What is coal?
Coal is organic. It is formed from decayed plant materials. Pressure and heat compact the material into a solid, a process known as coalification.
Coalification has an important bearing on coal's physical and chemical properties and is referred to as the “rank” of the coal. In general, the longer the organic material is subjected to heat and pressure, the higher its rank and the more carbon content will be contained per unit of weight. Ranking is determined by the degree of transformation of the original plant material to carbon. The ranks of coals, from those with the least carbon to those with the most carbon, are lignite, subbituminous, bituminous, and anthracite.
Lignite and subbituminous coal (brown coal) are low-ranked coals
- Used only for the generation of electricity.
Bituminous coal and anthracite (hard coals) are high-ranked coals
- Used for thermal purposes
- Premium-grade bituminous coal (metallurgical coal, coking coal, or steelmaking coal) is used to produce coke, which is a key ingredient in iron and steelmaking.
Anthracite, the highest-ranked coal (smokeless) can be used for metallurgical purposes or is sometimes used for household cooking and heating fuel.
How does one type of coal differ from another?
Coal is classified according to:
energy value – how much energy is released when coal is burned
degree of transformation into carbon
moisture content – coals high in carbon and low in moisture are ranked the highest
composition – coal is predominantly carbon but may also contain varying amounts of hydrogen, oxygen, nitrogen and sulphur
The world's total proven recoverable coal reserves are 1,000 billion tonnes (t) spread over more than 70 countries. Coal was the energy source that boosted the industrial revolution of the 19th century and launched the electric era in the following century.
Graphic Source: Coal Information , International Energy Agency
It was the primary source of energy until the late 1960s when it was overtaken by oil. Coal-fired power generation currently provides more than 40% of the world's total electricity.
Source: Coal-Other Information , Natural Resources Canada
Coal Mining in Alberta
Alberta’s coal mining started in the late 1800’s, Alberta averages 25 to 30 million tonnes of coal production each year from its nine mines. Coal-bearing formations underlie about 300,000 square kilometres, almost half of Alberta.
In 2014, nine mine sites produced approximately 30.8 million tonnes (Mt) of marketable coal. Subbituminous coal accounted for 78 per cent of the total, metallurgical bituminous coal the remaining 22 per cent. Six surface mines produce subbituminous coal.
Mining in Alberta is regulated by the Alberta Energy regulator. Mining activities and reclamation are subject to review and approval through Alberta Environment and Parks. Alberta Human Services is responsible for mine safety.
Environmental management is an important part of developing, running and closing down a mine. Mining companies develop and carry out plans to minimize impacts on air, land, water and wildlife. Companies use a variety of techniques to reclaim and restore mined lands.