Lesson 2/Practice Exercise Answers
If available water supplies are limited (or if environmental impact
is important) a recirculating water system should be constructed using
two ponds. One serves as a reservoir for clean water and one as a
settlement pond where dirt, fines, and organic materials can be removed
from the used wash water before it is allowed to return to the reservoir
You should install a grizzly to pre-screen the material and remove
oversize rock. (It is preferable to install the grizzly in the quarry, but
it can also be built over the plant's apron feeder.)
Remove enough overburden to ascertain the structure and
configuration of the underlying rock. All overburden need not be
removed at once. Overburden removal should keep pace on a day-to-
day basis once excavation begins.
Normally, it is easier to maintain a vertical face when rock layers slope
away from the quarry face than it is if they slope toward the face.
This is because rockslides are more likely where fractures or rock
layers slope toward the excavation.