Page 505 - Moving the Earth_ The Workbook of Excavation

PIT OPERATION

PIT OPERATION 10.11

FIGURE 10.11 Piling spoil.

If the machine can be reeved so as to have a live boom, grading off spoil heaps may be made
much easier as the reach can be varied by raising or lowering the boom.
Another system is to cut rough haul roads through the troughs, and build them up with spoil
hauled from fresh stripping. Scrapers usually do this more economically than trucks as they can
spread as well as dump. The troughs may be entirely filled, or just brought up far enough to enable
dozers or other machines to take down the tops.

HAUL-AWAY STRIPPING

When sidecasting does not provide a wide enough work area for removal of a pay formation, or
there is no place for sidecast spoil to be piled, the overburden is loaded and hauled to a dump.
Depth of overburden may be a few inches to more than 600 feet, and the area may be only a
few acres or several square miles. In general, the method is adapted to thicker pay deposits and
deeper overburdens than sidecast stripping.
Mines in which stripping is chiefly done by sidecasting are called strip mines, while those
whose overburden is hauled away are called open pits. Most sand and gravel are obtained from