coal glossary Flashcards
) the weight of the rocks above a narrow roadway is transferred to the
solid coal along the sides, which act as abutments of the arch of strata spanning
the roadway; (2) the weight of the rocks over a longwall face is transferred to the
front abutment, that is, the solid coal ahead of the face and the back abutment, that
is, the settled packs behind the face
Abutment
coal deposits that have been prepared for mining by construction of portals,
shafts, slopes, drifts, and haulage ways; by removal of overburden; or by partial
mining
Accessed
: a mixture of wet and dry deposition (deposited material) from the atmosphere containing higher than typical amount of nitric and
sulfuric acids
Acid deposition or acid rain
the volume of coal that covers 1 acre at a thickness of 1 ft
(43,560 ft3; 1,613.333 yd3; 1,233.482 m3). The weight of coal in this volume
varies according to rank
Acre-foot (acre-ft)
: the volume of coal that covers 1 acre at a thickness of 1 in.
(3,630 ft3; 134.44 yd3; 102.7903 m3). The weight of coal in this volume varies
according to rank.
Acre-inch (acre-in.):
a nearly horizontal passage from the surface by which a mine is entered and
dewatered; a blind horizontal opening into a mountain, with only one entrance
Adit
: mining in the same direction, or order of sequence; first mining as distinguished from retreat.
Advance:
: formation of larger coal or ash particles by smaller particles sticking
together.
Agglomeration:
this angle is assumed to bisect the angle between the vertical and
the angle of repose of the material and is 20∘ for flat seams; for dipping seams,
the angle of break increases, being 35.8∘ from the vertical for a 40∘ dip; the main
break occurs over the seam at an angle from the vertical equal to half the dip.
Angle of draw:
e heaviest distillable coal tar fraction, with distillation range
270–400 ∘C (520–750 ∘F), containing creosote oil, anthracene, phenanthrene,
carbazole, and so on
Anthracene oil
US Bureau of Mines term for vitrinite viewed by transmitted light.
Anthraxylon
constituents of interest are silica (SiO2) alumina (Al2O3), titania (TiO2), ferric oxide (Fe2O3), lime (CaO), magnesia (MgO), potassium oxide
(K2O), sodium oxide (Na2O), and sulfur trioxide (SO3)
ash constituents
the moisture present in a coal sample when delivered.
As-received moisture
represents an analysis of a sample as received at a laboratory.
As-received basis
a microscopic coal constituent composed of macerated plant debris
intimately mixed with mineral matter and coalified. US Bureau of Mines usage,
viewed by transmitted light.
Attritus
the roof or upper part in any underground mining cavity
Back
operation of refilling an excavation. Moreover, the material placed in an
excavation in the process of
Backfill
an air pollution control device that removes particulate matter from flue
gas, usually achieving a removal rate above 99.9%.
Baghouse:
: liquid volume measure equal to 42 US gals, commonly used in measuring
petroleum or petroleum products.
Barrel:
enclosing part of a mine to prevent inflow of noxious gasses from a
mine fire or an explosion
Barricading
a bar or straight girder used to support a span of roof between two support
props or walls.
Beam
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
a dome-shaped oven not equipped to recover the by-product gas and
liquids evolved during the coking process.
Beehive oven
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 conveyor
a crawler-mounted surge bin often equipped with a
crusher or breaker and used in room-and-pillar sections positioned at the end of the section conveyor belt. It allows a quick discharge of the shuttle car. It sizes the
coal and a built-in conveyor feeds it at an appropriate rate onto the conveyor belt.
Belt Feeder (Feeder breaker):
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 idler
treatment of mined material, making it more concentrated or
richer
Beneficiation
a streak of impurity in a coal seam
Binder:
high in carbonaceous matter, having less than 86% fixed carbon, and
more than 14% volatile matter on a dry, mineral-matter-free basis and more
than 10,500 Btu on a moist, mineral-matter-free basis. This class may be either
agglomerating or non-agglomerating and is divisible into the high-volatile C, B,
A; medium; and low volatile bituminous coal groups on the basis of increasing
heat content and fixed carbon and decreasing volatile matter
Bituminous (soft) coal
a deadly gas that is caused from coal burning in an atmosphere which
lacks oxygen; mostly a mixture of carbon dioxide and nitrogen found in mines
after fires and explosions.
Blackdamp
a respiratory disease caused by prolonged inhalation of
coal dust
Black lung (anthracosis)
va detonator containing a charge of detonating compound, which is
ignited by electric current or the spark of a fuse. Used for detonating explosives
Blasting cap
: a mixture consisting chiefly of carbon monoxide and hydrogen formed by
action of steam on hot coal or coke
Blue gas
same as cannel coal except that algal remains can be seen under the
microscope.
Boghead coal
: a molten ash collected at the base of slag tap and cyclone boilers that
is quenched with water and shatters into black, angular particles having a smooth
glassy appearance.
Boiler slag
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
Brattice or brattice cloth:
passage for ventilation that is cut through the pillars between
rooms.
Breakthrough
a rubber-tire-mounted mobile conveyor, about 10 m long, used as
an intermediate unit to create a system of articulated conveyors between a mining
machine and a room or entry conveyor.
Bridge carrier
US Bureau of Mines term for a combination of clarain and vitrain with
small amounts of fusain
Bright coal
a process of applying pressure to coal fines, with or without a binder,
to form a compact or agglomerate
Briquetting
the quantity of heat required to raise the temperature of
one pound of water one ∘F at, or near, its point of maximum density of 39.1 ∘F
(equivalent to 251.995 g calories; 1,054.35 J; 1.05435 kJ; 0.25199 kcal).
British thermal unit (Btu)
a low place in the roof of a mine, giving insufficient headroom.
Brow:
the fine particles of coal or other material resulting from the boring or
cutting of the coal face by drill or machine
Bug dust
: digging up the bottom or taking down the top to give more headroom in
roadways
Brushing
violent dislocation of the mine workings which is attributed to
severe stresses in the rock surrounding the workings
Bump (or burst)
a short, poorly defined vertical cleavage plane in a coal seam, usually at
right angles to the long face cleat
Butt cleat
e quantity of heat required to raise 1 g of water from 15 to 16 ∘C; a calorie
is also termed gram calorie or small calorie (equivalent to 0.00396832 Btu; 4.184 J;
0.001 kg calorie).
Calorie:
the quantity of heat that can be liberated from one pound of coal or
oil measured in Btu/lb.
Calorific value
predominately durain with lesser amounts of vitrain than splint coal
and small quantities of fusain. Spores can be seen under the microscope.
Cannel coal
a flat piece of wood inserted between the top of the prop and the roof to
provide bearing support
Cap block
: a process whereby coal is converted to coke by devolatilization.
Carbonization
: a directed throw; in strip-mining, the overburden is cast from the coal to the
previously mined area
Cast
a conveyor on which the material is moved along solid pans
(troughs) by the action of scraper crossbars attached to powered chains
Chain conveyor
the pillar of coal left to protect the gangway or entry and the parallel
airways.
