilizing structure on the wedge member, said wedge member tapering in an outward direction from a relatively wide base to a relatively narrow end and having a central axis extending endwise with respect to the wedge member, said stabilizing structure extending generally axially with respect tot he wedge member from adjacent the base of the wedge member, said plug being adapted to be positioned in said 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, said stabilizing structure being engageable with the side walls of the blast hole for resisting forces tending to tilt the wedge member away from a position in which the central axis of the wedge member is generally coincident with the central longitudinal axis of the blast hole, the wedge member being sufficiently impact-resistant that upon detonation of the explosive charge the wedge member is adapted to be driven outwardly into particulate stemming material disposed within the blast hole outwardly of the wedge member to force the stemming material laterally toward the side walls of the blast hole.

A plug adapted for use in stemming a blast hole having an explosive charge therein, said blast hole having side walls, an outwardly opening mouth and a central axis extending longitudinally of the blast hole, said plug comprising a generally solid wedge member and a stabilizing structure on the wedge member, said wedge member tapering in an outward direction form a relatively wide base t a relatively narrow end and having a central axis extending endwise with respect to the wedge member, said stabilizing structure being spaced laterally from and surrounding the narrow end of the wedge member, said plug being adapted to be positioned in said 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, said stabilizing structure being engageable with the side walls of the blast hole for resisting forces tending to tilt the wedge member away from a position in which the central axis of the wedge member is generally coincident with the central longitudinal axis of the blast hole, the wedge member being sufficiently impact-resistant that upon detonation of the explosive charge the wedge member is adapted to be driven outwardly into particulate stemming material disposed within the blast hole outwardly of the wedge member to force the stemming material laterally toward the side walls of the blast hole.