This chapter provides information on the selection
and operations of pits and quarries. It describes basic
principles of site selection, preparation, and methods
and techniques of developing pits and quarries.
Pit and quarry operations in the Naval Construction
Force (NCF) are normally managed by Alfa company.
The operations chief of Alfa company is usually
responsible for the pit and quarry operations and
normally assigns a quarry supervisor to direct the
operations of the pit and quarry.
PITS AND QUARRIES
The operation of the pit and quarry is directly
determined by the material requirements and tasking for
construction projects and rock crushing operations. The
size of the crew assigned to support the pit or quarry
operations is dictated by the availability of the
equipment and material required for a construction task.
Pits and quarries are classified according to the type
of material they contain and the methods used to
excavate and process the material (table 5-1).
Pits are excavations made at the earths surface in
unconsolidated materials, such as clay, sand, gravel,
coral, and laterite. They are sites from which suitable
construction materials are obtained in quantity, being
removed or extracted from the surface without the use
of blasting. Alluvial or stream-deposited gravel pits
yield gravel that is usually clean and free of clay and
humus and are therefore desirable for concrete and
bituminous work. Bank or hill gravel pits yield a clayey
gravel that is desirable for road or runway surfacing
because of its binding qualities. Gravel is also used for
base courses and fills. Soil (other than sand and gravel)
selected for use in embankments, fills, and subgrades is
obtained from borrow pits. Miscellaneous pits contain
mixed tailings, slag, cinders, or the like, which are also
used for road or runway surfacing and as aggregates.
Quarries are sites where large, open excavations are
made for the purpose of extracting or removing rock in
its natural state by drilling, cutting, and blasting. In some
cases, it may be possible to remove and break up rock
by use of dozer rippers and bull pricks (jack hammer
attachment). The primary types of rocks obtained from
quarries are igneous and metamorphic, such as trap rock,
granite, diorite, geneiss, quartize, and certain shales.
Military quarries are generally open-faced, which
means the vertical surface of the rock is exposed. Since
seldom used in its inplace state, quarry rock is processed
with mobile equipment that crushes, screens, and
Before a pit or quarry is located, an investigation of
the site must be performed to establish that suitable
construction materials are available in adequate
amounts and that the excavation can be worked
efficiently with available equipment. Whenever
possible, existing pits and quarries are used because (1)
the quantity and quality of materials can easily be
determined; (2) good haul and access roads are probably
already built; (3) less effort can be spent on removal of
overburden; and (4) facilities, such as ramps, hoppers,
bins, power, and water, are generally available.
The chosen site should be as close as possible to the
construction project and convenient to good routes of
transportation. This allows more efficient hauling by
decreasing the length of haul roads. Pit and quarry
haulage is usually accomplished with equipment, such
as dump trucks and scrapers.
The formation of soil is a continuous process.
Basically, the crust of the earth consists of rock that
geologists classify into three groups: igneous, which is
formed by cooling from a molten state; sedimentary,
formed by the accumulation and cementing of existing
particles and remains of plants and animals; and
metamorphic, formed from existing rocks that have
been subjected to heat and pressure. When the rock is