B
Back - The roof or upper part in any underground mining cavity.
Backfill – Mine waste or rock used to support the roof after coal
removal.
Barren - Said of rock or vein material containing no minerals of
value, and of strata without coal, or containing coal in seams too thin to
be workable.
Barricading - Enclosing part of a mine to prevent inflow of
noxious gasses from a mine fire or an explosion.
Barrier - Something that bars or keeps out. Barrier pillars are
solid blocks of coal left between two mines or sections of a mine to prevent
accidents due to inrushes of water, gas, or from explosions or a mine fire.
Beam - A bar or straight girder used to support a span of roof
between two support props or walls.
Beam building - The creation of a strong, inflexible beam by
bolting or otherwise fastening together several weaker layers. In coal
mining this is the intended basis for roof bolting.
Bearing – A surveying term used to designate direction. The
bearing of a line is the acute horizontal angle between the meridian and the
line. The meridian is an established line of reference. Azimuths are angles
measured clockwise from any meridian.
Bearing plate - A plate used to distribute a given load. In roof
bolting, the plate used between the bolt head and the roof.
Bed - A stratum of coal or other sedimentary deposit.
Belt conveyor - A looped belt on which coal or other materials can
be carried and which is generally constructed of flame-resistant material or
of reinforced rubber or rubber-like substance.
Belt idler - A roller, usually of cylindrical shape, which is
supported on a frame and which, in turn, supports or guides a conveyor belt.
Idlers are not powered but turn by contact with the moving belt.
Belt take-up - A belt pulley, generally under a conveyor belt and
inby the drive pulley, kept under strong tension parallel to the belt line.
Its purpose is to automatically compensate for any slack in the belting
created by start-up, etc.
Bench - One of to or more divisions of a coal seam separated by
slate or formed by the process of cutting the coal.
Beneficiation - The treatment of mined material, making it more
concentrated or richer.
Berm - A pile or mound of material capable of restraining a
vehicle.
Binder - A streak of impurity in a coal seam.
Bit - The hardened and strengthened device at the end of a drill
rod that transmits the energy of breakage to the rock. The size of the bit
determines the size of the hole. A bit may be either detachable from or
integral with its supporting drill rod.
Bituminous coal – A middle rank coal
(between subbituminous and anthracite) formed by additional pressure and
heat on lignite. Usually has a high Btu value and may be referred to as
"soft coal." A general term descriptive of coal intermediate in rank between
sub-bituminous and anthracite and including metallurgical coals. Low and
medium volatile bituminous coals are ranked by their carbon content, while
high volatile bituminous coals are ranked by their heating value.
Black damp - A term generally applied to carbon dioxide. Strictly
speaking, it is a mixture of carbon dioxide and nitrogen. It is also applied
to an atmosphere depleted of oxygen, rather than having an excess of carbon
dioxide.
Blasting agent - Any material consisting of a mixture of a fuel
and an oxidizer.
Blasting cap - A detonator containing a charge of detonating
compound, which is ignited by electric current or the spark of a fuse. Used
for detonating explosives.
Blasting circuit - Electric circuits used to fire electric
detonators or to ignite an igniter cord by means of an electric starter.
Bleeder or bleeder entries - Special air courses developed and
maintained as part of the mine ventilation system and designed to
continuously move air-methane mixtures emitted by the gob or at the active
face away from the active workings and into mine-return air courses. Alt:
Exhaust ventilation lateral.
Boiler - A tank in which water is heated or
steam is generated.
Bolt torque - The turning force in foot-pounds applied to a roof
bolt to achieve an installed tension.
Borehole - Any deep or long drill-hole, usually associated with a
diamond drill.
Bottom - Floor or underlying surface of an underground excavation.
Boss - Any member of the managerial ranks who is directly in
charge of miners (e.g., "shift-boss," "face-boss," "fire-boss," etc.).
Box-type magazine - A small, portable magazine used to store
limited quantities of explosives or detonators for short periods of time at
locations in the mine which are convenient to the blasting sites at which
they will be used.
Brattice or brattice cloth - Fire-resistant fabric or plastic
partition used in a mine passage to confine the air and force it into the
working place. Also termed "line brattice," "line canvas," or "line
curtain."
Break line - The line that roughly follows the rear edges of coal
pillars that are being mined. The line along which the roof of a coal mine
is expected to break.
