21. First, the alloy materials are combined in a ball mill and ground to a fine powder. 22. However, the grinding action is poor, and the product is often re-ground in a ball mill . 23. SAG mills are characterized by their large diameter and short length as compared to ball mills . 24. A new rod mill was added in 1995, and a new grinding ball mill was installed in 1996. 25. Unlike ball mills , feed to the mill must be regular and uninterrupted; otherwise damaging resonant vibration sets in. 26. These ingredients are processed in a ball mill , basically a spinning drum with non-sparking ceramic or lead balls. 27. The floats are sent to an Ersel ball mill operating in closed circuit with a double-deck sizing screen. 28. The Ball Mill by example it was an prototype of highly sophisticated design and it was not proven. 29. However the ball mill was unable to cope with the high volumes of ore in the early 1940s. 30. This gives good cement performance, and reduces energy consumption by 20-40 % compared with a standard ball mill system.
