StemPlug's Wedging Action Blocks Stemming Ejection

This photo clearly illustrates the wedging action of the StemPlug. Upon detonation, the explosive gasses seek the path of least resistance and begin to eject the stemming. As the plug begins to move up the borehole, it's conical shape parts the stemming material and jambs some between the plug and the borehole wall.. After movement of approximately 2 borehole diameters upward, the plug will wedge in place and stemming ejection ceases.

The blast energy is retained in the hole, yielding greatly improved fragmentation, while reducing fly rock, air blast, and dust.