Breaker - A machine which combines coal
crushing and screening. Normally consists of a rotating drum in which coal
is broken by gravity impact against the walls of the drum.
Breakthrough - A passage for ventilation that is cut through the
pillars between rooms.
Bridge carrier - A rubber-tire-mounted mobile conveyor, about 10
meters long, used as an intermediate unit to create a system of articulated
conveyors between a mining machine and a room or entry conveyor.
Bridge conveyor - A short conveyor hung from the boom of mining or
lading machine or haulage system with the other end attached to a receiving
bin that dollies along a frame supported by the room or entry conveyor,
tailpiece. Thus, as the machine boom moves, the bridge conveyor keeps it in
constant connection with the tailpiece.
Brow - A low place in the roof of a mine, giving insufficient
headroom.
Brushing - Digging up the bottom or taking down the top to give
more headroom in roadways.
Btu – British thermal unit. A measure of the
energy required to raise the temperature of one pound of water one degree
Fahrenheit.
Bug dust - The fine particles of coal or other material resulting
form the boring or cutting of the coal face by drill or machine.
Bump (or burst) - A violent dislocation of the mine workings which
is attributed to severe stresses in the rock surrounding the workings.
Butt cleat - A short, poorly defined vertical cleavage plane in a
coal seam, usually at right angles to the long face cleat.
Butt entry - A coal mining term that has different meanings in
different locations. It can be synonymous with panel entry, submain entry,
or in its older sense it refers to an entry that is "butt" onto the coal
cleavage (that is, at right angles to the face).
C
Cage - In a mine shaft, the device, similar to an elevator car,
that is used for hoisting personnel and materials.
Calorific value - The quantity of heat that can be liberated from
one pound of coal or oil measured in BTU's.
Cannel coal - A massive, non-caking block coal with a fine, even
grain and a conchoidal fracture which has a high percentage of hydrogen,
burns with a long, yellow flame, and is extremely easy to ignite.
Canopy - A protective covering of a cab on a mining machine.
Cap - A miner's safety helmet. Also, a highly sensitive,
encapsulated explosive that is used to detonate larger but less sensitive
explosives.
Cap block - A flat piece of wood inserted between the top of the
prop and the roof to provide bearing support.
Car - A railway wagon, especially any of the wagons adapted to
carrying coal, ore, and waste underground.
Car-dump - The mechanism for unloading a loaded car.
Carbide bit - More correctly, cemented tungsten carbide. A cutting
or drilling bit for rock or coal, made by fusing an insert of molded
tungsten carbide to the cutting edge of a steel bit shank.
Carbon Dioxide - A colorless,
odorless, non-toxic radiative gas that is essential to plant and animal
life. It is also emitted as a result of burning organic materials, including
fossil fuels.
Cast - A directed throw; in strip-mining, the overburden is cast
from the coal to the previously mined area.
Certified - Describes a person who has passed an examination to do
a required job.
Chain conveyor - A conveyor on which the material is moved along
solid pans (troughs) by the action of scraper crossbars attached to powered
chains.
Chain pillar - The pillar of coal left to protect the gangway or
entry and the parallel airways.
Charcoal - The residue, primarily carbon,
from the partial combustion of wood or other organic matter.
Check curtain - Sheet of brattice cloth hung across an airway to
control the passage of the air current.
Chlorofluorocarbons (CFCs) -
Human-produced chemical compounds containing chlorine, fluorine and carbon
which are thought to be responsible for ozone-layer depletion. CFCs also act
as a radiative gas.
Chock - Large hydraulic jacks used to support roof in longwall and
shortwall mining systems.
Clay vein - A body of clay-like material that fills a void in a
coal bed.
Cleat - The vertical cleavage of coal seams. The main set of
joints along which coal breaks when mined.
Clean Air Act Amendments of 1990 – A comprehensive set of
amendments to the federal law governing the nation's air quality. The Clean
Air Act was originally passed in 1970 to address significant air pollution
problems in our cities. The 1990 amendments broadened and strengthened the
original law to address specific problems such as acid deposition, urban
smog, hazardous air pollutants and stratospheric ozone depletion.
