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:: Coal Excise Tax - Appendix I - Glossary of Mining Terms
Appendix I - Glossary of
Mining Terms
There are many
technical terms associated with
the mining industry. Below are
terms that, while not
necessarily used or discussed in
this text, are commonly
encountered when examining
mining entities or activities.
The following definitions are
taken from "Dictionary of Mining
Terms."
A |
B |
C |
D |
E |
F |
G |
H |
I |
J |
K |
L |
M |
N |
O |
P |
Q |
R |
S |
T |
U |
V |
W
A
Abandoned
Mine - Excavations, either
caved or sealed, that are
deserted and in which further
mining is not intended.
Acid Mine
Drainage - Liquid drainage
from bituminous coal mines
containing a high concentration
of acidic sulfates, especially
ferrous sulfate.
Adit - A
horizontal opening giving access
to a mine.
Advance
Stripping - The removal of
barren or sub-grade earthy or
rock materials required to
expose and permit the minable
grade of ore to be mined.
Air Shaft
- A shaft used wholly or mainly
for ventilating mines, for
bringing fresh air to places
where men are working, or for
exhausting used air.
Airway -
Any underground gallery or
passage through which a portion
of the ventilation passes, that
is, the air is carried.
Sometimes referred to as an air
course. Also called wind road.
Anode -
The positive terminal of an
electrolytic cell. Opposite of
cathode.
Anthracite
- A hard, black lustrous coal
containing a high percentage of
fixed carbon and a low
percentage of volatile matter.
Commonly referred to as hard
coal. Anthracite ignites with
difficulty, produces no smoke,
burns at first with a very short
blue flame that disappears after
the coal is thoroughly ignited,
and produces an intensely hot
fire.
Ash -
The inorganic residue remaining
after ignition of combustible
substances. In general, it
differs in weight and
composition from the original
mineral matter.
Auger Mining
- A mining method often used by
strip-mine operators when the
overburden gets too thick to be
removed economically.
Large-diameter, spaced holes are
drilled up to 200 feet into the
coal bed by an auger. Like a bit
used for boring holes in wood,
this consists of a cutting head
with screw like extensions. As
the auger turns, the head breaks
the coal and the screw carries
the coal back into the open and
dumps it on an elevating
conveyor; this, in turn, carries
the coal to an overhead bin or
loads it directly into a truck.
Auger mining is relatively
inexpensive, and it is reported
to recover 60 to 65 percent of
the coal in the part of the bed
where it is used.
B
Backfill
- The process of filling, and/or
the material used to fill, a
mine opening. In general refers
to the material placed "back" to
refill an excavation.
Ballast
- Rough, unscreened gravel as
used to form the bed of a
railway or substratum for new
roads.
Barren
Solution - A solution from
which all possible valuable
constituents have been removed.
Bed -
The smallest division of
stratified layers marked by more
or less well-defined divisional
planes.
Belt
Conveyors - A moving endless
belt that rides on rollers and
on which coal or other materials
can be carried for various
distances.
Belt Feeders
- Short loop of conveyor belt,
or articulated steel plate, used
to draw ore at a regulated rate
from under a bin or stockpile.
Belting
- One of the main parts of a
belt conveyor. The belting
consists of plies of cotton duck
impregnated with rubber, and
with top and bottom covers of
rubber. The carrying capacity of
the belt will vary depending on
the running speed and the width
of the belt.
Bench -
The horizontal step or floor
along which coal, ore, stone, or
overburden is worked or
quarried. In tunnel excavation,
where a top heading is driven,
the bench is the mass of rock
left, extending from about the
spring line to the bottom of the
tunnel.
Beneficiation - The
processing of ores to regulate
the size of a desired product,
remove unwanted constituents,
and improve the quality, purity,
or assay grade of a desired
product. Concentration or other
preparation of ore for smelting
by drying, flotation, or
magnetic separation.
Bituminous
Coal - A coal which is high
in carbonaceous matter, having
between 15 and 50 percent
volatile matter. Also known as
soft coal.
Blast -
The operation of blasting, or
rending rock or earth by means
of explosives.
Block Coal
- A bituminous coal that breaks
into large lumps or cubical
blocks; also, coal passing over
certain sized screens instead of
through them, such as a 5-, 6-,
and 8-inch block.
Blower -
A fan employed in forcing air
either into a mine or into one
portion of a mine.
Blunging
- The wet process of blending,
or suspending, ceramic material
in liquid by agitation.
Bone Coal
- Coal with a high ash content,
almost rock.
Box Cut
- In surface mining, the initial
cut driven in a property, where
no open side exists; this
results in a high wall on both
sides of the cut.
Brattice
- A board of plank lining, or
other partition, in any mine
passage to confine the air and
force it into the working
places. Its object is to keep
the intake air from finding its
way by a short route into the
return airway.
