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10 November, 2012 Posted by Christopher Jenner Posted in Uncategorized
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Common Coal Mining and Processing Terms

The following is a list of some common terms used in coal mining and processing. This list has been compiled from posts written in the former glossary section – removed late 2012.

Know some vital slang or mining coal talk that I have missed? Let me know in the comments section.

*Please use “Ctrl + F” to search this document for terms.



Anthracite – an·thra·cite

(Rank of Coal)

A coal with a high carbon content and low amount of volatile material, also called hard coal. It is the most highly metamorphosed form of coal. Burns with a clean flame (blue flame).

Metamorphosed – met·a·mor·phose

(Process of change)

Metamorphism is the transformation in structure or composition of a material caused by an applied external agent. Commonly from pressure, reactive chemicals, shearing stress, high temperature or a combination of agents.

Auger Mining

(Coal mining technique)

Auger mining is a technique for recovering coal from a seam located behind a highwall (can also be used underground). One of the lower cost techniques for coal mining, it is usually carried out horizontally or slightly angled into a coal seam behind the highwall.

Backfill – back·fill

Backfill, to refill a mined or excavated area with the undesirables from the processed material, or the preliminary topsoil that was removed.

Diagenetic – di·a·gen·e·ic

(Process of chemical and physical change, coal)

Diagenetic (coal), a process whereby the physical and chemical structure of a deposited sediment changes during its conversion to coal.

Bituminous coal – bi·tu·mi·nous

(Rank of coal)

Bituminous coal is a soft form of coal containing bitumen (Bitumen – composed principally of hydrocarbons, is dark in color, comparatively hard and non-volatile). Is lower quality than Anthracite coal but higher than lignite coal. Formed from diagenetic and sub-metamorphic compression of peat bog material. See Metamorphosed.

Captive Mine

Captive mine; a mine who’s product is taken largely or wholly by the owners of the mine for their own use or for a subsidiaries use.


A dry, hard carbon substance produced by heating coal to high temperatures in the absence of air. The more volatile components of the base coal are driven off through destructive distillation. Used in the manufacture of iron and steel.

Coal Washing

Coal washing is a process designed to separate the coal particles based on size, density and shape. Achieved by allowing the coal to settle in the wash fluid.

Continuous Mining

Continuous Mining is an underground method of extracting coal. The process utilises a machine that is capable of handling the entire extraction process. The machine itself takes over the traditional cutting, drilling, blasting and loading stages of underground coal extraction. This is achieved by extracting coal from the seam while simultaneously transporting it by conveyor to the loading machine.

Drift Mine

(Mining technique)

A coal mine extended directly through a horizontal opening. Used when ore or minerals are found on the side of a mountain. Cheap and a relatively easy form of mining.

Electrostatic Precipitator

(Dust removal)

An electrostatic precipitator works by inducing a charge in a flow of gas to remove trapped particles. Used to remove fly ash from combustion gases prior to being released. Electrostatic precipitators are highly efficient forms of filtration, and minimally impede the flow of gasses.

Face (mining)

(Also pit face or mine face)

Face (mining) describes the area that is being worked/advancing. In coal mining, the face is where the coal seam is being worked.

Mine face – common term used in underground mining.

Pit face – common term used in surface mining.

Fly Ash

(Trapped particles in gas flow)

Very fine particles divided evenly; ash entrained in the flue gases arising from combustion of fuel.

Gasification – gas·i·fi·ca·tion

Gasification is the process of converting into gas. An organic or fossil base is converted into hydrogen, carbon monoxide and carbon dioxide by gasification.

Highwall (mining)

A highwall is an unexcavated face of exposed overburden (unwanted minerals overlying a useful mineral deposit) and coal or ore in an opencast mine or the face of an uphill side of a contour strip-mine excavation.

Lignite (coal)

(Rank of coal)

Other names: Brown Coal, Rosebud Coal

Lignite is a soft brown coal used primarily in steam electric power generation due to its low quality (the lowest rank of coal). The characteristics of lignite put it somewhere between coal and peat. It is a soft coal and has a high moisture content.

Liquefaction (coal) – liq·ue·fac·tion

Liquefaction (coal) is a method of converting coal into a synthetic liquid fuel. The process involves heating coal while adding a number of reagents to produce the synthetic liquid fuel. The fuel produced is similar in nature to crude oil and its refined products. The process is known to generate large volumes of waste.

Longwall Mining – long·wall

Longwall mining is a method of underground mining were a steel plow or rotating cutting drum mines a longwall of coal in a single slice. The drum/plow is mechanically pulled back and forth over the wall for hundreds of feet. The mined coal is then removed via conveyor.

Metallurgical Coal

Also known as: met coal

The types of coal carbonized to make coke for steel manufacture. Four important qualities for “met” coal are Volatility – which affects coke yield, the level of Impurities – which affects coke quality, Composition – which affects coke strength, and basic Characteristics – which affect coke oven safety. Metallurgical coal has a particularly high Btu, but low ash content.

Mine-Mouth Plant

A mine mouth plant is located near a coal mine. Usually a steam powered plant that delivers electricity by high voltage long distance lines. Mine mouth plants significantly reduce the cost of machinery and transportation associated with electricity generation from coal.

Outcrop (coal)

An Outcrop is a visible exposure of a coal seam where it intersects with the surface.

Overburden (mining) – o·ver·bur·den

Overburden is a unwanted mineral deposit overlying a useful mineral deposit. In coal mining,  it’s the layers of dirt and rock covering a coal seam. The overburden is removed and then replaced during surface mining.

Coal Preparation Plant

A coal preparation plant (CPP) is a facility that washes coal of soil and rock, preparing it for transport. The plant is usually located on the site and often has the capacity to serve a number of mines. The plant usually contains facilities for crushing, sizing, and washing run-of-the-mill coal.

Sub-bituminous (coal) – sub-bi·tu·mi·nous

(Rank of coal)

Sub-bituminous coal has a heating value between bituminous and lignite coal. Sub-bituminous coals have low fixed carbon content,  high percentages of volatile matter and high moisture content. Used primarily in steam electric power generation.

Sub-bituminous coals may be dull, dark brown to black, soft and crumbly at the lower end of the range, to bright jet-black, hard, and relatively strong at the upper end.

Rank of Coal

Rank of coal, the classification of coal by degree of hardness, moisture and heat content.

There are four major ranks of coal:Anthracite, Bituminous, Lignite, and Sub-bituminous

In terms of Btu content, anthracite has the highest, followed by bituminous coal, sub-bituminous and lignite.


Run-of-the-mine is the raw mineral extracted from the mine before any processing. In coal mining,  run-of-the-mine is the coal as it comes from the mine, not treated at a preparation plant.

Slurry Pipeline (coal)

A slurry pipeline is used for transporting a viscous mixture of coal and liquid medium (water). They can be used for short-haul-transport, such as from a port facility to a nearby power plant, reducing or eliminating the need for large stockpiles of coal.

Steam Coal

Coal used under power plant, and industrial steam boilers to produce electricity. Generally lower Btu content than metallurgical coal.

Surface Mine

A surface mine is a mine with mineral deposits located near the surface. In order to mine the deposits, the covering layer of soil (overburden) must be removed.

Tipple (coal) – tip·ple

A tipple is a surface processing structure for cleaning, sizing and automatically loading coal onto railway cars or trucks for movement to market.

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1 comment

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