Clean Coal Technologies – A number of innovative, new technologies
designed to use coal in a more efficient and cost-effective manner while
enhancing environmental protection. Several promising technologies include:
fluidized-bed combustion, integrated gasification combined cycle, limestone
injection multi-stage burner, enhanced flue gas desulfurization (or
"scrubbing"), coal liquefaction and coal gasification.
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.
Coal desulphurisation - Removal of
sulphur from coal or coal gas.
Coal dust - Particles of coal that can
pass a No. 20 sieve.
Coal Gasification – The conversion of coal into a gaseous fuel.
Coal mine - An area of land and all structures, facilities,
machinery, tools, equipment, shafts, slopes, tunnels, excavations, and other
property, real or personal, placed upon, under, or above the surface of such
land by any person, used in extracting coal from its natural deposits in the
earth by any means or method, and the work of preparing the coal so
extracted, including coal preparation facilities. British term is
"colliery".
Coal reserves - Measured tonnages of coal that have been
calculated to occur in a coal seam within a particular property.
Coal washing – The process of separating undesirable materials
from coal based on differences in densities. Pyritic sulfur, or sulfur
combined with iron, is heavier and sinks in water; coal is lighter and
floats.
Coke – A hard, dry carbon substance produced by
heating coal to a very high temperature in the absence of air. Coke is used
in the manufacture of iron and steel.
Collar - The term applied to the timbering or concrete around the
mouth or top of a shaft. The beginning point of a shaft or drill hole at the
surface.
Colliery - British name for coal mine.
Column flotation – A precombustion coal cleaning technology in
which coal particles attach to air bubbles rising in a vertical column. The
coal is then removed at the top of the column.
Combustion chamber - The part
of a boiler in which fuel is burned.
Comminution - The breaking, crushing, or grinding of coal, ore, or
rock.
Competent rock - Rock which, because of its physical and
geological characteristics, is capable of sustaining openings without any
structural support except pillars and walls left during mining (stalls,
light props, and roof bolts are not considered structural support).
Contact - The place or surface where two different kinds of rocks
meet. Applies to sedimentary rocks, as the contact between a limestone and a
sandstone, for example, and to metamorphic rocks; and it is especially
applicable between igneous intrusions and their walls.
Continuous miner - A machine that constantly extracts coal while
it loads it. This is to be distinguished from a conventional, or cyclic,
unit which must stop the extraction process in order for loading to
commence.
Contour - An imaginary line that connects all points on a surface
having the same elevation.
Conventional mining – The first fully-mechanized underground
mining method involving the insertion of explosives in a coal seam, the
blasting of the seam, and the removal of the coal onto a conveyor or shuttle
car by a loading machine.
Conveyor - An apparatus for moving material from one point to
another in a continuous fashion. This is accomplished with an endless (that
is, looped) procession of hooks, buckets, wide rubber belt, etc.
Core sample – A cylinder sample generally 1-5" in diameter drilled
out of an area to determine the geologic and chemical analysis of the
overburden and coal.
Cover - The overburden of any deposit.
Creep - The forcing of pillars into soft bottom by the weight of a
strong roof. In surface mining, a very slow movement of slopes downhill.
Crib - A roof support of prop timbers or ties, laid in alternate
cross-layers, log-cabin style. It may or may not be filled with debris. Also
may be called a chock or cog.
Cribbing - The construction of cribs or timbers laid at right
angles to each other, sometimes filled with earth, as a roof support or as a
support for machinery.
Crop coal - Coal at the outcrop of the seam. It is usually
considered of inferior quality due to partial oxidation, although this is
not always the case.
Crossbar - The horizontal member of a roof timber set supported by
props located either on roadways or at the face.
Crosscut - A passageway driven between the entry and its parallel
air course or air courses for ventilation purposes. Also, a tunnel driven
from one seam to another through or across the intervening measures;
sometimes called "crosscut tunnel", or "breakthrough". In vein mining, an
entry perpendicular to the vein.
Cross entry - An entry running at an angle with the main entry.
Crusher - A machine for crushing rock or other materials. Among
the various types of crushers are the ball mill, gyratory crusher, Handsel
mill, hammer mill, jaw crusher, rod mill, rolls, stamp mill, and tube mill.
Cutter; Cutting machine - A machine, usually used in coal, that
will cut a 10- to 15-cm slot. The slot allows room for expansion of the
broken coal. Also applies to the man who operates the machine and to workers
engaged in the cutting of coal by prick or drill.