Brattice
Cloth - Fire-resistant
canvas or duck used to erect a
brattice.
Briquet
- A block of compressed coal
dust, used as fuel; also, a slab
or block of artificial stone.
British
Thermal Unit (BTU) - The
amount of heat needed to raise 1
pound of water 1 degree F (equal
to 252 calories). Symbol, Btu.
Brown Coal
- A low-rank coal which is
brown, brownish-black, but
rarely black. It commonly
retains the structures of the
original wood. It is high in
moisture, low in heat value, and
checks badly upon drying.
Bucket -
A vessel (as a tub or scoop) for
hoisting and conveying material
(as coal, ore, grain, gravel,
mud, or concrete). A part of an
excavator that digs, lifts, and
carries dirt.
Bug Dust
- Fine coal or rock material
resulting from dry boring,
drilling, or the use of other
cutting machines in underground
work places.
Buggy -
A small wagon or truck used for
short transportation of heavy
materials (as coal in a mine or
ingots in a steel mill).
Bulldozer
(Dozer) - A highly versatile
piece of earth excavating and
moving equipment especially
useful in land clearing and
leveling work, in stripping
topsoil, in road building and
ramp building and in floor or
bench cleanup and gathering
operations.
By-product
- A secondary or additional
product; for example, the more
common byproducts of coal ovens
are gas, tar, benzol, and
ammonium sulfate.
C
Cap Lamp
- The lamp which a miner wears
on his safety hat or cap. For
illumination only.
Captive Mine
- A mine which produces coal or
mineral for use by the same
company.
Cathode
- The electrode where electrons
enter (current leaves) an
operating system, such as a
battery, an electrolytic cell,
an X-ray tube, or a vacuum tube.
Opposite of anode.
Cinder
Blocks - A block closing the
front of a blast furnace and
containing the cinder notch.
Coal - A
solid, brittle, more or less
distinctly stratified,
combustible carbonaceous rock,
formed by partial to complete
decomposition of vegetation;
varies in color from dark brown
to black; not fusible without
decomposition and very
insoluble. The boundary line
between peat and coal is hazy
(see brown coal) as is the
boundary line between coal and
graphite and the boundary line
between carbonaceous rock and
coal. In the formation of coal,
the vegetable matter appears to
have been very largely moss and
other low forms of plants, but
in places, coal contains much
wood; the vegetal matter seems
to have first taken the form of
peat, then lignite, and then
bituminous coal. The latter by
the loss of its bitumen has in
some places been converted into
anthracite (hard coal) and
finally into graphite.
Coal Fields
- An area of country, the
underlying rocks of which
contain workable coal seams.
Coal Gas
- Flammable gas derived from
coal either naturally in place,
or by induced methods of
industrial plants and
underground gasification.
Coal Seam
- A bed or stratum of coal.
Coal Tar
- Tar obtained by the
destructive distillation of
bituminous coal, usually in coke
ovens or in retorts and
consisting of numerous
constituents (as benzene,
xylenes, naphthalene, pyridine,
quinoline, phenol, cresols,
light oil, and creosote) that
may be obtained by distillation.
Coke -
Bituminous coal from which the
volatile constituents have been
driven off by heat, so that the
fixed carbon and the ash are
fused together.
Coke Breeze
- The fine screenings from
crushed coke or from coke as
taken from the ovens, of a size
varied in local practice but
usually passing a ½-inch or
3/4-inch screen opening.
Colliery
- A whole coal mining plant,
generally used in connection
with anthracite mining but
sometimes used to designate the
mine, shops, and preparation
plant of a bituminous operation.
Concentration - The process
of increasing the dissolved
solids per unit volume of
solution, usually by evaporation
of the liquid; the quantity of
solute dissolved in a unit
volume of solution.
Continuous
Mining - Mining in which the
continuous mining machine cuts
or rips coal from the face and
loads it onto conveyors or into
shuttle cars in a continuous
operation. Thus, the drilling
and shooting operations are
eliminated, along with the
necessity for working several
headings in order to have
available a heading in which
loading can be in progress at
all times. The longwall machine
and conveyor are in the same
track which is situated between
the last row of props and the
face. The conveyor is moved
forward progressively as the
coal is cut and loaded by the
machine. There are no separate
or cyclic operations as in
conventional machine mining and
the aim is to make each shift a
continuation of the previous
shift. Where the conditions are
favorable, faces up to 250 yards
in length may be so worked.
Conventional
Mining - The cycle of
operations which includes
cutting the coal, drilling the
shot holes, charging and
shooting the holes, loading the
broken coal, and installing roof
support. Also known as cyclic
mining.
Conveyor
- A mechanical contrivance
generally electrically driven,
which extends from a receiving
point to a discharge point and
conveys, transports, or
transfers material between those
points.
