CHAPTER 6
CRUSHER SUPERVISOR
Equipment is provided by the Naval Construction
Force (NCF) to enable the Seabees to meet aggregate
production requirements. Of this equipment, crushing
equipment is the critical item that provides the
capability to reduce and process material from a pit or
quarry to produce finished aggregate in sufficient
quality and quantity
to meet construction
requirements.
Seabees are tasked with crusher operations in both
Pacific and Atlantic fleet deployment sites. The Naval
Construction Training Center (NCTC), Port Hueneme,
California, provides training for crusher operations;
however, the majority of training in this area is achieved
through on-the-job-training (OJT).
The COMSECOND/COMTHlRDNCB direct the
tasking of crusher operations conducted by the Naval
Mobile Construction Battalions (NMCBs). The
NMCBs schedule a predetermined number of man-days
for crushing a variety of sizes and volumes of material
used to support construction projects, concrete plants,
crete mobiles, and asphalt plants. At the end of a
deployment, each battalion involved is usually tasked
to turn over a specified number of cubic yards of
material of various sizes to the relieving battalion. The
magnitude of the rock crusher tasking dictates the size
of the crew assigned to support the rock crusher
operations.
CRUSHER SUPERVISOR
RESPONSIBILITIES
In the Naval Construction Force (NCF), crusher
operations are usually managed by Alfa company. The
Alfa company operations chief is responsible for
crusher operations and should assign a crusher
supervisor to direct the operations of the crusher. This
chapter presents important information an EO must
master to gain the basic knowledge of rock crusher
operations required to perform the duties of a crusher
supervisor.
ROCK CRUSHER
Crushing plants
output. The most
are classified by their capacity
often used plant, classified
medium-to-large, has a rated capacity of 75 tons
per hour (tph). This plant has two separate and
distinct sets of equipment: the primary unit and
secondary unit.
The primary unit reduces the quarry rock or coarse
gravel by crushing. The secondary unit is primarily used
to process the crushed product.
The amount of crushing required to produce a
suitable amount of aggregate material depends upon the
availability of raw materials and the specifications
established for the end product. In any crusher
operations, there are four basic functions that
have to be accomplished. The four functions are as
follows:
1. Particle size reduction by crushing.
2. Separation into particle size ranges by
screening.
3. Elimination of undesirable materials by
wushing.
4. Movement of the material from one location to
another.
Primary Unit
The primary unit (fig. 6-1) consists of a
20-inch by 36-inch standard type of jaw crusher
(fig. 6-2), a vibrating grizzly, an under crusher
delivery conveyor, and a running gear. The jaw
crusher can be powered by a diesel engine or by
electrical power. All other components are driven by
individual electric
motors.
Normally, power is
supplied by a 200-kW diesel generator. The running
gear is equipped with
a fifth wheel and towing
dolly.
CAUTION
Make certain each electrically powered
component is grounded.
6-1