Cycle mining - A system of mining in more than one working place
at a time, that is, a miner takes a lift from the face and moves to another
face while permanent roof support is established in the previous working
face.
D
Demonstrated reserves – A collective term for the sum of coal in
both measured and indicated resources and reserves.
Deposit - Mineral deposit or ore deposit is used to designate a
natural occurrence of a useful mineral, or an ore, in sufficient extent and
degree of concentration to invite exploitation.
Depth - The word alone generally denotes vertical depth below the
surface. In the case of incline shafts and boreholes it may mean the
distance reached from the beginning of the shaft or hole, the borehole
depth, or the inclined depth.
Detectors - Specialized chemical or electronic instruments used to
detect mine gases.
Detonator - A device containing a small detonating charge that is
used for detonating an explosive, including, but not limited to, blasting
caps, exploders, electric detonators, and delay electric blasting caps.
Development mining - Work undertaken to open up coal reserves as
distinguished from the work of actual coal extraction.
Diffusion - Blending of a gas and air, resulting in a homogeneous
mixture. Blending of two or more gases.
Diffuser fan - A fan mounted on a continuous miner to assist and
direct air delivery from the machine to the face.
Dilute - To lower the concentration of a mixture; in this case the
concentration of any hazardous gas in mine air by addition of fresh intake
air.
Dilution - The contamination of ore with barren wall rock in
stoping.
Dip - The inclination of a geologic structure (bed, vein, fault,
etc.) from the horizontal; dip is always measured downwards at right angles
to the strike.
Dragline – A large excavation machine used
in surface mining to remove overburden (layers of rock and soil) covering a
coal seam. The dragline casts a wire rope-hung bucket a considerable
distance, collects the dug material by pulling the bucket toward itself on
the ground with a second wire rope (or chain), elevates the bucket, and
dumps the material on a spoil bank, in a hopper, or on a pile.
Drainage - The process of removing surplus ground or surface water
either by artificial means or by gravity flow.
Draw slate - A soft slate, shale, or rock from approximately 1 cm
to 10 cm thick and located immediately above certain coal seams, which falls
quite easily when the coal support is withdrawn.
Drift - A horizontal passage underground. A drift follows the
vein, as distinguished from a crosscut that intersects it, or a level or
gallery, which may do either.
Drift mine – An underground coal mine in which the entry or access
is above water level and generally on the slope of a hill, driven
horizontally into a coal seam.
Drill - A machine utilizing rotation, percussion (hammering), or a
combination of both to make holes. If the hole is much over 0.4m in
diameter, the machine is called a borer.
Drilling - The use of such a machine to create holes for
exploration or for loading with explosives.
Dummy - A bag filled with sand, clay, etc., used for stemming a
charged hole.
Dump - To unload; specifically, a load of coal or waste; the
mechanism for unloading, e.g. a car dump (sometimes called tipple); or, the
pile created by such unloading, e.g. a waste dump (also called heap, pile,
tip, spoil pike, etc.).
E
Electrical grounding - To connect with the ground to make the
earth part of the circuit.
Electrostatic precipitator - An
electrical device for removing fine particles (fly ash) from combustion
gases prior to release from a power plant's stack.
Energy - The capacity to do work; more
commonly used as an all-encompassing generic term describing fuel sources
used to provide power.
Energy mix - The combination of sources
used to provide energy at any given time and place. Energy sources include
coal, oil, gas, water (hydro), uranium (nuclear), wind, sunlight,
geothermal, and others.
Entry - An underground horizontal or near-horizontal passage used
for haulage, ventilation, or as a mainway; a coal heading; a working place
where the coal is extracted from the seam in the initial mining; same as
"gate" and "roadway," both British terms.
Evaluation - The work involved in gaining a knowledge of the size,
shape, position and value of coal.
Exploration - The search for mineral deposits and the work done to
prove or establish the extent of a mineral deposit. Alt: Prospecting and
subsequent evaluation.
Explosive - Any rapidly combustive or expanding substance. The
energy released during this rapid combustion or expansion can be used to
break rock.
Extraction - The process of mining and removal of cal or ore from
a mine.
F
Face – The exposed area of a coal bed from which coal is being
extracted.
Face cleat - The principal cleavage plane or joint at right angles
to the stratification of the coal seam.
