Lesson 2/Learning Event 2
Overburden
The location of overburden disposal is a primary consideration when planning overburden removal.
This location is called a spoil area. Overburden should be disposed of in a place where it will not have
to be handled a second time. It should be clear of all areas planned for future use. Normally,
overburden will be piled to the right and/or left of the longitudinal axis of the quarry. On hillside sites, it
will be piled on the downhill side, outside the pit area. For safety reasons, overburden should never be
piled within 50 feet (16 meters) of the quarry rim. In planning overburden disposal, consider the
relationship of spoil areas to drainage plans and the possibility of using the overburden as construction
fill.
Haul and Access Roads
Roads to the rim of the quarry will follow the shortest and easiest route practicable. Grades will be
limited to a maximum of 10 percent for truck operation. Curves should have sufficient radius to cause
minimum delay in hauling. As a guide, roads should be designed for safe negotiation at not less than 20
miles per hour (32 kilometers per hour) by a loaded dump truck. Two-way roads to and from
operational areas are usually adequate. However, one-way loop roads are essential within operational
areas so that the routes of loaded and empty trucks do not cross. A straight ramp, spiral ramp, or
switchbacks will be needed to maintain acceptable access from the boundary of the pit to the working
face.
Precipitation and ground water seepage must be kept drained away from the quarry face and other areas.
The working floor of the quarry should slope away from the face to prevent water accumulation in the
blasted rock and loading areas. A three percent slope is adequate. In a hillside quarry, water may be
drained off naturally by gravity flow. In subsurface operation it will be necessary to provide a collection
point where water can be accumulated for pumping. These collection points are called sumps. Sumps
should be located away from traffic areas or any other area where they would interfere with efficient
operation.
Equipment Positioning
skids. If necessary, these air compressors can be moved around with the drills they support. However,
for deliberate operations of long duration, it is more desirable to permanently station the compressors.
Rock Crushers. The rock crushing, screening, and washing plant should be located close to the quarry
face, but not close enough to be endangered by
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