Abstract: A method of breaking rock (18), e.g. in underground mining, includes drilling a hole in the rock mass by means of a drilling machine (20) having an articulated boom (22) and a drilling tool (24) at the end of the boom (22). After drilling, the drilling tool (20) is retracted, charge means is indexed with the hole, and a rock breaking charge (30) is charged into the hole. The charge (30) includes a propellant, a fuse head (40), and a tamping medium (34), conveniently contained in the casing (32). The tamping medium (34), e.g. a two-component resin, is discharged into the hole and allowed to set around and rearward of the propellant. The driving machine (20) is removed and the propellant is actuated from a remote position, e.g. electrically.

Abstract: An impulse generating tool for breaking up rock has a barrel, a breech body for a cartridge (50) loaded with gas producing propellant (70) and a firing mechanism for firing the cartridge. A hole is drilled in the rock and filled with water. The barrel is passed down the hole and the cartridge is fired. Shockwaves break up the rock. A firing pin (42) of the firing mechanism is off-set (56) from a centerline (54) of the breech body, and the cartridge, which is of a shotgun type, has a rim-fire percussion cap (63) complemental to the off-set of the firing pin. Conventional shotgun ammunition cannot be fired with the tool, and cartridges for the tool cannot be fired by a conventional shotgun.

Abstract: An impulse generating tool for breaking up rock has a barrel, a breech body for a cartridge (50) loaded with gas producing propellant (70) and a firing mechanism for firing the cartridge. A hole is drilled in the rock and filled with water. The barrel is passed down the hole and the cartridge is fired. Shockwaves break up the rock. A firing pin (42) of the firing mechanism is off-set (56) from a centreline (54) of the breech body, and the cartridge, which is of a shotgun type, has a rim-fire percussion cap (63) complemental to the off-set of the firing pin. Conventional shotgun ammunition cannot be fired with the tool, and cartridges for the tool cannot be fired by a conventional shotgun.