Face conveyor - Any conveyor used parallel to a working face which
delivers coal into another conveyor or into a car.
Factor of safety - The ratio of the ultimate breaking strength of
the material to the force exerted against it. If a rope will break under a
load of 6000 lbs., and it is carrying a load of 2000 lbs., its factor of
safety is 6000 divided by 2000 which equals 3.
Fall - A mass of roof rock or coal which has fallen in any part of
a mine.
Fan, auxiliary - A small, portable fan used to supplement the
ventilation of an individual working place.
Fan, booster - A large fan installed in the main air current, and
thus in tandem with the main fan.
Fan signal - Automation device designed to give alarm if the main
fan slows down or stops.
Fault - A slip-surface between two portions of the earth's surface
that have moved relative to each other. A fault is a failure surface and is
evidence of severe earth stresses.
Fault zone - A fault, instead of being a single clean fracture,
may be a zone hundreds or thousands of feet wide. The fault zone consists of
numerous interlacing small faults or a confused zone of gouge, breccia, or
mylonite.
Feeder - A machine that feeds coal onto a conveyor belt evenly.
Fill - Any material that is put back in place of the extracted ore
to provide ground support.
Fire damp - The combustible gas, methane, CH4. Also, the explosive
methane-air mixtures with between 5% and 15% methane. A combustible gas
formed in mines by decomposition of coal or other carbonaceous matter, and
that consists chiefly of methane.
Fissure - An extensive crack, break, or fracture in the rocks.
Fixed carbon – The part of the carbon that remains behind when
coal is heated in a closed vessel until all of the volatile matter is driven
off.
Flat-lying - Said of deposits and coal seams with a dip up to 5
degrees.
Flight - The metal strap or crossbar attached to the drag
chain-and-flight conveyor.
Float dust - Fine coal-dust particles carried in suspension by air
currents and eventually deposited in return entries. Dust consisting of
particles of coal that can pass through a No. 200 sieve.
Floor - That part of any underground working upon which a person
walks or upon which haulage equipment travels; simply the bottom or
underlying surface of an underground excavation.
Flue Gas Desulfurization – Any of several forms of
chemical/physical processes that remove sulfur compounds formed during coal
combustion. The devices, commonly called "scrubbers," combine the sulfur in
gaseous emissions with another chemical medium to form inert "sludge" which
must then be removed for disposal.
Fluidized Bed Combustion – A process with a high degree of ability
to remove sulfur from coal during combustion. Crushed coal and limestone are
suspended in the bottom of a boiler by an upward stream of hot air. The coal
is burned in this bubbling, liquid-like (or "fluidized") mixture. Rather
than released as emissions, sulfur from combustion gases combines with the
limestone to form a solid compound recovered with the ash.
Fly ash – The finely divided particles of ash suspended in gases
resulting from the combustion of fuel. Electrostatic precipitators are used
to remove fly ash from the gases prior to the release from a power plant's
smokestack.
Formation – Any assemblage of rocks which have some character in
common, whether of origin, age, or composition. Often, the word is loosely
used to indicate anything that has been formed or brought into its present
shape.
Fossil fuel – Any naturally occurring fuel of an organic nature,
such as coal, crude oil and natural gas.
Fracture - A general term to include any kind of discontinuity in
a body of rock if produced by mechanical failure, whether by shear stress or
tensile stress. Fractures include faults, shears, joints, and planes of
fracture cleavage.
Friable - Easy to break, or crumbling naturally. Descriptive of
certain rocks and minerals.
Fuse - A cord-like substance used in the ignition of explosives.
Black powder is entrained in the cord and, when lit, burns along the cord at
a set rate. A fuse can be safely used to ignite a cap, which is the primer
for an explosive.
G
Gallery - A horizontal or a nearly horizontal underground passage,
either natural or artificial.
Gasification – Any of various processes by which coal is turned
into low, medium, or high Btu gases.
Gathering conveyor; gathering belt - Any conveyor which is used to
gather coal from other conveyors and deliver it either into mine cars or
onto another conveyor. The term is frequently used with belt conveyors
placed in entries where a number of room conveyors deliver coal onto the
belt.
Geologist - One who studies the constitution, structure, and
history of the earth's crust, conducting research into the formation and
dissolution of rock layers, analyzing fossil and mineral content of layers,
and endeavoring to fix historical sequence of development by relating
characteristics to known geological influences (historical geology).
