Page 142 - Moving the Earth_ The Workbook of Excavation
P. 142
ROCK, SOIL, AND MUD
3.36 THE WORK
FIGURE 3.27 Bottom shooting.
The core is placed in the casing, and the two are pushed or hammered down into the mud by
means of the handle. The core is withdrawn, the casing being held down if necessary by a foot posi-
tioned on a bump welded on the side. The charge may then be dropped down in the casing, or
pushed down by a long wood tamping stick of the same diameter as the core. This stick is used to
hold the charge down while the casing is pulled out. Difficulties experienced will increase with the
size and length of the pipe, and it may be necessary to use chain jacks or hoists to pull the casing.
Space permits only this brief summary of mud blasting techniques. Further information may
be obtained in other parts of this volume, and from various books and bulletins dealing with
explosives, but it is advisable to have an experienced mud blaster on any important job.
Results. A fault of all mud removal techniques mentioned is that they require placing a consid-
erable depth of fill in a single layer so that it cannot be properly compacted; or the fill is shaken
