| 摘要 |
A stemming plug constructed from a durable, resilient material and comprising a circumferential wall defining an inner cavity, an end wall at the first end and an open second end. In the preferred embodiment, the circumferential wall is fluted so that it can easily compress and seat in a borehole while maintaining a snug friction fit. The plug is inserted in the borehole over the explosive charge. Stemming material, preferably rock, is placed on top of the plug. The stemming material covers the top and slides down around the circumferential wall and is lodged between the circumferential wall and the borehole. Upon explosion, the blast energy is forced into the inner cavity causing the circumferential wall to expand outwardly and thereby engaging the stemming material and the borehole wall to secure the plug in place. The stemming material can also be placed inside the plug, with blast energy inverting the plug end wall to wedge stemming material within the borehole. |