Core Drill
- A drilling machine equipped
with a hollow bit (core bit) and
a core barrel which by rotation
cuts out and recovers a rock
core sample. A drill that
removes a cylindrical core from
the drill hole.
Cropline
- A line following the outcrop.
Crosscut
- A small passageway driven at
right angles to the main entry
to connect it with a parallel
entry or air course.
Crusher
- A machine for crushing rock or
other materials. Among the
various types of crushers are
the ball-mill, gyratory crusher,
Hadsel mill, hammer mill, jaw
crusher, rod mill, rolls, stamp
mill, and tube mill.
Crushing
- Reducing ore or quartz by
stamps, crushers, or rolls.
Crystallization - The
formation of mineral crystals
during the cooling of a magma or
by precipitation from a
solution.
Cut - In
development work, the term cut
refers to the location and
direction of holes blasted first
to provide a free face to which
other holes may break. For
example, draw cut, horizontal
cut, pyramid cut, burned cut,
etc.
Cutting
Machine - A power-driven
machine used to undercut or
shear the coal to facilitate its
removal from the face.
D
Deep Mining
- The exploitation of coal or
mineral deposits at depths
exceeding about 3,000 feet. Also
known as underground mining.
Dragline
- A type of excavating equipment
which casts a rope-hung bucket a
considerable distance, collects
the dug material by pulling the
bucket toward itself on the
ground with a second rope,
elevates the bucket, and dumps
the material on a spoil bank, in
a hopper, or on a pile.
Dredging
- The removal of soils from
under water, using the water as
a means of transportation to
convey the soils to final
positions.
Drift -
A horizontal underground
passage. A drift follows the
vein rather than intersect it
like a crosscut.
Drill -
Any cutting tool or form of
apparatus using energy in any
one of several forms to produce
a circular hole in rock, metal,
wood, or other material.
Duckbill
- The name given to a
shaking-type combination loading
and conveying device, so named
from the shape of its loading
end and which generally receives
its motion from the shaking
conveyor to which it is
attached.
E
Empties
- Empty mine or railroad cars.
Empty railroad cars are called
"flats" in Arkansas.
Escapeway
- An opening through which the
miners may leave the mine if the
ordinary exit is obstructed.
Exhaust Fan
- A fan which sucks used air
from a mine and thereby causes
fresh air to enter by separate
entries to repeat the cycle.
F
Face - A
working place from which coal or
mineral is extracted. The
exposed surface of coal or other
mineral deposit in the working
place where mining, winning, or
getting is proceeding.
Fault -
A break in the continuity of a
body of rock. It is accompanied
by a movement on one side of the
break or the other so that what
were once parts of one
continuous rock stratum or vein
are now separated.
Fines -
In general, the smallest
particles of coal or mineral in
any classification, process, or
sample of the run-of-mine
material.
Fire -
To blast with gunpowder or other
explosives. A word shouted by
miners to warn one another when
a shot is fired.
Fire Boss
- A person designated to examine
the mine for gas and other
dangers. In certain states, the
fire boss is designated as the
mine examiner.
Floor -
The rock underlying a stratified
or nearly horizontal deposit,
corresponding to the foot wall
of more steeply dipping
deposits. A horizontal, flat ore
body.
Flotation
- The method of mineral
separation in which a froth
created in water by a variety of
reagents floats some finely
crushed minerals to the surface
and other minerals sink.
Fluidity
(Plasticity) - In mineral
transport, term not confined to
liquids and slurries, but also
used for finely divided solids
which flow readily in air
currents, fluosolids reactors,
or through dry ball mills.
Freeze Dried
Additives - Chemicals added
to the coal to prevent freezing
during shipping.
Front End
Loader - A tractor loader
with a digging bucket mounted
and operated at the front end of
the tractor. A tractor loader
that both digs and dumps in
front.
G
Gassy -
A coal mine is rated gassy by
the U.S. Bureau of Mines if an
ignition occurs or if a methane
content exceeding 0.25 percent
can be detected, and work must
be halted if the methane exceeds
1.5 percent in a return airway.
Gather -
To assemble loaded cars from
several production points and
deliver them to main haulage for
transport to the surface or pit
bottom.
Gathering
Locomotive - A lightweight
type of electric locomotive used
to haul loaded cars from the
working places to the main
haulage road, and to replace
them with empties.
Gob - To
store underground, as along one
side of a working place, the
rock and refuse encountered in
mining. The material so packed
or stored underground. The space
left by the extraction of a coal
seam into which waste is packed.
Also called goaf.
Gob Pile
- A pile or heap of mine refuse
on the surface. An accumulation
of waste material such as rock
or bone.
Gross Ton
- The long ton of 2,240
avoirdupois pounds.
Ground Water
- Water at, and below, the water
table; basal or bottom water;
phreatic water. Used also in a
broad sense to mean all water
below the ground surface. Water
derived from wells or springs,
not surface water from lakes or
streams.