Chain pillar
large hydraulic jacks used to support roof in longwall and shortwall mining
systems
Chock
a macroscopic coal constituent (lithotype) known as bright-banded coal,
composed of alternating bands of vitrain and durain
Clarain
: a fissure that has been infilled as a result of gravity, downward-percolating
ground waters, or compactional pressures which cause unconsolidated clays or
thixotropic sand to flow into the fissure
Clay vein
natural opening-mode fractures in coal beds which account for most of the
permeability and much of the porosity of coalbed gas reservoirs
Cleats:
particles of coal that can pass a No. 20 sieve.
Coal dust
: strata containing one or more coal beds.
Coal measures
a recombined coalbed sample produced by averaging together
thickness-weighted coal analyses from partial samples of the coalbed, such as from
one or more bench samples, from one or more mine exposures or outcrops where
the entire bed could not be accessed in one sample, or from multiple drill cores
that were required to retrieve all local sections of a coal seam.
Composite sample
Any
partings greater than 3/8 in. and/or mineral concretions greater than 1/2 in. thick
and 2 in. in maximum diameter are normally discarded from a channel sample so as better to represent coal that has been mined, crushed, and screened to remove
at least gross non-coal materials.
Face channel or channel sample
the condensable distillate containing light, middle, and heavy oils obtained
by carbonization of coal. About 8 gal of tar is obtained from each ton of bituminous
coal
Coal tar:
also refer to gasification and liquefaction processes in which the coal is upgraded to a gaseous or
liquid product
refined coal
: a series of laterally extensive and (or) lenticular coal beds and associated
strata that arbitrarily can be viewed as a unit; generally, the coal beds in a coal
zone are assigned to the same geologic member or formation
Coal zone
coal pieces larger than 1/2 mm in size
Coarse coal
a process by which electricity and steam, for space heating or
industrial-process heating, are produced simultaneously from the same fuel.
Cogeneration
a gray, hard, porous, and coherent cellular-structured combustible solid, primarily composed of amorphous carbon; produced by destructive distillation or
thermal decomposition of certain bituminous coal that passes through a plastic
state in the absence of air.
Coke:
British name for coal mine
Colliery:
: breaking, crushing, or grinding of coal, ore, or rock.
Comminution
a coal or a blend of coals that meets sulfur dioxide emission standards for air quality without the need for flue gas desulfurization
Compliance coal
a volume of sedimentary rock in which mineral cement fills the spaces
between the sediment grains; often ovoid or spherical in shape, although irregular
shapes also occur
Concretion
a mechanical mining machine consisting of a cutting head,
a coal-gathering device, a chain conveyor with flexible loading boom, and a
crawler-equipped chassis. Its function is to excavate the mineral and to load it
onto shuttle cars or continuous-haulage systems. It is electrically powered, with a
hydraulic subsystem for auxiliary functions. Power is supplied through a trailing
cable
Continuous miner:
the removal of overburden and mining from
a coal seam that outcrops or approaches the surface at approximately the same
elevation in steep or mountainous areas
Contour mining (contour stripping)
: 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 and is also may be called a chock or
cog.
Crib
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
Cribbing
coal at the outcrop of the seam; usually considered to be of inferior quality
due to partial oxidation, but this is not always the case.
Crop coal:
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
Crosscut
an entry running at an angle with the main entry
Cross entry
a machine, usually used in coal, that will cut a 10–to
15-cm slot which 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
Cutter, Cutting machine
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.
Cycle mining
: a cone-shaped air-cleaning apparatus which operates by centrifugal separation that is used in particle collecting and fine grinding operation
Cyclone
an equipment in which centrifugal force is used to separate particulates from a gas stream
Cyclone collectors
refers to slagging combustion of coarsely pulverized coal in a cylindrical (cyclone) burner. Some wet-bottom boilers are not cyclone-fired. The primary by-product is a glassy slag referred to as boiler sl
Cyclone firing
a collective term for the sum of coal in both measured and
indicated resources and reserves.
Demonstrated reserves
a dense slurry formed by the suspension of heavy particles in water;
used to clean coal
Dense medium
gravity downflow of packed solids contacted with
upwardly flowing gases—sometimes referred to as fixed-bed or moving-bed
system
Descending-bed system:
work undertaken to open up coal reserves as distinguished
from the work of actual coal extraction
Development mining
the removal of vaporizable material by the action of heat
Devolatilization
: blending of a gas and air, resulting in a homogeneous mixture; blending
of two or more gases
Diffusion:
: 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.
Dilute:
fan mounted on a continuous miner to assist and direct air delivery
from the machine to the face
Diffuser fan
: hydrogenation of coal without use of a separate donor solvent
hydrogenation step.
Direct hydrogenation
the contamination of ore with barren wall rock in stopping.
Dilution
air forced down into the mine below, by way of the airshaft which is
adjacent to the escape shaft.
Downcast:
the process of removing surplus ground or surface water either by artificial
means or by gravity flow.
Drainage
a soft slate, shale, or rock from approximately 1–10 cm thick and located
immediately above certain coal seams, which falls quite easily when the coal support is withdraw
Draw slate
t follows the vein, as distinguished
from a crosscut that intersects it, or a level or gallery, which may do either. horizontal passage underground
Drift
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.
Drift mine
; if the hole is much over 0.4 m in diameter, the machine is called
borer.
a coal analysis basis calculated as if moisture and ash were
removed
Dry, ash-free (daf) basis
a bag filled with sand, clay, etc., used for stemming a charged hole
Dummy
a system similar to a fluidized bed but operated at higher
gas velocities, such that a portion of the solids is carried out with the up-flowing
gas.
Ebullating-bed reactor
: a process in which heat is absorbed
Endothermic reaction
the moisture capacity of coal at 30 ∘C (86 ∘F) in an atmosphere of 95% relative humidity
Equilibrium moisture
: a microscopic coal constituent (maceral) or maceral group containing spores
and cuticles. Appears dark gray in reflected light.
Exinite:
a process in which heat is evolved.
Exothermic reaction
the solid unbroken surface of a coal bed that is at the advancing end of the mine
workplace
Face
: the principal cleavage plane or joint at right angles to the stratification of
the coal seam
Face cleat
a conveyor used on longwall mining faces and consisting of a metal
trough with an integrated return channel. Steel scrapers attached to an endless
round link or roller-type chain force through the trough any material deposited
inside the trough by the mining machine. Spill plates and guides for mining equipment are attached. For flexibility and ease of installation the conveyor is made up
of 5-ft sections. Commonly, two electrically powered drives (one on each end)
move chain, scrapers (flights), and material along
Face conveyor
hydraulically powered units used to support the roof along a longwall
face. They consist of plates at the roof and floor and 2–6 hydraulic cylinders that
press these plates against the respective surfaces with forces of 200–800 tons
Face supports
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 lb, and it is
carrying a load of 2000 lb, its factor of safety is 3 (6000 divided 2000).
