Augur (or Punch) Mining
A form of unmanned underground mining offering minimal
capital cost and relatively short start up periods.
Large augers or remote-controlled mine equipment bore
into coal seams from roadways established on the floor
of surface exposures.
Bank Cubic Metres (BCM)
The volume of waste rock above and between coal seams in
an open-pit mine is commonly measured in bank cubic
Raw coal mined in open pits is often tumbled in large
rotary screens where unwanted large rocks mixed with
coal during extraction process are removed prior to the
coal being delivered to a processing plant.
Clean (Product) Coal
Coal which has been processed in a plant in order to
meet a sales contract product specification and is ready
to load onto railcars or other transportation means.
Dryers normally fuelled by natural gas or coal are
commonly a component of coking coal processing plants.
They are used to remove the moisture content of product
coal prior to loading onto unit trains for shipment from
Geotechnical studies are undertaken during the planning
and operation of open-pit coal mines. Some of the more
common subjects for geotechnical tests are: soil
stability, rock stability and strength, ground water,
The deepest part of the perimeter of an open pit mine.
In Situ Coal
Coal found in its natural state prior to mining.
Facilities comprising storage silos, weight meters and
conveyors used to load coal onto unit trains.
An automated form of underground coal mining
characterized by high recovery and extraction rates,
feasible only in relatively flat-lying, thick, and
uniform coalbeds. A high-powered cutting machine is
passed across the exposed face of coal, shearing away
broken coal, which is continuously hauled away by a
floor-level conveyor system. Longwall mining extracts
all machine-minable coal between the floor and ceiling
within a contiguous block of coal, known as a panel,
leaving no support pillars within the panel area. Panel
dimensions vary over time and with mining conditions but
currently average about 900 feet wide (coal face width)
and more than 8,000 feet long (the minable extent of the
panel, measured indirection of mining). Longwall mining
is done under movable roof supports that are advanced as
the bed is cut. The roof in the mined-out area is
allowed to fall as the mining advances.
Open Pit Mining
The common form of mining in Western Canada involves
specialized fleets of mobile equipment to drill, blast,
load and haul large volumes of rock and coal.
Pulverized Coal Injection.
Product Coal Specifications
– Negotiated maximum and minimum values for ASH,
VOLATILE, FIXED CARBON, SULPHUR, TOTAL MOISTURE and FREE
SWELLING INDEX are usually defined on coking coal sales
contracts. Coking coal is normally sold at a “Free on
Board” basis meaning at the sellers port terminal where
it is often tested by an independent laboratory for the
above specifications. Variance beyond contract
specifications may lead to penalty charges or in extreme
cases the rejection of purchase by the buyer.
The most common method of underground mining in which
the mine roof is supported mainly by coal pillars left
at regular intervals. Rooms are places where the coal is
mined; pillars are areas of coal left between the rooms.
Room-and-pillar mining is done either by conventional or
Run of Mine (Raw) Coal
Mined coal available for or delivered to a processing
plant. Many operations will subject the mined coal to
sizing and pre-cleaning with screening systems or rotary
breakers prior to delivery to processing plants.
These are man-made ponds constructed to catch and retain
surface drainage in order that sediments in the drainage
may settle to the bottom of the pond and not be
discharged into streams or rivers. They are normally
placed at strategic locations surrounding open-pit mine
waste dumps to safeguard against increased sedimentation
of surrounding water courses.
Specific Gravity (Rock & Coal)
density or specific gravity of rock and coal are
important in the operation and design of processing
plants where dense liquid media are often used to
segregate coal and rock mixtures. Specific gravities are
also applied to volumes in the calculation of coal
reserves where the relationship between ash content and
specific gravity are often applied.
The stripping ratio is the most
influential economic factor in the evaluation and
planning of open-pit coal mines. It represents the
volume of rock both above and within (partings) coal
seams expressed in Bank Cubic Metres (BCMs) which must
be mined to obtain 1 tonne of raw or clean coal. The
clean coal stripping ratio is more indicative of a
mine’s performance as it includes the expected
performance of the mine’s processing plant. Current
Western Canadian open-pit coking coal mines typically
operate with clean coal stripping ratios of between 7
and 8 to 1.
Coal sulfur occurs in three forms: organic, sulfate, and
pyritic. Organic sulfur is an integral part of the coal
matrix and cannot be removed by conventional physical
separation. Sulfate sulfur is usually negligible.
Pyritic sulfur occurs as the minerals pyrite and
marcasite; larger sizes generally can be removed by
cleaning the coal.
Blasting of waste volumes, measured in
bank cubic metres, is undertaken to produce material
capable of being loaded into haul trucks. Swell factors
are applied to the blasted rock to adjust for its volume
increase when blasted.
Particles of unwanted rock removed during the
processing of coal.
Man-made structures which contain
tailings and water and are designed to allow tailing
particles to settle to the bottom of the ponds.
Underground coal mining involves
specialized equipment which usually is restricted to
excavating within the roof and floor of the coal seams
being mined leaving areas of coal or pillars to support
the mining operations from caving in.
Wash (Processing) Plants
Coal plants segregate the
mined coal into different size categories and on mixing
it with water apply different mechanical processes and
equipment to separate the coal from rock or high ash
Rock found above and between coal seams being
mined within an open-pit mine boundary.
Locations which are selected as close as
practical to the limits of an open-pit mine where waste
rock is placed by haul trucks.