Which type of coal is the most widely used for commercial purposes?

Bituminous coal is the most widely used and most commercially important type of coal. It is plentiful, has a good heat value and is suitable for many industrial purposes, including electricity generation and steel making.

Characteristics of bituminous coal:

• It is a dense, black or dark-brown coal, often with bands of bright and dull material.
• Its carbon content is about 45 to 86 per cent, higher than lignite but lower than anthracite.
• It has a high calorific (heat) value.
• It is named after bitumen, a tar-like substance released when it is heated.

Uses of bituminous coal:

Thermal power generation: most of the coal burned in power plants (steam coal) is bituminous or sub-bituminous.

Metallurgical (coking) coal: certain bituminous coals, when heated without air, form coke, a hard, porous fuel used in blast furnaces to smelt iron ore into iron. This is vital for the steel industry.

Bituminous coal in India:

• Most of India's Gondwana coal is bituminous, much of it of non-coking, high-ash quality.
• Coking coal is found mainly in the Damodar valley coalfields of Jharkhand and West Bengal.
• Because Indian coking coal has a high ash content, India imports large amounts of good-quality coking coal, mainly from Australia.

The grades of coal (lowest to highest carbon content):

• Peat: the first stage of coal formation, with low carbon and high moisture; it burns with a lot of smoke.
• Lignite (brown coal): low-grade, moist coal.
• Bituminous coal: the most common and most widely used.

Anthracite: the highest grade, with the most carbon (over 86 per cent), hard and shiny, burning with little smoke; it is scarce. In India, small amounts are found in Jammu and Kashmir.

Why not the other options?

• ✗Anthracite is the best quality, but it is rare and costly, so it is not the most widely used.
• ✗Lignite is a low-grade coal used mainly in nearby power plants.
• ✗Peat has the lowest carbon content and is used only locally.