Factor of safety:
a small, portable fan used to supplement the ventilation of an individual working place.
Fan, auxiliary
an automation device designed to give alarm if the main fan slows down
or stops
Fan signal:
unburned coal, ash, and spent bed material used for sulfur control.
The spent bed material (removed as bottom ash) contains reaction products from
the absorption of gaseous sulfur oxides (SO2 and SO3)
FBC materials
derived from a variety of processes used to control sulfur emissions from boiler stacks. These systems include wet scrubbers, spray dry scrubbers, sorbent injectors, and a combined sulfur oxide (SOx) and nitrogen oxide
(NOx) process. Sorbents include lime, limestone, sodium-based compounds, and
high-calcium coal fly ash.
FGD materials
typically any material that is put back in place of the extracted coal—sometimes
to provide ground support.
Fill
: coal pieces less than 1/2 mm in size
Fine coal
the content of fine particles, usually less than c in., in a coal sample
Fines
an explosive mixture of carbonaceous gases, mainly methane, formed in
coal mines by the decomposition of coal
Firedamp
the combustible residue left after the volatile matter is driven off. In
general, the fixed carbon represents that portion of the fuel that must be burned in
the solid state.
Fixed carbon
: separation of crushed coal into density fractions using a
series of heavy liquids. Each fraction is weighed and analyzed for ash and often
for sulfur content. Washability curves are prepared from these data
Float-and-sink analysis
water-soluble or colloidal chemical reagents that when added to finely
dispersed suspensions of solids in water, promote the formation of flocs of the
particles and their rapid settlement
Flocculants:
: the removal of sulfur oxides
Flue gas desulfurization (FGD or scrubbing)
removal of the sulfur gases from the flue gases
(stack gases) of a coal-fired boiler—typically using a high-calcium sorbent such
as lime or limestone. The three primary types of FGD processes commonly used
by utilities are wet scrubbers, dry scrubbers, and sorbent injection
Flue gas desulfurization (FGD)
the degree of plasticity exhibited by a sample of coal heated in the absence
of air under controlled conditions, as described in ASTM Standard Test Methods
D1812 and D2639.
Fluidity
accomplishes coal combustion by mixing the
coal with a sorbent such as limestone or other bed material. The fuel and bed
material mixture is fluidized during the combustion process to allow complete
combustion and removal of sulfur gases. Atmospheric FBC (AFBC) systems
may be bubbling (BFBC) or circulating (CFBC). Pressurized FBC (PFBC) is an
emerging coal combustion technology.
Fluidized-bed combustion (FBC):
solids suspended in space by an upwardly moving gas stream.
Fluidized-bed system
the temperature at which the coal ash
becomes fluid and flows in streams
Fluid temperature (ash fluid temperature)
airborne bits of unburnable ash that are carried into the atmosphere by stack
gases; coal ash that exits a combustion chamber in the flue gas and is captured by
air pollution control equipment such as electrostatic precipitators, baghouses, and
wet scrubbers
Fly ash
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 shap
Formation
the accumulation of small, sticky molten particles of coal ash on a boiler
surface
Fouling
the part of coal moisture that is removed by
air-drying under standard conditions approximating atmospheric equilibrium.
Free moisture (surface moisture):
a measure of the agglomerating tendency of coal heated to
800 ∘C (1470 ∘F) in a crucible. Coals with a high index are referred to as coking
coals; those with a low index are referred to as free-burning coal
Free swelling index:
the tendency of coal particles to break down in size during storage, transportation, or handling; quantitatively expressed as the ratio of average particle size
after test to average particle size before test, times 100.
Friability
a process for cleaning coal fines in which separation from mineral
matter is achieved by attachment of the coal to air bubbles in a water medium,
allowing the coal to gather in the froth while the mineral matter sinks.
Froth flotation
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
Fuse
a microscopic coal constituent (maceral) with well-preserved cell structure
and cell cavities empty or occupied by mineral matter
Fusinite
a horizontal or a nearly horizontal underground passage, either natural or
artificial
Gallery
method of utilizing coal by
burning in place and extracting the released gases, tars, and heat
Gasification, underground (in situ gasification)
: gas treatment to remove contaminants such as fly ash, tars, oils,
ammonia, and hydrogen sulfide.
Gas purification:
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
which is also called goaf
Gob
in the coal industry, the term 5 in. to 3/4 in. means all coal pieces between
5 in. and 3/4 in. at their widest point. Plus 5 in. means coal pieces over 5 in. in size;
11/2 in. to 0 or −11/2 in. means coal pieces 11/2 in. and under
Goal sizes
a term indicating the nature of coal as mainly determined by the sulfur content and the amount and type of ash; not recommended for use in coal resource
estimations; definitive statements as to the contents and types of sulfur and ash are preferable—statements indicating high, medium, or low grade are inappropriate
without documentation
Grade
an equipment that uses a bed of a separate, closely packed
solids as the separation medium.
Granular bed filters
the treatment of coal particles that depends mainly on differences in specific gravity of particles for separation
Gravity separation:
a number that indicates the ease of pulverizing a coal in comparison to a reference coal. This index is helpful in estimating mill capacity. The two
most common methods for determining this index are the Hardgrove Grindability Method and Ball Mill Grindability Method. Coals with a low index are more
difficult to pulverize
Grindability index:
a course screening or a scalping device that prevents oversized bulk material
from entering a material transfer system; constructed of rails, bars, beams
Grizzly
: 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 control:
: a cement applied by spraying to the roof and sides of a mine passage.
Gunite
coal with a heat content greater than 10,260 Btu/lb. on a moist ash-free
basis. Includes anthracite, bituminous, and the higher-rank subbituminous coals.
Hard coal:
the weight percent of coal retained on a No. 200
sieve after treatment as specified in ASTM Standard Test Method D409
Hardgrove grindability index
the horizontal transport of ore, coal, supplies, and waste; the vertical transport of the same is called hoisting.
Haulage
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
Haulageway
he structure surmounting the shaft which supports the hoist rope pulley,
and often the hoist itself.
Headframe
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.
Heading:
a term used in both belt and chain conveyor work to designate that
portion of the conveyor used for discharging material.
Head section:
the amount of heat obtainable from coal expressed
in British thermal units per pound, joules per kilogram, kilojoules or kilocalories
per kilogram, or calories per gram: to convert Btu/lb to kcal/kg, divide by 1.8. To
convert kcal/kg to Btu/lb, multiply by 1.8.
Heat of combustion, heat value
: applied to the rising of the bottom after removal of the coal; a sharp rise in
the floor is called a hogsback
Heaving
: a heavy coal tar fraction with distillation range usually 250–300 ∘C
(480–570 ∘F), containing naphthalene and coal tar bases
Heavy oil:
the heavy distillate from the pyrolysis of coal at a temperature of about 800 ∘C (1470 ∘F).
High temperature tar
three related rank groups of bituminous coal as
defined by the American Society for Testing and Materials which collectively
contain less than 69% fixed carbon on a dry, mineral-matter-free basis; more than
31% volatile matter on a dry, mineral-matter-free basis; and a heat value of more
than 10,500 Btu per pound on a moist, mineral-matter-free basis.
