Coal Fuels

Coal is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. Coal is a readily combustible black or brownish-black rock. It is a sedimentary rock, but the harder forms, such as anthracite coal, can be regarded as metamorphic rocks because of later exposure to elevated temperature and pressure. It is composed primarily of carbon along with assorted other elements, including sulfur. It is the largest single source of fuel for the generation of electricity world-wide, as well as one of the largest sources of carbon dioxide emissions, which is considered the primary cause of global warming. Coal is extracted from the ground by coal mining, either underground mining or open pit mining (surface mining).

Outcrop coal was used in Britain during the Bronze Age (2-3000 years BC), where it has been detected as forming part of the composition of funeral pyres. It was also commonly used in the early period of the Roman occupation. Evidence of trade in coal (dated to about AD200) has been found at the inland port of Heronbridge, near Chester, and in the Fenlands of East Anglia, where coal from the Midlands was transported via the Car Dyke for use in drying grain. Coal cinders have been found in the hearths of villas and military forts, particularly in Northumberland, dated to around AD400. In the west of England contemporary writers described the wonder of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath) although in fact easily-accessible surface coal from what is now the Somerset coalfield was in common use in quite lowly dwellings locally.