### Cement mill notebook - LinkedIn SlideShare

Jan 07, 2015· 3. Friction between the lining and the grinding media. 4. Internal friction mill charge. Figure: Grinding media 4.4.1 Grinding Ball Charge in Mills: According to Levenson, the optimum grinding ball charge should be r - 0.16D The degree of ball charge varies with in the limit of 25 and 45%. A ball charge below 25% causes sliding of the balls.