High-volatile bituminous coal
the unexcavated face of exposed overburden and coal in a surface mine or
the face or bank on the uphill side of a contour strip mine excavation
Highwall
: 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.
Highwall mining
a sharp rise in the floor of a seam
Hogsback
: a drum on which hoisting rope is wound in the engine house, as the cage or
skip is raised in the hoisting shaft
Hoist
: the vertical transport coal or material
Hoisting:
a mass of material with a slippery surface in the roof; shaped like a
horse’s back.
Horseback
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
Hydraulic
hydraulic device for separating suspended solid particles from liquids by centrifugal action. Cyclone action splits the inlet flow, a small part of
which exits via the lower cone, the remainder overflowing the top of the cylindrical section. Particles are separated according to their densities, so that the denser
particles exit via the cone underflow and less dense particles exit with the overflo
Hydrocyclone
reaction of carbonaceous material such as coal with hydrogen to
produce methane.
Hydrogasification:
chemical reaction in which hydrogen is added to a substance
Hydrogenation
coal having 25 wt% or more, but less than 50 wt% ash on the dry basis
(ASTM, 1981; D-2796, p. 344); impure coal having more than 33 weight percent
ash is excluded from resource and reserve estimates unless the coal is cleanable to
less than 33 wt% ash
Impure coal
in the direction of the working face
Inby
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∘ −18∘), 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.
Incline: a
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.
Incompetent
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 1/2 to 11/2 miles
apart. Indicated coal is projected to extend as an 1/2 mile wide belt that lies more
than 1/4 mile from the outcrop or points of observation or measurement
Indicated coal resources
coal is first gasified to make a synthesis gas. The gas is then
passed over a catalyst to produce methanol or paraffinic hydrocarbons.
Indirect hydrogenation
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 1/2 to 6 miles apart.
Inferred coal resources:
the term inferred reserves is commonly
used in addition to, or in place of, potential reserves.
Inferred reserves (unproved reserves):
the temperature at which coal begins to fuse and become soft
Initial deformation temperature (ash initial deformation temperature)
the passage through which fresh air is drawn or forced into a mine or to a
section of a mine.
Intake:
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
Intermediate section
the roof strata immediately above the coalbed, requiring support
during the excavation of coal.
Immediate roof:
a line, on a map, drawn through points of equal thickness of a designated
unit. Synonym for isopachous line; isopachyte
Isopach
a percussion drill used for drifting or stopping 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
Jackleg
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.
Jackrock:
machines that produce stratification of the particles in a bed or particles of differing densities by repeated differential agitation of the bed, the heaviest particles
migrating to the lowest layer. The jigging action may be carried out in air or with
the bed immersed in water or other liquids
Jigs
a job breakdown that gives a safe, efficient job procedure.
Job Safety Analysis (JSA):
: 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
Kettle bottom
the undercut of a coal face
Kerf
the electric cap lamp worn for visibility; also, the flame safety lamp used in
coal mines to detect methane gas concentrations and oxygen deficiency.
Lamp
the amount of coal obtained from a continuous miner in one mining cycle
Lift
a coal tar and coal gas fraction with distillation range between 80 and
210 ∘C (175–410 ∘F) containing mainly benzene with smaller amounts of toluene
and xylene
Light oil
; a class of brownish-black, low-rank
coal defined by the American Society for Testing and Materials as having less
than 8300 Btu on a moist, mineral-matter-free basis; in the United States, lignite
is separated into two groups: Lignite A (6300–8300 Btu) and lignite B (<6300
Btu)
Lignite
the conversion of coal into nearly mineral-free hydrocarbon liquids or
low-melting solids by a process of direct or indirect hydrogenation at elevated temperatures and pressures and separation of liquid products from residue by either
filtration or distillation or both
Liquefaction
a mixture of propane and butane
Liquefied petroleum gas (LPG)
coal lithotypes represent the macrostructure of coal and are, in fact,
descriptive of the coal.
Lithotypes
to place explosives in a drill hole; also, to transfer broken material into a
haulage device
Load
a mining method in which a large rectangular section of coal is
removed in one continuous operation. Equipment is installed along one side of
the section (the longwall face) and the coal is removed in slices 2–4 ft thick. The
excavated area behind the equipment is allowed to cave
Longwall mining
: coal fragments larger in size than coal dust.
Loose coal
a nitrogen-rich gas with a heat content of 100–200 Btu/ft3 produced
in gasification processes using air as the oxygen source. The air-blown form of
producer gas.
Low-Btu gas
up to and including 660 V by federal standards
Low voltage
microscopic petrographic units of coal.
Maceral
a safety hole constructed in the side of a gangway, tunnel, or slope in which
miner can be safe from passing locomotives and car. This is also called a refuge
hole.
Manhole
a carrier of mine personnel, by rail or rubber tire, to and from the work
area
Man trip
coal for which estimates of the rank, quality, and quantity
have been computed from sample analyses and measurements from closely spaced
and geologically well-known sample sites, such as outcrops, trenches, mine workings, and drill holes. The points of observation and measurement are so closely
spaced and the thickness and extent of coals are so well defined that the tonnage
is judged to be accurate within 20% of true tonnage. Although the spacing of the
points of observation necessary to demonstrate continuity of the coal differs from
region to region according to the character of the coal beds, the points of observation are no greater than 1/2 mile apart. Measured coal is projected to extend as a
1/4-mile wide belt from the outcrop or points of observation or measurement.
Measured coal resources
a surveying term that establishes a line of reference. The bearing is used to
designate direction. The bearing of a line is the acute horizontal angle between the
meridian and the line. Azimuths are angles measured clockwise from any meridian.
Meridian:
coal used in the steelmaking process to manufacture coke; metallurgical coal; an informally recognized name for bituminous coal that is suitable
for making coke by industries that refine, smelt, and work with iron—other uses
are space heating, blacksmithing, smelting of base metals, and power generation;
generally, metallurgical coal has less than 1% sulfur and less than 8% ash on an
as-received basis—most premium metallurgical coal is low- to medium-volatile
bituminous coal
Metallurgical coal
potentially explosive gas formed naturally from the decay of vegetative matter, similar to that which formed coal. Methane, which is the principal
component of natural gas, is frequently encountered in underground coal mining operations and is kept within safe limits through the use of extensive mine
ventilation systems
Methane
the microscopic analogs of the coal lithotypes and, hence, represent
a part of the fine microstructure of coal; associations of coal macerals with the
proviso that the associationsshould occur within an arbitrary minimum bandwidth
(50 μ, 50 × 10 mm)
Microlithotypes
coal of an intermediate specific gravity and quality
Middlings:
: a process for catalytic conversion of 1 mole of carbon monoxide and
3 moles of hydrogen to 1 mole of methane and 1 mole of water
Methanation:
a coal tar fraction with a distillation range of
200–270 ∘C (390–520 ∘F), containing mainly naphthalene, phenol, and cresols.
