Ball mills are commonly used in the manufacture of Portland cement and finer grinding stages of mineral processing, one example being the Sepro tyre drive Grinding Mill. Industrial ball mills can be as large as m (28 ft) in diameter with a 22 MW motor,  drawing approximately % of the total world's power (see List of countries by electricity consumption ).
Up to six stationary grinding rollers roll on a rotating grinding table. The material is drawn in between the rollers and grinding table and ground by pressure and shear. The required pressure forces are produced by a lever system comprising, among others, a roller arm, along with a hydropneumatic tension system.