Gunite -
A mixture of sand and cement,
sprayed with a pressure gun onto
roofs and ribs to act as a
sealing agent to prevent erosion
by air and moisture.
H
Haulage
- The drawing or conveying, in
cars or otherwise, or movement
of men, supplies, ore and waste
both underground and on the
surface.
Haulageway
- The gangway, entry, or tunnel
through which loaded or empty
mine cars are hauled by animal
or mechanical power.
Head House
- A covered timber framing at
the top of a shaft, into which
the shaft guides are continued
that carry the cage or elevator.
The term is sometimes applied to
the structure containing the
hoisting engine, boilers, and
other machinery, in addition to
the actual hoisting cage, etc.
Heap
Leaching - A process used
for the recovery of copper from
weathered ore and material from
mine dumps. This process can
also be applied to the sodium
sulfide leaching of mercury
ores.
Highwall
- The unexcavated face of
exposed overburden and coal or
ore in an opencast mine or the
face or bank on the uphill side
of a contour strip mine
excavation.
Hoist -
A power-driven windlass for
raising ore, rock or other
material from a mine and for
lowering or raising men and
material. Also called hoister.
I
In Situ
- In the natural or original
position. Applied to a rock,
soil, or fossil when occurring
in the situation in which it was
originally formed or deposited.
J
Jig - A
machine in which the feed is
stratified in water by means of
a pulsating motion and from
which the stratified products
are separately removed, the
pulsating motion being usually
obtained by alternate upward and
downward currents of the water.
Also called washbox.
K
Kerf -
Undercut in a coal seam from 3
to 7 inches thick and entering
the face to a depth of up to 4
feet, made by a mechanical
cutter. Also called kirve.
L
Lamp-House
- A room or building at the
surface of a mine, provided for
charging, servicing, and issuing
all cap, hand, and flame safety
lamps held at the mine.
Layout -
The design or pattern of the
main roadway and workings.
Leaching
- Extracting a soluble metallic
compound from an ore by
dissolving it in a solvent, such
as water, sulfuric acid, etc.
and then recovering the metal by
precipitation.
Lignite
- A brownish-black coal in which
the alteration of vegetal
material has proceeded further
than in peat but not so far as
subbituminous coal.
Liquid
Oxygen Explosive (LOX) -
Sawdust or other suitable
material, formed into cartridges
and dipped into liquid oxygen
before use in blasting.
Loader -
A mechanical shovel or other
machine for loading coal, ore,
mineral, or rock.
Loading
Machine - A machine for
loading materials such as coal,
ore, or rock into cars or other
means of conveyance for
transportation to the surface of
the mine.
Loading Ramp
- A surface structure, often
incorporating storage bins, used
for gravity loading bulk
material into transport
vehicles.
Locomotive
- An electric engine, either
operating from current supplied
from trolley and track or from
storage batteries carried on the
locomotive.
Longwall
- The coal seam is removed in
one operation by means of a long
working face or wall, thus the
name. The workings advance (or
retreat) in a continuous line
which may be several hundreds of
yards in length. The space from
which the coal has been removed
(the gob, goaf, or waste) is
either allowed to collapse
(caving) or is completely or
partially filled or stowed with
stone and debris. The stowing
material is obtained from any
dirt in the seam and from the
ripping operations on the
roadways to gain height. Stowing
material is sometimes brought
down from the surface and packed
by hand or by mechanical means.
Low Coal
- Coal occurring in a thin seam
or bed.
Lump Coal
- Bituminous coal in the large
lumps remaining after a single
screening that is often
designated by the size of the
mesh over which it passes and by
which the minimum size lump is
determined. Also, the largest
marketable size.
M
Man Car
- A kind of car for transporting
miners up and down the steeply
inclined shafts of some mines,
as at Lake Superior.
Man Trip
- A trip made by mine cars and
locomotives to take men rather
than coal, to and from the
working places.
Marsh Gas
- Methane gas. If the decaying
matter at the bottom of a marsh
or pond is stirred, bubbles of
methane rise to the surface,
thus the name marsh gas.
Methane
- Formed by the decomposition of
organic matter, it is the most
common gas found in coal mines.
It is a tasteless, colorless,
nonpoisonous, and odorless gas;
in mines the presence of
impurities may give it a
peculiar smell.
Methane
Monitor - A system whereby
the methane content of the mine
air is indicated automatically
at all times, and when the
content reaches a predetermined
concentration the electric power
is cut off automatically from
each machine in the affected
area. The mechanism is so
devised that its setting cannot
be altered. The system is used,
mainly, in conjunction with the
operation of continuous miners
and power loaders.
Metric Ton
- A unit of mass and weight that
equals 1,000 kilograms or
2,204.6 avoirdupois pounds;
abbreviation, MT.