Middle (carbolic or creosote) oil
land with new surface characteristics due to the removal of minable
commodities by surface-mining methods and subsequent surface reclamation.
Mined land
a coal burning electric-generating plant built near a coal
mine.
Mine mouth electric plant
a reaction system in which coal and air or oxygen with steam
are contacted underneath a pool of liquid iron, ash, or salt
Molten bath gasifier
a form of surface mining in which
the summit or summit ridge of a mountain is removed in order to permit easier
access to coal seams; after the coal is extracted, the overburden is either put back
onto the ridge to approximate the original contours of the mountain or dumped
elsewhere, often in neighboring valleys; generally associated with coal mining in
the Appalachian Mountain areas
Mountain top removal (mountaintop removal)
a charge of high explosive fired in contact with the surface of a rock after
being covered with a quantity of wet mud, wet earth, or sand, without any borehole
being used. This is also termed adobe, dobie, and sandblast (illegal in coal mining)
Mud cap
mining in areas where several seams are recovered from the
same area
Multiple-seam mining
a naturally occurring gas with a heat content over 1000 Btu/ft3, consisting mainly of methane but also containing smaller amounts of the C2–C4 hydrocarbons as well as nitrogen, carbon dioxide, and hydrogen sulfide
Natural gas:
a device at the end of the trailing cable of a mining machine used for connecting
the trailing cable to the trolley wire and ground.
Nip
treatment of a suspension of fine coal particles suspended in
water with a light hydrocarbon oil so that the particles are preferentially collected
by the oil, which separates as a floating pasty agglomerate and can be removed by
skimming. First developed as a method for recovering fine coal particles by Trent
in 1914
Oil agglomeration
a method of mining pillars in which no stump is left; the pockets
driven are open on the gob side and the roof is supported by timber
Open end pillaring:
a distance nearer to the shaft and hence farther from the working
face, toward the mine entrance, and the opposite of inby
Outby; outbye:
enclosed airway which permits one air current to pass over
(under) another without interruption
Overcast (undercast):
bituminous coal, the properties of which have been fundamentally
modified as a result of chemisorption of oxygen in the air or oxygen dissolved
in groundwater. The chemisorption is a surface phenomenon rarely detectable by
chemical analysis but usually detectable by petrographic examination. It reduces
the affinity of coal surfaces for oil and seriously impairs coking, caking, and agglutinating properties
Oxidized coal
a coal mining block that generally comprises one operating unit
Panel
: a switch, in the shape of a bar, used to cut off power at the machine in
case of an emergency.
Panic bar
a layer or stratum of non-coal material in a coal bed which does not exceed
the thickness of coal in either the directly underlying or overlying benches.
Parting
he proportion of a coal seam which is removed from the
mine. The remainder may represent coal in pillars or coal which is too thin or
inferior to mine or lost in mining. Shallow coal mines working under townships,
reservoirs, etc., may extract 50%, or less, of the entire seam, the remainder being
left as pillars to protect the surface. Under favorable conditions, longwall mining may extract from 80% to 95% of the entire seam. With pillar methods of working,
the extraction ranges from 50% to 90% depending on local conditions.
Percentage extraction
a drill, usually air powered, that delivers its energy through a
pounding or hammering action.
Percussion drill
that which is allowable or permitted. It is most widely applied to mine
equipment and explosives of all kinds that are similar in all respects to samples that
have passed certain tests of the MSHA and can be used with safety in accordance
with specified conditions where hazards from explosive gas or coal dust exist.
Permissible:
a branch of coal petrology specifically deals with the analysis of the
maceral composition and rank of coal and therefore plays an essential role in predicting coal behavio
Petrography
the study of the organic and inorganic constituents of coal and their transformation via metamorphism.
Petrology
a processes that employ a number of different operations,
including crushing, sizing, dewatering and clarifying, and drying, which improve
the quality of the fuel by regulating its size and reducing the quantities of ash,
sulfur, and other impurities. In this text, the term coal cleaning is synonymous
with the terms coal preparation, beneficiation, and washing.
Physical coal cleaning:
a bridge conveyor.
Piggy-back
an area of coal left to support the overlying strata in a mine; sometimes left
permanently to support surface structures
Pillar
he systematic removal of the coal pillars between rooms or chambers to regulate the subsidence of the roof; also termed bridging back the pillar,
drawing the pillar, or pulling the pillar.
Pillar robbing:
: a compression of the walls of a vein or the roof and floor of a coal seam so as
to squeeze out the coal.
Pinch
a methane-rich gas with a heat content of 950–1050 Btu/ft3
compressed to 1000 psi
Pipeline gas
used in reference to a specifically describable area of open-cut mining. May be
used to refer to only that part of the open-cut mining area from which coal is being
actively removed or may refer to the entire contiguous mined area; also used in
Britain to refer to a mine
Pit
a small railroad-type car approximately 6 × 3 in size, used to haul coal, dirt
and rock
Pit Car
the inclination of a seam; the rise of a seam; also, the nonvolatile portion of
coal tar.
Pitch:
a property of certain coals when heated in the absence of air. For a relative
and a semiquantitative method for determining the relative plastic behavior of coal,
refer to ASTM Standard Test Methods D2639 and D1812, respectively
Plasticity
a chronic disease of the lung arising from breathing coal dust.
Pneumoconiosis:
a large machine for digging, the digging part of which is a bucket
as the terminal member of an articulated boom. Power to the bucket is supplied
through hydraulic cylinders or cables.
Power shovel
a measure of the maximum random error or deviation of a single observation. It may be expressed as the standard error or a multiple thereof, depending
on the probability level desired
Precision
the heating of coal in a preheating column to
180–300 ∘C (355–570 ∘F) to dry off all the moisture and leave a hot, dry fluid
coal that can be charged by gravity or pipeline
Preheating (coke making):
mild oxidation of coal to eliminate caking (agglomeration) tendencies.
Pretreatment
a package or cartridge of explosive which is designed specifically
to transmit detonation to other explosives and which does not contain a detonator.
Primer (booster)
: mainly carbon monoxide with smaller amounts of hydrogen, methane,
and variable nitrogen, obtained from partial combustion of coal or coke in air or
oxygen, having a heat content of 110–160 Btu/ft3 (air combustion) or 400–500
Btu/ft3 (oxygen combustion)
Producer gas
the determination by prescribed methods of moisture, volatile
matter, fixed carbon (by difference), and ash; unless specified, proximate analyses do not include determinations of sulfur or phosphorous or any determinations other
than those named; proximate analyses are reported by percent and on as-received,
moisture-free, and moisture- and ash-free bases. Pulverized coal combustion refers
to any combustion process that uses very finely ground (pulverized) coal in the
process
Proximate analysis:
a secondary or tertiary inclined opening, vertical or near-vertical opening
driven upward form a level to connect with the level above, or to explore the ground
for a limited distance above one level
Raise:
a secondary or tertiary inclined opening, driven to connect levels, usually
driven in a downward direction, and used for haulage.
