Coal Frequently Asked Questions
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
- the degree of transformation of the original plant material into carbon, ranging from anthracite – the hardest – down through bituminous, sub-bituminous and lignite
- 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