Geotechnical engineering - The branch of
engineering that specializes in assessing the stability and strength of soil
and rock materials, as well as groundwater conditions. With regard to
mining, geotechnical engineering principles are used to determine the
appropriate design of mine features such as pit walls, tunnels, and earthen
embankments.
Gob - The term applied to that part of the mine from which the
coal has been removed and the space more or less filled up with waste. Also,
the loose waste in a mine. Also called goaf.
Global climate change – This term usually refers to the gradual
warming of the earth caused by the greenhouse effect. Many scientists
believe this is the result of man-made emissions of greenhouse gases such as
carbon dioxide, chlorofluorocarbons (CFC) and methane, although there is no
agreement among the scientific community on this controversial issue.
Grain - In petrology, that factor of the texture of a rock
composed of distinct particles or crystals which depends upon their absolute
size.
Greenhouse effect - The natural phenomenon that occurs
when certain atmospheric gases (see greenhouse gases) trap radiated heat in
the atmosphere. The greenhouse effect keeps the atmosphere warm and makes
life on earth possible.
Grizzly - Course screening or scalping device that prevents
oversized bulk material form entering a material transfer system;
constructed of rails, bars, beams, etc.
Ground control - The regulation and final arresting of the closure
of the walls of a mined area. The term generally refers to measures taken to
prevent roof falls or coal bursts.
Ground pressure - The pressure to which a rock formation is
subjected by the weight of the superimposed rock and rock material or by
diastrophic forces created by movements in the rocks forming the earth's
crust. Such pressures may be great enough to cause rocks having a low
compressional strength to deform and be squeezed into and close a borehole
or other underground opening not adequately strengthened by an artificial
support, such as casing or timber.
Gunite - A cement applied by spraying to the roof and sides of a
mine passage.
H
Haulage - The horizontal transport of ore, coal, supplies, and
waste. The vertical transport of the same is called hoisting.
Haulageway - Any underground entry or passageway that is designed
for transport of mined material, personnel, or equipment, usually by the
installation of track or belt conveyor.
Headframe - The structure surmounting the shaft which supports the
hoist rope pulley, and often the hoist itself.
Heading - A vein above a drift. An interior level or airway driven
in a mine. In longwall workings, a narrow passage driven upward from a
gangway in starting a working in order to give a loose end.
Head section - A term used in both belt and chain conveyor work to
designate that portion of the conveyor used for discharging material.
Heaving - Applied to the rising of the bottom after removal of the
coal; a sharp rise in the floor is called a "hogsback".
Highwall – The unexcavated face of exposed overburden and coal in
a surface mine or in a face or bank on the uphill side of a contour mine
excavation.
Highwall miner – A highwall mining system consists of a remotely
controlled continuous miner which extracts coal and conveys it via augers,
belt or chain conveyors to the outside. The cut is typically a rectangular,
horizontal cut from a highwall bench, reaching depths of several hundred
feet or deeper.
Hogsback - A sharp rise in the floor of a seam.
Hoist - A drum on which hoisting rope is wound in the engine
house, as the cage or skip is raised in the hoisting shaft.
Hoisting - The vertical transport coal or material.
hopper - A bin or funnel that is loaded from the top
and which discharges through a door or chute at the bottom.
Horizon - In geology, any given definite position or interval in
the stratigraphic column or the scheme of stratigraphic classification;
generally used in a relative sense.
Horseback - A mass of material with a slippery surface in the
roof; shaped like a horse's back.
Hydraulic - Of or pertaining to fluids in motion. Hydraulic cement
has a composition which permits it to set quickly under water. Hydraulic
jacks lift through the force transmitted to the movable part of the jack by
a liquid. Hydraulic control refers to the mechanical control of various
parts of machines, such as coal cutters, loaders, etc., through the
operation or action of hydraulic cylinders.
Hydrocarbon – A class of compounds containing hydrogen and carbon
formed by the decomposition of plant and animal remains, including coal,
mineral oil, petroleum, natural gas, paraffin, the fossil resins, and the
solid bitumens occurring in rocks. Gasoline is a mixture of hydrocarbons.
I
Inby - In the direction of the working face.
Incline - Any entry to a mine that is not vertical (shaft) or
horizontal (adit). Often incline is reserved for those entries that are too
steep for a belt conveyor (+17 degrees -18 degrees), in which case a hoist
and guide rails are employed. A belt conveyor incline is termed a slope.