Ramp: a
run-of-mine coal that has been treated by the removal of tramp material,
screening, or crushing.
Raw coal:
: the process of reconverting mined land to its former or other productive
uses.
Reclamation
unmined coal deposits that can be removed by current
technology, taking into account economic, legal, political and social variables.
Recoverable reserves (coal)
a nonvolatile combustion product of the oxidation of coal or coal refuse.
Most commonly applied to material resulting from in situ, uncontrolled burning
of coal or coal refuse piles. It is similar to coal ash
Red dog
: the ratio between the feed top size and the product top size; the
ratio between the feed and product sizes
Reduction ratio
the measure of agreement between test results carried out by more
than one person with more than one instrument in more than one laboratory.
Reproducibility
closeness of agreement between test results carried out by one
person with one instrument in one laboratory
Repeatability
that portion of the identified coal resource that can be economically mined
at the time of determination. The reserve is derived by applying a recovery factor
to that component of the identified coal resource designated as the reserve base
that portion of the identified coal resource that can be economically mined
at the time of determination. The reserve is derived by applying a recovery factor
to that component of the identified coal resource designated as the reserve base
a method of permanent roof support in which steel rods are grouted
with resin.
Resin bolting
dust particles 5 𝜇 or less in size
Respirable dust
a sample collected with an approved coal mine dust sampler unit attached to a miner, or so positioned as to measure the concentration of
respirable dust to which the miner is exposed, and operated continuously over an
entire work shift of such miner
Respirable dust sample
a system of robbing pillars in which the robbing line, or line through
the faces of the pillars being extracted, retreats from the boundary toward the shaft
or mine mouth.
Retreat mining
the idler or roller underneath the cover or cover plates on which the
conveyor belt rides after the load which it was carrying has been dumped at the
head section and starts the return trip toward the foot section.
Return idler
the side of a pillar or the wall of an entry. The solid coal on the side of any
underground passage. Same as rib pillar.
Rib: t
a thin seam of coal overlying a thicker one.
Rider:
a coal extraction machine that works by tearing the coal from the face.
Ripper
to extract pillars of coal previously left for support
Rob:
that part of a mine from which the pillars have been removed
Robbed out area
) a high place in the bottom or a low place in the top of a mine passage, (2) a
local thickening of roof or floor strata, causing thinning of a coal seam.
Roll: (
a framework, safety canopy, or similar protection for the operator
when equipment overturns
Roll protection
: a long steel bolt driven into the roof of underground excavations to support
the roof, preventing and limiting the extent of roof falls. The unit consists of the
bolt (up to 4 ft long), steel plate, expansion shell, and pal nut. The use of roof
bolts eliminates the need for timbering by fastening together, or laminating, several
weaker layers of roof strata to build a beam.
Roof bolt
a coal mine cave-in especially in permanent areas such as entries.
Roof fall
a screw- or pump-type hydraulic extension post made of steel and used
as temporary roof support.
Roof jack
the sinking, bending, or curving of the roof, especially in the middle, from
weight or pressure.
Roof sag
unbalanced internal forces in the roof or sides, created when coal is
extracted
Roof stress
: posts, jacks, roof bolts and beams used to support the rock overlying
a coal seam in an underground mine. A good roof support plan is part of mine
safety and coal extraction
Roof support:
a combination of steel rods anchored into the roof to create zones of
compression and tension forces and provide better support for weak roof and roof
over wide areas
Roof trusses
a mining method in which a designated area is divided
into regular-shaped coal pillars through the parallel development of entries and
cross-cuts. After the area is so developed, the remaining pillars are mined by slicing them into smaller pillars
Room-and-pillar mining:
the short passage from the entry into a room
Room neck
: planned pattern of drill holes fired in sequence in tunneling, shaft sinking,
or stopping. First the cut holes are fired, followed by relief, lifter, and rib holes.
Round
he total area (top, bottom, and sides) of an airway
Rubbing surface
: raw coal as it leaves the mine prior to any type of crushing or
preparation
Run-of-mine coal:
: a train of powder enclosed in cotton, jute yarn, or waterproofing compounds, which burns at a uniform rate; used for firing a cap containing the detonation compound which in turn sets off the explosive charge.
Safety fuse
a lamp with steel wire gauze covering every opening from the inside to
the outside so as to prevent the passage of flame should explosive gas be encountered
Safety lamp
a large unmined area left between a mining section and mine openings
designated for long-term use. It is laid out to absorb the abutment loads created by the mining activity and to prevent any adverse effects on the openings designated
for long-term use.
Safety pillar
any of several forms of chemical/physical devices that remove sulfur
compounds formed during coal combustion. These devices, technically known as
flue gas desulfurization systems, combine the sulfur in gaseous emissions with
another chemical medium to form inert sludge, which must then be removed for
disposa
Scrubbers
the object of selective mining is to obtain a relatively high-grade
mine product; this usually entails the use of a much more expensive stopping system and high exploration and development costs in searching for and developing
the separate bunches, stringers, lenses, and bands of ore.
Selective mining
a self-contained supply of oxygen used during
rescue work from coal mine fires and explosions; same as SCSR (self-contained
self-rescuer)
Self-contained breathing apparatus:
a small filtering device carried by a coal miner underground, either on
his belt or in his pocket, to provide him with immediate protection against carbon
monoxide and smoke in case of a mine fire or explosion. It is a small canister with
a mouthpiece directly attached to it. The wearer breathes through the mouth, the
nose being closed by a clip. The canister contains a layer of fused calcium chloride
that absorbs water vapor from the mine air. The device is used for escape purposes
only because it does not sustain life in atmospheres containing deficient oxygen.
The length of time a self-rescuer can be used is governed mainly by the humidity
in the mine air, usually between 30 min and 1 h
Self-rescuer:
the separation of a mineral interest from other interests in the land by
grant or reservation. A mineral dead or grant of the land reserving a mineral interest, by the landowner before leasing, accomplishes a severance as does his execution of a mineral lease.
Severance
a deep vertical passage used to enter the mine below; a shaft has to be sunk
or dug out until the vein of coal is reached. When a coal vein or layer was found,
then the digging began in a mainly horizontal direction to follow the vein
Shaft
an underground mine in which the main entry or access is by means of
a vertical shaft
Shaft mine
a large pulley used to guide a cable. Sheaves at the mine were placed at the
highest point of the tipple called the headframe. These sheaves guided the cables
that raised and lowered the cages.
Sheave
a mining method with a panel layout similar to longwall mining
but at a panel width reduced by approximately 50%. It uses continuous-mining
equipment for coal cutting and haulage and a specially designed hydraulic roof
support.
Shortwall mining
an excavating or coal-loading machine that uses a bucket mounted on and
operated by means of a handle or dipper stick that moves longitudinally on gears
and is lifted or lowered by cable. The entire machine is mounted on crawlers for
mobility, and the upper structure is mounted on rollers and rail for swing or turn
Shovel:
the slope of the sides of a canal, dam, or embankment. It is customary
to name the horizontal distance first as 1.5–1.0 or frequently 11/2:1, meaning a
horizontal distance of 1.5–1 ft vertical.
