AMIT 135: Lesson 8 Rod Mills – Mining Mill Operator …
J R = fraction of mill volume occupied by rods. Φ c = fraction of critical speed. The Rowland and Kjos equation indicates that power draw is a function of the fraction of the critical speed for the mill. Marcy mills are recommended to operate a peripheral speeds governed by the following relationship : Peripheral Speed= 108.8 D 0.3 meters/ min