Abstract: This invention relates to a booster explosive support device 10 for use in boreholes 87. The device 10 includes a securing arrangement 12 which is configured to secure an explosive booster 100 to the device 10, and a spacing element 39 which protrudes from the securing arrangement 12. The spacing element 39 has a free end which in use abuts against a closed end or bottom of a borehole, thereby supporting the securing arrangement 12 and hence an explosive booster 100 at a desired spacing from the bottom of the borehole 87. The spacing element 39 may be elongate. The invention also relates to a method of securing an explosive booster 100 at a pre-determined position in a borehole 87. The method includes spacing the explosive booster 100 away from a closed end of the borehole 87 by supporting the explosive booster 100 from an operatively lower position thereof.

Abstract: This invention relates to a booster explosive support device 10 for use in boreholes 87. The device 10 includes a securing arrangement 12 which is configured to secure an explosive booster 100 to the device 10, and a spacing element 39 which protrudes from the securing arrangement 12. The spacing element 39 has a free end which in use abuts against a closed end or bottom of a borehole, thereby supporting the securing arrangement 12 and hence an explosive booster 100 at a desired spacing from the bottom of the borehole 87. The spacing element 39 may be elongate. The invention also relates to a method of securing an explosive booster 100 at a pre-determined position in a borehole 87. The method includes spacing the explosive booster 100 away from a closed end of the borehole 87 by supporting the explosive booster 100 from an operatively lower position thereof.

Abstract: A drill hole (350) extends into rock to be blasted. A blasting accessory (310) includes a container portion (312) for holding a predetermined volume of stemming material, and a spacer (330) for spacing the stemming material a predetermined distance from a surface, e.g. a blind bottom of the drill hole. The container portion has a top (320) surrounded by a dilatable, inverted skirt forming a seal (342), and forms a support for a blasting substance like an explosive.

Abstract: A blasting arrangement (10) includes drillholes (30) in a rock mass (20). Blind ends (32) are drilled to a desired level and, if necessary, are adjusted as shown at (62) to said level. Each hole (30) is plugged by means of a plug (42), which is protected by non flammable buffer material (44), at a level (40) spaced from the end (32). Explosive (50) is charged above the level (40) and the hole is tamped, shown at (60). The holes are detonated desirably by detonators (52), forcing the plugs (42) downwardly and compressing air in chambers (34) above the ends (32). The weakest part of each hole, around the end (32), is split causing a three dimensional zone of weakness at the level of the ends (32). Air forced into the zone of weakness causes a fracture zone (70) at that level, inhibiting propagation of blasting shock waves and protecting the material underneath the level of the ends (32).

Abstract: A blasting arrangement (10) includes drillholes (30) in a rock mass (20). Blind ends (32) are drilled to a desired level and, if necessary, are adjusted as shown at (62) to said level. Each hole (30) is plugged by means of a plug (42), which is protected by non flammable buffer material (44), at a level (40) spaced from the end (32). Explosive (50) is charged above the level (40) and the hole is tamped, shown at (60). The holes are detonated desirably by detonators (52), forcing the plugs (42) downwardly and compressing air in chambers (34) above the ends (32). The weakest part of each hole, around the end (32), is split causing a three dimensional zone of weakness at the level of the ends (32). Air forced into the zone of weakness causes a fracture zone (70) at that level, inhibiting propagation of blasting shock waves and protecting the material underneath the level of the ends (32).

Abstract: A plug for use in a borehole, the plug including a body member of a flexible material, the body member defining a floor portion, with a wall portion bounding and extending from the floor portion for engagement with an inner wall of the borehole for sealing the borehole. The invention also relates to a method of supporting materials in a borehole.