Middlings
- That part of the product of a
washery, concentration, or
preparation plant which is
neither clean coal nor mineral
nor reject (tailings). It
consists of fragments of coal
and shale or mineral and gangue.
The material is often sent back
for crushing and retreatment.
Mine Car
- Cars which are loaded at
production points and hauled to
the pit bottom or surface in a
train by locomotives or other
power. They vary in capacity
from 1 to 12 tons, and are
either of wood or steel
construction or combinations of
both.
Mine Foreman
- The person charged with the
responsibility of the general
supervision of the underground
workings of a mine and the
persons employed therein. In
certain states, the mine foreman
is designated as the mine
manager.
Mine
Inspector - One who checks
mines to determine the safety
condition of working areas,
equipment, ventilation, and
electricity, and to detect fire
and dust hazards.
Miner -
One who mines; as (1) one
engaged in the business or
occupation of getting ore, coal,
precious substances, or other
natural substances out of the
earth; (2) a machine for
automatic mining (as of coal);
and (3) a worker on the
construction of underground
tunnels and shafts (as for
roads, railways, waterways).
Mineral
- In a broad nontechnical sense,
the term embraces all inorganic
and organic substances that are
extracted from the earth for use
by man. A substance occurring in
nature which has a definite or
characteristic range of chemical
composition, and distinctive
physical properties or molecular
structure. With few exceptions,
such as opal and mercury,
minerals are crystalline solids.
Mineral
Rights - The ownership of
the minerals under a given
surface, with the right to enter
thereon, mine, and remove them.
It may be separated from the
surface ownership, but, if not
so separated by distinct
conveyance, the latter includes
it.
Mine Run
- The product of the mines
before being sized and cleaned.
Mouth -
An opening resembling or likened
to a mouth, as one affording
entrance or exit to a mine.
Muck -
Unconsolidated soils, sand,
clays, loams encountered in
surface mining; generally, earth
which can be severed and moved
without preliminary blasting.
Useless material; earth or rock
which may or may not be mixed
with coal or minerals.
Multiple-Seam Mining -
Mining two or more seams of
coal, frequently close together,
that can be mined profitably
where mining one alone would not
be profitable.
N
Nonmetal
- A chemical element that is not
classed as a metal because it
does not exhibit most of the
typical metallic properties. An
element that, in general, is
characterized chemically by the
ability to form anions, acidic
oxides and acids, and stable
compounds with hydrogen.
O
Open-Cut
(Pit) Mining - A form of
operation designed to extract
minerals that lie near the
surface. Waste, or overburden,
is first removed, and the
mineral is broken and loaded, as
in a stone quarry. Important
chiefly in the mining of ores of
iron and copper. The mining of
metalliferous ores by
surface-mining methods is
commonly designated as "open-pit
mining" as distinguished from
the "strip mining" of coal and
the "quarrying" of other
nonmetallic materials such as
limestone, building stone, etc.
Opening
- A short heading driven between
two or more parallel headings or
levels for ventilation.
Outcrop
- A term used in connection with
a vein or lode as an essential
part of the definition of apex.
It does not necessarily imply
the visible presentation of the
mineral on the surface of the
earth, but includes those
deposits that are so near to the
surface as to be found easily by
digging.
Overburden
- Used by geologists and
engineers in several different
senses. By some, it is used to
designate material of any
nature, consolidated or
unconsolidated, that overlies a
deposit of useful materials,
ores, or coal, especially those
deposits that are mined from the
surface by open cuts. By others,
overburden designates only loose
soil, sand, gravel, etc., that
lies above the bedrock. The term
should not be used without
specific definition. Also called
burden, cover, drift, mantle,
surface.
Overriding
Royalty - The term applied
to a royalty reserved in a
sublease or assignment over and
above that reserved in the
original lease.
P
Panel -
System of coal extraction in
which the ground is laid off in
separate districts or panels,
pillars of extra size being left
between.
Parting
- A natural, usually smooth,
separation between strata.
Peat -
There are two types of peat, low
moor (Flachmoor) and high moor
(Hochmoor) peat. Low moor peat
is the most common starting
material in coal genesis. It
therefore constitutes a
caustobiolith of low diagenetic
degree. Peat is formed in
marshes and swamps from the
dead, and partly decomposed
remains of the marsh
vegetation. Stagnant ground
water is necessary for peat
formation to protect the
residual plant material from
decay. Peat has a yellowish
brown to brownish black color,
is generally of the fibrous
consistency, and can be either
plastic or friable; in its
natural state it can be cut;
further, it has a very high
moisture content (above 75
percent, generally above 90
percent). It can be
distinguished from brown coal by
the fact that the greater part
of its moisture content can be
squeezed out by pressure (for
example, in the hand). Peat also
contains more plant material in
a reasonably good state of
preservation than brown coal.
