| 摘要 |
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. |
