Page 139 - Moving the Earth_ The Workbook of Excavation

ROCK, SOIL, AND MUD

ROCK, SOIL, AND MUD 3.33

FIGURE 3.24 Loading for ditch blast.

center of the group to be blasted, and with the loads and distances shown in the illustrations,
should detonate them all.
However, if the structure of the muck changes between holes, it may shear, and direct the force
of the concussion upward or to the side, and charges beyond that point will not explode. In this
case, one of the remaining charges should be lifted and primed with a cap, or an additional primed
stick should be placed and detonated.
If many reprimings are necessary, it may be better to put a cap in each hole and explode them
simultaneously by electricity. As a great many caps are generally used in a single blast of this
type, a powerful jolt of electricity is needed.
It is not usually necessary to remove stumps and brush from an area to be ditched by explo-
sives, but trees should be cut and the trunks removed if possible. Extra charges should be placed
under stumps, and an effort should be made to get them to throw toward the nearest edge of the
ditch. If the stumps are so heavy or so numerous that they prevent accurate ditch work, they may
be removed first by draglines, winches, or other machinery, perhaps with some blasting to loosen
them up.