| 摘要 |
<p>A stemming device (10) for use with a charge (44) containing a gas producing material in a borehole (46) is provided. The stemming device (10) has a piston (14) movable from a rest position to an operative position relative to a complementary static member (12) to cause radial expansion of the stemming device (10). The piston (14) has a leading end (36) which operatively faces the charge (44) in the borehole (46) and provides a sliding fit within the borehole (46) and which is configured to move under action from the charge (44) or gas produced by the charge (44). The device (10) is further configured to accommodate an actuating tube or cable (20) extending from the charge (44) externally of the borehole (46) and the static member (12) includes formations (24) to engage the sides of the borehole (46).</p> |
