Abstract: A stemming plug (60) for stemming a blast hole in a mine is disclosed. The plug has first and second wedge-shaped members (62?, 62) manufactured from a suitable plastics material. The first wedge-shaped member (62?) has a first sloping face received in sliding relationship with a matching face of the second wedge-shaped member (62) wherein, in use, when the first wedge-shaped member (62?) is positioned nearest to an explosive material in the blast hole it has a larger surface area facing the explosive material than the second wedge-shaped member (62). In use, when a Shockwave from initiation of the explosive material in the blast hole encounters the first wedge-shaped member (62?) it acts as a piston, sliding on the second wedge-shaped member (62) so that both wedge-shaped members exert diametrically opposed forces against the wall of the blast hole to lock the plug (60) in place. The two wedge-shaped members (62?, 62) may be substantially identical, thus significantly simplifying the manufacturing process.

Abstract: A stemming plug (60) for stemming a blast hole in a mine is disclosed. The plug has first and second wedge-shaped members (62?, 62) manufactured from a suitable plastics material. The first wedge-shaped member (62?) has a first sloping face received in sliding relationship with a matching face of the second wedge-shaped member (62) wherein, in use, when the first wedge- shaped member (62?) is positioned nearest to an explosive material in the blast hole it has a larger surface area facing the explosive material than the second wedge-shaped member (62). In use, when a Shockwave from initiation of the explosive material in the blast hole encounters the first wedge-shaped member (62?) it acts as a piston, sliding on the second wedge-shaped member (62) so that both wedge-shaped members exert diametrically opposed forces against the wall of the blast hole to lock the plug (60) in place. The two wedge-shaped members (62?, 62) may be substantially identical, thus significantly simplifying the manufacturing process.

Abstract: A plug (10) for blocking off mining exploration drill holes. The plug (10) comprises an elongate body (12) of solid impervious material, and an engineered surface (14) is provided on an external circumference of the elongate body (12). The engineered surface (14) comprises an annular anchoring groove (16) having a ramp (18) extending from a maximum diameter to a minimum diameter of the engineered surface (14) in a braking direction, in which it is intended to prevent movement of the plug (10) in the drill hole. The plug (10) also comprises an O-ring (20) received in the anchoring groove (16) and having a thickness whereby it protrudes slightly above the maximum diameter of the engineered surface (14) and engages with a wall (22) of the drill hole.

Abstract: A stemming plug (10) for stemming a blast hole in a mine, the plug (10) comprising an active wedge-shaped member (12) having a sloping face received in sliding relationship with a matching face of a passive wedge-shaped member (14). In use, the active wedge-shaped member (12) is positioned nearest to an explosive material in the blast hole and the passive wedge-shaped member (14) is positioned further from the explosive material in the blast hole. The active wedge-shaped member (12) has a friction reducing material provided on at least part of its surface to reduce the sliding resistance of the active wedge-shaped member (12) relative to the passive wedge-shaped member (14); whereby, in use, when a shockwave from initiation of the explosive material in the blast hole encounters the active wedge-shaped member (12) it acts as a piston, sliding on the passive wedge-shaped member (14) so that both wedge-shaped members exert diametrically opposed forces against a wall of the blast hole and are locked in place.

Abstract: A grout plug 10 for plugging a drill hole 20 in a mine. The plug 10 comprises an elongate sleeve 12 of porous material adapted to be received in a drill hole 20 and a volume of dry grout material 14 in particulate form. The plug 10 also comprises a liner 16 of water-soluble material, the liner 16 being provided within the porous sleeve 12 for containing the grout material 14 within the porous sleeve 12 in its dry form. In use, when the plug 10 is exposed to water the liner 16 dissolves and the water mixes with the grout material 14 to form a slurry which can seep through the porous sleeve 12 when the plug 10 is tamped into the drill hole 20 to block the drill hole 20 when the grout material 14 cures. A related clay plug is also described having a central core of substantially solid material of low permeability which forms a substrate against which the clay material may cure.