Pillar -
An area of coal or ore left to
support the overlying strata or
hanging-wall in a mine. Pillars
are sometimes left permanently
to support surface works or
against old workings containing
water. Coal pillars, such as
those in pillar-and-stall
mining, are extracted at a later
period.
Pit -
Any mine, quarry, or excavation
area worked by the open-cut
method to obtain material of
value.
Pit
Committee - A joint
committee of employer and
workers dealing with the labor
problems of a mine.
Place -
The part of a mine in which a
miner works by contract is known
as his "place" or "working
place." A point at which the
cutting of coal is being carried
on.
Portal -
Any entrance to a mine. The rock
face at which tunnel driving is
started. Also called point of
attack. A nearly level opening
into a tunnel. The surface
entrance to a drift, tunnel,
adit, or entry.
Portal to
Portal - A term now
frequently encountered in
disputes over what constitutes
compensable "working time" under
Federal laws. Portal literally
means "entrance" and, in
underground coal mining, portal
refers to mine mouth or entry at
surface. Hence,
portal-to-portal as a
descriptive term means strictly
elapsed time from entry through
the portal to exit on return.
Post - A
mine timber, or any upright
timber, but more commonly used
to refer to the uprights which
support the roof cross-pieces.
Commonly used in metal mines
instead of leg which is the coal
miner's term, especially in the
Far West regions of the United
States. The support fastened
between the roof and floor of a
coal seam used with certain
types of mining machines or
augers. A pillar of coal or ore.
Powdered
Coal (Pulverized Coal) -
Coal that has been crushed to a
fine dust by grinding mills.
The latter are often air swept,
the velocity of the air being so
regulated that particles of
coal, when sufficiently reduced,
are carried away. Pulverized
coal particles of which about 99
percent are below 0.01 inch in
diameter will burn very rapidly
and efficiently. Low-grade coal
may be pulverized and conveyed
from the mill by air into the
boiler plant.
Power Shovel
- An excavating and loading
machine consisting of a digging
bucket at the end of an arm
suspended from a boom, which
extends crane-like from that
part of the machine which houses
the power plant. When digging
the bucket moves forward and
upward so that the machine does
not usually excavate below the
level at which it stands.
Pregnant
Solution - A value-bearing
solution in a hydrometallurgical
operation.
Preparation
Plant - Strictly speaking, a
preparation plant may be any
facility where coal is prepared
for market, but by common usage
it has come to mean a rather
elaborate collection of
facilities where coal is
separated from its impurities,
washed and sized, and loaded for
shipment.
Proximate
Analysis - The determination
of the compounds contained in a
mixture as distinguished from
ultimate analysis, which is the
determination of the elements
contained in a compound. Used in
the analysis of coal.
Q
Quarrying
- The surface exploitation of
stone or mineral deposits from
the earth's crust. Removal of
rock which has value because of
its physical characteristics.
R
Reclamation
- The costs incurred to restore
land to its original (or better)
condition.
Rock Dusting
- The dusting of underground
areas with powdered limestone to
dilute the coal dust in the mine
atmosphere thereby reducing
explosion hazards.
Roll -
Used to describe minor
deformations or dislocations of
a coal seam, for example, faults
with small displacement to small
monoclinal folds, to welts or
ridges projecting from either
the roof or floor into the coal,
and to fillings of stream
channels or low areas extending
downward into the coal.
Roof Bolting
(Pinning) - A system of roof
support in mines. Boreholes from
3 to 8 feet long are drilled
upward in the roof and bolts of
1 inch diameter or more are
inserted into the holes and
anchored at the top by a split
cone or similar device. The bolt
end protrudes below roof level
and is used to support roof
bars, girders, or simple steel
plates pulled tight up to the
roof by a nut on the bolt head.
The bolts are put up to a
definite pattern. The idea is to
clamp together the several roof
beds to form a composite beam
with a strength considerably
greater than the sum of the
individual beds acting
separately.
Room - A
place abutting an entry or
airway where coal has been mined
and extending from the entry or
airway to a face.
Room and
Pillar - A system of mining
in which the distinguishing
feature is the winning of 50
percent or more of the coal or
ore in the first working. The
coal or ore is mined in rooms
separated by narrow ribs or
pillars. The coal or ore in the
pillars is won by subsequent
working, which may be likened to
top slicing, in which the roof
is caved in successive blocks.
The first working in rooms is an
advancing, and the winning of
the rib (pillar) a retreating
method. The rooms are driven
parallel with one another, and
the room faces may be extended
parallel, at right angles, or at
an angle to the dip. This method
is applicable to flat deposits,
such as coal, iron ore, lead,
zinc, etc., that occur in bedded
deposits.
Rotary Dump
- An apparatus for overturning
one or more mine cars
simultaneously to discharge
coal. They may rotate either 180
degrees or 360 degrees.
