Coal is used as a raw material for many purposes in many industries.
Coal can be used in thermal-power stations to generate heat and thus electricity.
Coal can also be used for the production of many fertilizers, dyes, chemical-reagents etc.
The by-products of coal are also very useful it includes phenol tar, sulphur, napthalene etc.
So, it can be seen that coal is useful in many cases. So, most industries are concentrated around coal mines.