and the nature of end products required for construction
projects. The four basic setups are as follows:
1. The jaw crusher is used alone to work with
quarry rock. Large quantities of material are ordinarily
needed for base course, roads, and airfields; the fine
particles are desired for binder. This means all of the
crushed material is used together with no screening
2. The primary and secondary units are used in
conjunction with each other to produce graded
aggregate from quarry rock. The material is reduced in
successive stages and screened to separate material into
size ranges required to meet specifications.
3. The primary and secondary units are used
together to produce graded aggregate from gravel
deposits which are too large in size to be handled by the
secondary unit alone.
4. The secondary unit is used alone when the bulk
of material in a gravel deposit does not exceed 3 inches
in diameter. In this case, a positive means is provided to
limit the size of material fed to the unit.
Rarely are two aggregate production operations
exactly the same. Each project must be analyzed on the
basis of its own particular conditions and requirements.
The 75-tph plant equipment is sufficiently flexible to
meet all aggregate requirements of construction
Maintaining Quarry Equipment
Because of the working conditions around a
crushing operation, the entire crew must be totally
familiar with the manufacturers requirements and any
special conditions that may exist. This ensures proper
maintenance and the safe and productive operation of
the crusher equipment.
The entire quarry and rock production operation
depends on proper and adequate maintenance of
equipment. A regulated program of maintenance,
including step-by-step procedures, is recommended for
each piece of equipment.
In contrast to other types of construction equipment,
procurement of repair parts and new units for crushing
and screening equipment requires a much greater lead
time. Without proper parts and units, production either
slows down or stops altogether.
As the supervisor in charge of crushing and
screening operations, you must ensure operator
maintenance procedures are performed by the operators
and maintenance mechanics to ensure continuous
operation of the equipment.
Be sure the main power sources remains
OFF and are properly red-tagged while
personnel are working on electrical equipment.
Frequent inspections should be made during
operations to ensure that the equipment is not being
abused, that the units are level and cribbed, that
calibrations are correct, and that proper shutdown
procedures are followed.