A device used for grinding solid fuels such as coal as finely as possible with a minimum of power required to achieve a given particle size distribution. Pulverized fuels are used in power stations for electricity generation and also for boilers for raising steam. The small particle size enables the fuel to be carried into the furnace with a current of air and allows for rapid and controlled combustion. Pulverizers are classified by the speed of operation and include various forms of mill such as the ball mill.