Royalty
- A share of the product or
profit reserved by the owner for
permitting another to use the
property. A lease by which the
owner or lessor grants to the
lessee the privilege of mining
and operating the land in
consideration of the payment of
a certain stipulated royalty on
the mineral produced.
Runoff -
That portion of the rainfall
that is not absorbed by the
strata; is utilized by
vegetation or lost by
evaporation or may find its way
into streams as surface flow.
S
Scraper
Loader - A machine used for
loading coal or rock by pulling
an open-bottomed scoop back and
forth between the face and the
loading point by means of ropes,
sheaves, and a multiple drum
hoist. The filled scoop is
pulled on the bottom to an apron
or ramp where the load is
discharged onto a car or
conveyor.
Screen -
A large sieve for grading or
sizing coal, ore, rock, or
aggregate. It consists of a
suitably mounted surface of
woven wire or of punched plate.
It may be flat or cylindrical,
horizontal or inclined,
stationary, shaking, or
vibratory, and either wet or dry
operation.
Screenings
- Coal which will pass through
the smallest mesh screen
normally loaded for commercial
sale for industrial use.
Seam - A
stratum or bed of coal or other
mineral; generally applied to
large deposits of coal.
Shaft -
An excavation of limited area
compared with its depth, made
for finding or mining ore or
coal, raising water, ore, rock,
or coal, hoisting and lowering
men and material, or ventilating
underground workings. The term
is often specifically applied to
approximately vertical shafts,
as distinguished from an incline
or inclined shaft. A shaft is
provided with a hoisting engine
at the top for handling men,
rock, and supplies, or it may be
used only in connection with
pumping or ventilating
operations.
Shaker
Conveyor - A conveyor
consisting of a length of metal
troughs, with suitable supports,
to which a reciprocating motion
is imparted by drives. In the
case of a downhill conveyor, a
simple to-and-fro motion is
sufficient to cause the coal to
slide. With a level or a slight
uphill gradient, a differential
motion is necessary, that is, a
quick backward and slower
forward strokes. The quick
backward stroke causes the
trough to slide under the coal,
while the slower forward stroke
moves the coal along to a new
position. Also called jigger.
Shale -
A laminated sediment, in which
the constituent particles are
predominantly of the clay grade.
Shearing
- Making a vertical cut or
groove in a coal face, breast,
or block, as opposed to a kerf,
which is a horizontal cut.
Called in Arkansas as cut or
cutting.
Shoot -
To break coal loose from the
seam by the use of explosives;
loosely used, also as applied to
other coal breaking devices.
Shooter
- The person who fires a charged
hole after satisfying
himself/herself that the area is
free from firedamp. A shot
firer.
Short Ton
- A unit of weight that equals
20 short hundredweights or 2,000
avoirdupois pounds. Used chiefly
in the United States, in Canada,
and in the Republic of South
Africa.
Shortwall
- The reverse of longwall,
frequently used to mean the face
of a room. A method of mining in
which comparatively small areas
are worked separately, as
opposed to longwall; for
example, room and pillar.
Shot Firer
- A person whose special duty is
to fire shots or blasts,
especially in coal mines. A shot
lighter.
Shovel -
Any bucket-equipped machine used
for digging and loading earthy
or fragmented rock materials.
There are two types of shovels,
the square-point and the
round-point. These are
available with either long or
short handles. The round-point
shovel is used for general
digging since its forward edge,
curved to a point, most readily
penetrates moist clays and
sands. The square-point shovel
is used for shoveling against
hard surfaces or for trimming.
Shuttle Car
- A vehicle on rubber tires or
caterpillar treads and usually
propelled by electric motors,
electrical energy which is
supplied by a diesel-driven
generator, by storage batteries,
or by a power distribution
system through a portable cable.
Its chief function is the
transfer of raw materials, such
as coal and ore, from loading
machines in trackless areas of a
mine to the main transportation
system.
Silt - A
fine-grained sediment having a
particle size intermediate
between that of fine sand and
clay.
Slack -
Small coal, usually less than
1/8 inch. It has a high ash
content and is difficult to
clean in the washery. High ash
slack is being used increasingly
in special boilers and power
stations.
Slice -
In an ore body of considerable
lateral extent and thickness,
the ore is removed in layers
termed slices.
Slope -
The main working gallery or
entry of a coal seam which dips
at an angle and along which mine
cars are hauled. An entrance to
a mine driven down through an
inclined coal seam; also, a mine
having such an entrance.
Slope Mine
- A mine with an inclined
opening used for the same
purpose as a shaft or a drift
mine. It resembles a tunnel, a
drift, or a shaft, depending on
its inclination.
Sludge -
Mineral, mud, and slurry too
thick to flow. A soft mud,
slush, or mire; for example the
solid product of a filtration
process before drying (filter
cake).