Alt: Secondary inclined opening, driven upward to connect levels, sometimes
on the dip of a deposit; also called "inclined shaft".
Incompetent - Applied to strata, a formation, a rock, or a rock
structure not combining sufficient firmness and flexibility to transmit a
thrust and to lift a load by bending.
Indicated coal resources – Coal for which estimates of the rank,
quality, and quantity have been computed partly from sample analyses and
measurements and partly from reasonable geologic projections. The points of
observation are * to 1 * miles apart. Indicated coal is projected to extend
as an * mile wide belt that lies more than * mile from the outcrop or points
of observation or measurement.
Inferred coal resources – Coal in unexplored extensions of the
demonstrated resources for which estimates of the quality and size are based
on geologic evidence and projection. Quantitative estimates are based
largely on broad knowledge of the geologic character of the deposit and for
which there are few, if any, samples or measurements. The estimates are
based on an assumed continuity or repletion of which there is geologic
evidence; this evidence may include comparison with deposits of similar
type. Bodies that are completely concealed may be included if there is
specific geologic evidence of their presence. The points of observation are
1 * to 6 miles apart.
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.
Intake - The passage through which fresh air is drawn or forced
into a mine or to a section of a mine.
Intermediate section - A term used in belt and chain conveyor
network to designate a section of the conveyor frame occupying a position
between the head and foot sections.
Immediate roof - The roof strata immediately above the coalbed,
requiring support during the excavation of coal.
Isopach - A line, on a map, drawn through points of equal
thickness of a designated unit. Synonym for isopachous line; isopachyte.
J
Jackleg - A percussion drill used for drifting or stoping that is
mounted on a telescopic leg which has an extension of about 2.5 m. The leg
and machine are hinged so that the drill need not be in the same direction
as the leg.
Jackrock – A caltrop or other object manufactured with one or more
rounded or sharpened points, which when placed or thrown present at least
one point at such an angle that it is peculiar to and designed for use in
puncturing or damaging vehicle tires. Jackrocks are commonly used during
labor disputes.
Job Safety Analysis (J.S.A.) - A job breakdown that gives a safe,
efficient job procedure.
Joint - A divisional plane or surface that divides a rock and
along which there has been no visible movement parallel to the plane or
surface.
K
Kettle bottom - A smooth, rounded piece of rock, cylindrical in
shape, which may drop out of the roof of a mine without warning. The origin
of this feature is thought to be the remains of the stump of a tree that has
been replaced by sediments so that the original form has been rather well
preserved.
Kerf - The undercut of a coal face.
L
Lamp - The electric cap lamp worn for visibility. Also, the flame
safety lamp used in coal mines to detect methane gas concentrations and
oxygen deficiency.
Layout - The design or pattern of the main roadways and workings.
The proper layout of mine workings is the responsibility of the manager
aided by the planning department.
Lift - The amount of coal obtained from a continuous miner in one
mining cycle.
Lignite - A low-rank coal with a relatively
high moisture content and relatively low heat/energy content.
Liquefaction – The process of converting coal into a synthetic
fuel, similar in nature to crude oil and/or refined products, such as
gasoline.
Lithology - The character of a rock described in terms of its
structure, color, mineral composition, grain size, and arrangement of its
component parts; all those visible features that in the aggregate impart
individuality of the rock. Lithology is the basis of correlation in coal
mines and commonly is reliable over a distance of a few miles.
Load - To place explosives in a drill hole. Also, to transfer
broken material into a haulage device.
Loading machine - Any device for transferring excavated coal into
the haulage equipment.
Loading pocket - Transfer point at a shaft where bulk material is
loaded by bin, hopper, and chute into a skip.
Longwall Mining – One of three major underground coal
mining methods currently in use. Employs a steal plow, or rotation drum,
which is pulled mechanically back and forth across a face of coal that is
usually several hundred feet long. The loosened coal falls onto a conveyor
for removal from the mine.
Loose coal - Coal fragments larger in size than coal dust.
Low Sulphur coal - Coal which has a
sulphur content generally ranging from 0.1 per cent to 1.0 per cent. All
western Canadian coal is low in sulphur.
Low voltage - Up to and including 660 volts by federal standards.
