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apparent plunge

The inclination of a normal projection of lineation in the plane of a
vertical cross section. CF:plunge

apparent porosity

The ratio of the volume of open pore space in a specimen to the exterior
volume.

apparent resistivity

The measured electrical resistivity between two points on the Earth's
surface, which corresponds to the sensitivity the ground would have if it
were homogeneous.

apparent specific gravity

a. Specific gravity of a rock as measured by water displacement, taking
into account the effect of sealed pore spaces as well as constituent
minerals. See also:specific gravity
b. The ratio of the weight in air of a given volume of the impermeable
portion of a permeable material (e.g., the solid matter including its
impermeable pores or voids) at a stated temperature to the weight in air
of an equal volume of distilled water at a stated temperature.
ASCE
c. This property is determined by the standard method of dividing the
weight of a rock by the weight of an equal volume of water. The term
apparent specific gravity is used because water cannot penetrate the
closed pore spaces inside the rock, and hence the specific gravity
measured by water displacement methods includes the effect of internal
pore spaces as well as that of the constituent minerals. Lewis

apparent superposition

The actual or visible order in which strata lie in any locality.
Standard, 2

apparent velocity

The velocity with which a seismic-signal wavefront appears to travel along
the surface of the Earth. It exceeds the actual velocity if the wave train
is not traveling parallel to the surface. AGI

apparent volume

True volume plus closed-pore volume. Van Vlack

apparent width

The width of a vein or other tabular formation as determined by borehole
intercepts. This width will always be greater than the true width if the
borehole intersects the vein at any direction other than perpendicular to
the surface of the vein. CF:true width

appliances of transportation

As applied to a coal mine, these include parts of the locomotive, mobile
conveyor, and elevator transportation systems for the removal of coal.

Appolt oven

An oven for the manufacture of coke, differing from the Belgian oven in
that it is divided into vertical compartments.

appraisal

The estimation or fixing of a money value on anything, such as a gemstone.
Differs from valuation and evaluation.

approach distance

The linear distance, in the direction of feed, between the point of
initial cutter contact and the point of full cutter contact.
ASM, 1

appropriation

In the mining law, the posting of notice at or near the point where the
ledge is exposed; next, the recording of the notice; next, the marking of
the boundaries. Ricketts

approved permissible flame safety lamp

A flame safety lamp that has been approved for use in gaseous coal mines.

approximate original contour

The surface configuration achieved by backfilling and grading of the mined
area so that the reclaimed area, including any terracing or access roads,
closely resembles the general surface configuration of the land prior to
mining and blends into and complements the drainage pattern of the
surrounding terrain, with all highwalls, spoil piles, and coal refuse
piles eliminated.

Apricotine

Trade name for yellowish-red, apricot-colored quartz pebbles; may be of
gem quality; near Cape May, NJ.

apron

a. A canvas-covered frame set at such an angle in a miner's rocker that
the gravel and water in passing over it are carried to the head of the
machine.
b. An amalgamated copper plate placed below a stamp battery, over which
pulp passes. The free gold contained in the pulp is amalgamated by mercury
on the plate.
c. A broad shallow vat used for evaporating. Webster 3rd
d. A receptacle or endless belt for conveying material (such as rock) by
means of a cableway and trolley. Syn:traveling apron
Webster 3rd
e. The front gate of a scraper body. Nichols, 1
f. See:morainal apron

apron conveyor

a. A series of overlapping metal plates or aprons running in an endless
chain for transferring material from one place to another. Often used to
feed raw material from a bin. ACSG, 2
b. A conveyor so contrived as to provide a moving platform on which
materials can be carried. Syn:hinged apron

apron feed

A method of feeding material forward on an articulated platform.
Nelson

apron feeder

A feeder in which the material is carried on an apron conveyor and in
which the rate of feed is adjusted either by varying the depth of material
or the speed of the conveyor, or both. See also:conveyor-type feeder
Also called plate-belt feeder; plate feeder. BS, 5

apron plate

Sheet of copper or special alloy set in front of a stamp battery and
coated with mercury to trap and amalgamate gold. Pryor, 3