Page 426 - Moving the Earth_ The Workbook of Excavation
P. 426
BLASTING AND TUNNELING
9.26 THE WORK
FIGURE 9.19 Priming small dynamite stick.
FIGURE 9.20 Primacord and a large dynamite stick. (Courtesy of Ensign-Bickford Co.)
placing and tamping the charge. Use of one stick above the primed one cushions the primer
against jars from overzealous tamping, and from contact with abrasive stemming material.
If the hole is long, or the charge heavy, it may be considered a good precaution to use two or
more primers. The second one is liable to be in the bottom, and any additional ones are spaced
throughout the column.
With all types of delay firing the primer must be in or near the bottom. This largely avoids the
danger of throwing the primer out in the muck pile, where it would be likely to detonate during
digging, with a possibility of disastrous results.