Side slope
the process by which a shaft is driven
Sinking:
a track-mounted vehicle used to hold trips or cars from running out of control.
Also it is a flat-bottom personnel or equipment carrier used in low coal
Skid
: a car being hoisted from a slope or shaft
Skip
a triggering mechanism that causes mine cars (pit cars) to dump its load
of coal or rock to a designated area at the mine.
Skipjack
small coal; the finest-sized soft coal, usually less than one inch in diameter
Slack
the nonmetallic product resulting from the interaction of flux and impurities in
the smelting and refining of metals
Slag
the primary combustion chamber for a cyclone-fired boiler. Ash from
the coal melts in the cyclone and is removed as a slag
Slag cyclone:
: the accumulation of coal ash on the wall tubes of a coal-fired boiler furnace,
forming a solid layer of ash residue and interfering with heat transfer.
Slagging:
a significant amount of dirt and rock excavated from the earth below that
is dumped into a pile.
Slag pile
a smooth, striated, polished surface produced on rock by friction
Slickenside
a long, narrow refractory chamber charged with coal heated in the absence
of air by adjacent heating flues. Ovens are arranged in batteries with heating flues
between each pair, like books on a shelf. Typical ovens are 457 mm wide, 12–15 m
long, and 4–6 m high.
Slot oven
the slow crumbling and falling away of material from roof, rib, and face
Sloughing:
a mixture of pulverized insoluble material and water.
Slurry
a pipeline that can transport a coal-water mixture for long distances.
Slurry pipeline
knocking on a roof to see whether it is sound and safe to work under
Sounding
a flat spike hammered into a wooden plug anchored in a hole drilled into the
mine ceiling from which is threaded a plumbline. The spad is an underground
survey station similar to the use of stakes in marking survey points on the surface.
A pointer spad, or sight spad, is a station that allows a mine foreman to visually
align entries or breaks from the main spad.
Spad:
the horizontal distance between the side supports or solid abutments along
sides of a roadway
Span: t
bubbling a gas into the bottom of a pool of liquid
Sparging
US Bureau of Mines term for durain with some vitrain and clarain and
small amount of fusain.
Splint coal
any division or branch of the ventilating current; also, the workings ventilated
by one branch. Also, to divide a pillar by driving one or more roads through it
Split
coal that is disturbed by layers of other geologic material, usually layers
of shale
Split coal
the overburden or non-coal material removed in gaining access to the coal or
mineral material in surface mining
Spoil:
the self-ignition of coal through oxidation under
very specific conditions. Different types of coal vary in their tendency toward
self-ignition
Spontaneous combustion
a person whose occupation is to apply braking to the mine cars below by
means of placing wood blocks or wedges underneath the wheels to prevent them
from rolling down slight grades
Spragger:
the volume of coal (27,878,400 ft3; 789,428.38 m3; 1,032,
533.33 yd3) that covers 1 square mile to a thickness of 1 foot; the weight of coal
varies according to the rank.
Square mile-foot:
the settling, without breaking, of the roof and the gradual upheaval of the
floor of a mine due to the weight of the overlying strata.
Squeeze
the product gas evolved during complete combustion of a fuel.
Stack gas
a chain conveyor of a design similar to the face conveyor. It provides
a connection between the face conveyor and the section conveyor belt.
Stage loader
said of deposits and coal seams with a dip of from 0.7 to 1 rad
(40–60∘).
Steeply inclined
the noncombustible material used on top or in front of a charge or explosive.
Stemming
a mine gas containing a high proportion of hydrogen sulfide
Stinkdamp
the combustion of coal on a grate, which may be stationary or moving
Stoker firing
refers to a procedure of mining that entails the complete removal of all
material from over the product to be mined in a series of rows or strips; this is also
referred to as open cut, open pit, or surface mine
Strip mine:
the removal of earth or non-ore rock materials as required to gain access
to the ore or mineral materials wanted. The process of removing overburden or
waste material in a surface mining operation
Stripping
the unit amount of spoil or waste (overburden) that must be removed
to gain access to a similar unit amount of ore or mineral material
Stripping ratio
a glossy-black-weathering and nonagglomerating coal that is
lower in fixed carbon than bituminous coal, with more volatile matter and oxygen;
a rank class of nonagglomerating coals having a heat value content of more than
8300 Btu’s and less than 11,500 Btu’s on a moist, mineral-matter-free basis—this
class of coal is divisible on the basis of increasing heat value into the subbituminous C, B, and A coal groups.
Subbituminous coal
the bottom of a shaft, or any other place in a mine, that is used as a collecting
point for drainage water.
Sump:
to force the cutter bar of a machine into or under the coal. This is also
called a sumping cut or sumping in
Sumping
the all-important function of keeping the mine workings open. As a
verb, it refers to this function; as a noun it refers to all the equipment and
materials—timber, roof bolts, concrete, steel, etc.—that are used to carry out this
function
Support:
a mine in which the coal lies near the surface and can be extracted by
removing the covering layers of rock and soil.
Surface mine
: gas from which acid (sour) gases such as H2 S and CO2 have been
removed
Sweetened gas
synthetic crude oil produced by pyrolysis or hydrogenation of coal or coal
extracts
Syncrude
approximately 2:1 molar mixture of hydrogen and carbon
monoxide with varying amounts of carbon dioxide
Synthesis gas (syngas)
pipeline-quality gas that is interchangeable with
natural gas (mainly methane).
Synthetic (substitute) natural gas
residual gas leaving a process; gas produced in a refinery and not usually
required for further processing.
Tail gas
: a subsidiary gate road to a conveyor face as opposed to a main gate. The
tailgate commonly acts as the return airway and supplies road to the face.
Tailgate
: also known as foot section pulley. The pulley or roller in the tail or foot
section of a belt conveyor around which the belt runs.
Tailpiece
a term used in both belt and chain conveyor work to designate that portion of the conveyor at the extreme opposite end from the delivery point. In either
type of conveyor, it consists of a frame and either a sprocket or a drum on which
the chain or belt travels, plus such other devices as may be required for adjusting
belt or chain tension.
Tail section
an old time train locomotive consisting of ten wheels, also referred to
as a 4–6–0, four small wheels up front near the pilot (cow catcher) and six larger
wheels under the middle of the loco and zero wheels at the rear or under the cab
where the engineer sa
Ten-Wheeler
lateral or panel openings (e.g., ramp, crosscut).
Tertiary
a system of dust collection from rock or roof drilling. The drill steel
is hollow and a vacuum is applied at the base, pulling the dust through the steel
and into a receptacle on the machine
Through-steel
a collective term for underground wooden supports.