Slurry -
The fine carbonaceous discharge
from a colliery washery. All
washeries produce some slurry
which must be treated to
separate the solids from the
water in order to have a clear
effluent for reuse or discharge.
Also, in some cases, it is
economical to extract the fine
coal from the effluent.
Spoil Bank
- To leave coal and other
minerals that are not marketable
in the mine.
Stoker Coal
- A screen size of coal
specifically for use in
automatic firing equipment. This
coal can be of any rank and the
stoker is usually designed to
fit the coal available. Factors
of importance in the selection
of coal for stoker use are: size
limits, size consist, uniformity
of shipments, coking properties,
ash fusion characteristics, ash,
sulfur and volatile-matter
percentages.
Strip -
In coal mining, to remove the
earth, rock, and other material
from a seam of coal, generally
by power shovels. Generally
practiced only where the coal
seam lies close to the earth's
surface. To remove from a
quarry, or other open working,
the overlying earth and
disintegrated or barren surface
rock.
Strip Mine
- An opencut mine in which the
overburden is removed from a
coal bed before the coal is
taken out.
Subsidence
- A sinking down of a part of
the earth's crust. The lowering
of the strata, including the
surface, due to underground
excavations. Surface caving or
distortion due to effects of
collapse of deep workings.
Surface
Mining - The mining in
surface excavations. It includes
placer mining, mining in open
glory-hole or milling pits,
mining and removing ore from
open cuts by hand or with
mechanical excavation and
transportation equipment, and
the removal of capping or
overburden to uncover the ores.
Mining at or near the surface.
This type of mining is generally
done where the overburden can be
removed without too much
expense. Also called strip
mining, placer mining, opencast
mining, opencut mining, or
open-pit mining.
Surface
Rights - The ownership of
the surface of land only, where
mineral rights are reserved.
Those reserved to the owner of
the land beneath which ore is
being mined. The right of a
mineral owner or an oil and gas
lessee to use so much of the
surface of land as may be
reasonably necessary for the
conduct of operations under the
lease.
T
Timber -
Any of the wooden props, posts,
bars, collars, lagging, etc.,
used to support mining works.
One of the steel joists or beams
which, in some mines, have
replaced wooden timbers.
Timbering
- The operation of setting
timber supports in mine workings
or shafts. The term support
would cover the setting of
timber, steel, concrete, or
masonry supports.
Timbering
Machine - An electrically
driven machine to raise and hold
timbers in place while
supporting posts are being set
after cut to length by the
machine's power-driven saw.
Tipple -
Originally the place where the
mine cars were tipped and
emptied of their coal, and still
used in that sense, although now
more generally applied to the
surface structures of a mine,
including the preparation plant
and loading tracks.
Trailing
Cables - A flexible electric
cable for connecting portable
face machines and equipment to
the source of supply located
some distance outby. The cable
is heavily insulated and
protected with either galvanized
steel wire armoring, extra stout
braiding hosepipe, or other
material.
Trolley Wire
- The means by which power is
conveyed to an electric trolley
locomotive. It is hung from the
roof and conducts power to the
locomotive by the trolley pole.
Power from it is sometimes also
used to run other equipment.
U
Undercut
- Excavation of ore from beneath
a larger block of ore to induce
its settlement under its own
weight.
V
Vein - A
zone or belt of mineralized rock
lying within boundaries clearly
separating it from neighboring
rock. It includes all deposits
of mineral matter found through
a mineralized zone or belt
coming from the same source,
impressed with the same forms
and appearing to have been
created by the same processes. A
mineralized zone having a more
or less regular development in
length, width, and depth to give
it a tabular form and commonly
inclined at a considerable angle
to the horizontal. The term lode
is commonly used synonymously
for vein.
Volatile
Matter - Those products,
exclusive of moisture, given off
by a material as gas and vapor,
determined by definite
prescribed methods which may
vary according to the nature of
the material. In the case of
coal and coke, the methods
employed shall be those
prescribed in the Standard
Methods of Laboratory Sampling
and Analysis of Coal and Coke
(ASTM Designation D271) of the
American Society for Testing
Materials.
W
Wall -
The side of a lode; the
overhanging side is know as the
hanging wall and the lower lying
side as the footwall. The face
of a longwall working or stall,
commonly called coal wall. A rib
of solid coal between two rooms;
also, the side of an entry.
Washery
- A place at which ore, coal, or
crushed stone is freed from
impurities or dust by washing.
Also called wet separation
plant.
Wheel
Excavator - A large-capacity
machine for excavating loose
deposits, particularly at
quarries and opencast coalpits.
It consists of a digging wheel,
rotating on a horizontal axle,
and carrying large buckets on
its rim.
Wire Rod
- Hot-rolled coiled stock that
is made into wire.
Working
Place - The place in a mine
at which coal or ore is being
actually mined.
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