The feed required for the Ball Mill is prepared by: O Sgle or multistage crushg and screeng. O Crushg, screeng and/or Rodmillg. O Primary Crushg and autogenousl semi-autogenous grdg. O Primary Ball Mill, with 25-40 mm Grdg Ball size (1" -1 S") feedg the secondary Ball Mill with Grdg Ball size of 20 mm. ( 14").