Timber:
the setting of timber supports in mine workings or shafts for protection
against falls from roof, face, or rib
Timbering
originally the place where the mine cars were tipped and emptied of their
coal; still used in that sense, although now more generally applied to the surface
structures of a mine, including the preparation plant and loading tracks. The tracks,
trestles, screens, and so on at the entrance to a colliery where coal is screened and
loaded
Tipple
a short or net ton is equal to 2000 lb; a long or British ton is 2240 lb; a metric
ton is approximately 2205 lb
Ton
: the smallest sieve size upon which is retained a total of less than 5% w/w
of a total sample.
Top size
a wrench that indicates, as on a dial, the amount of torque (in units
of foot-pounds) exerted in tightening a roof bolt.
Torque wrench:
: a gaseous mixture of coal gas and carbureted water gas manufactured from
coal with a heat content of 600 Btu/ft3.
Town gas
acid spoil with pH below 4.0; also spoil having amounts of minerals,
such as aluminum, manganese, and iron, that adversely affect plant growth.
Toxic spoil:
person whose duty it was to lay railroad track to selected areas wherein
miners could conveniently load the pit cars with coal
Trackman:
used in connection with moving self-propelled mining equipment. A
tramming motor may refer to an electric locomotive used for hauling loaded trips
or it may refer to the motor in a cutting machine that supplies the power for
moving or tramming the machine.
Tram
: a vertical or inclined connection between two or more levels and used as
an ore pass
Transfer:
location in the materials handling system, either haulage or hoisting,
where bulk material is transferred between conveyances.
Transfer point
a person, usually of a young age, who opened and closed doors down below
in the mine for drivers. The doors down below were used to guide the downcast or
airflow to desired areas of the mine.
Trapper
an apparatus in which coal is lifted vertically in a revolving
cylinder and dropped through an axially flowing stream of oxygen and steam.
Tumbling-bed gasifier
partial gasification or pyrolysis in a first step followed by
complete gasification of the resultant char in a second step
partial gasification or pyrolysis in a first step followed by
complete gasification of the resultant char in a second step
: a train of mine cars.
Trip
the idlers, located on the upper framework of a belt conveyor,
which support the loaded belt. They are so mounted that the loaded belt forms a
trough in the direction of travel, which reduces spillage and increases the carrying
capacity of a belt for a given width
Troughing idlers:
the analytical percentage by weight of coal carbon, hydrogen,
nitrogen, sulfur, oxygen, and ash; the determination by prescribed methods
of the ash, carbon, hydrogen, nitrogen, oxygen (by difference), and sulfur
contents—quantities of each analyzed substance are reported by percentage for
the following conditions: as-received, dried at 105 ∘C (221 ∘F), and moisture-and
ash-free.
Ultimate analysis
to cut below or undermine the coal face by chipping away the coal by pick
or mining machine; in some localities the terms undermine or underhole are use
Undercut
also known as a deep mine; usually located several hundred feet
below the earth’s surface, an underground mine’s coal is removed mechanically
and transferred by shuttle car or conveyor to the surface.
Underground mine
an enlargement of an entry, drift, or level at a shaft at which
cages stop to receive and discharge cars, personnel, and material. An underground
station is any location where stationary electrical equipment is installed. This
includes pump rooms, compressor rooms, hoist rooms, battery-charging rooms.
Underground station:
reserves that are yet to be discovered; the term and the associated speculative data are often used in reserve estimation.
Undiscovered reserves
a long train of between 60 and 150 or more hopper cars, carrying only
coal between a single mine and destination; a railway train designated to achieve
economies of scale by transporting a single commodity (such as coal), loading
fully and operating nonstop.
Unit train
a type of coal cutting machine which is designed to make
horizontal cuts in a coal face at any point between the bottom and top or to make
shearing cuts at any point between the two ribs of the place. The cutter bar can be
twisted to make cuts at any angle to the horizontal or vertical
Universal coal cutter:
a shaft through which air leaves the mine
Upcast shaft:
the act or process of valuing or of estimating the value or worth; appraisal.
Valuation
the rate of airflow in lineal feet per minute.
Velocity
a macroscopic coal constituent (lithotype) that appear as brilliant black
bands of uniform appearance and greater than 10−2 mm thick.
Vitrain:
a microscopic coal constituent (maceral) that appears translucent by transmitted light and gray in reflected light; termed anthraxylon when viewed by transmitted light
Vitrinite:
a general term for pore space or other openings in rock. In addition to pore
space, the term includes vesicles, solution cavities, or any openings either primary
or secondary
Void
a procedure used in a laboratory before preparation plant
design to determine the cleaning processes to be employed and used during
normal operation to evaluate the performance of the cleaning equipment and the
amenability of the raw coal feed to the cleaning processes chosen.
Washability analysis:
the sudden erosion of soft soil or other support surfaces by a gush of water;
if a washout occurs in a crater-like formation it is a sinkhole
Washout
a mixture of carbon monoxide and hydrogen formed
by the action of air and then steam on hot coal or coke and enriched with hydrocarbon gases from the pyrolysis of oils
Water (carbureted blue) gas:
: an instrument that measures differential pressures
in inches of water.
Water gauge (standard U-tube)
a piece of wood tapering to a thin edge and used for tightening in conventional timbering
Wedge:
fracturing and lowering of the roof strata at the face as a result of mining
operations, as in taking weight.
Weight
: carbon monoxide, CO. A gas that may be present in the afterdamp of a
gas- or coal-dust explosion, or in the gases given off by a mine fire; also one of the
constituents of the gases produced by blasting. Rarely found in mines under other
circumstances. It is absorbed by the hemoglobin of the blood to the exclusion of
oxygen. One-tenth of 1% (0.001) may be fatal in 10 min.
White damp
the thickness of a lode measured at right angles to the dip
Width
the excavation, loading, and removal of coal or ore from the ground; winning follows development.
Winning
secondary or tertiary vertical or near-vertical opening sunk from a point
inside a mine for the purpose of connecting with a lower level or of exploring
the ground for a limited depth below a level
Winze
: a steel wire rope used for winding in shafts and underground haulages.
Wire ropes are made from medium carbon steels. Various constructions of wire
rope are designated by the number of strands in the rope and the number of wires in
each strand. The following are some common terms encountered: airplane strand,
cable-laid rope, cane rope, elevator rope, extra-flexible hoisting rope, flat rope,
flattened-strand rope, guy rope, guy strand, hand rope, haulage rope, hawser, hoisting rope, lang lay rope, lay, left lay rope, left twist, non-spinning rope, regular lay,
reverse-laid rope, rheostat rope, right lay, right twist, running rope, special flexible
hoisting rope, standing rope, towing hawser, transmission rope
Wire rope
when a coal seam is being squeezed by pressure from roof and floor, it
emits creaking noises and is said to be working; this often serves as a warning to
the miners that additional support is needed.
Working
any place in a mine where material is extracted during a mining cycle
Working face:
from the outby side of the last open crosscut to the face
Working place:
the entire system of openings in a mine for the purpose of exploitation
Workings
from the faces to the point where coal is loaded onto belts or rail
cars to begin its trip to the outside.
Working section
