### A Method of C alculating Autogenous/ Semi-Autogenous Grinding Mill .

650 μm. These ﬁ nes proceed to the ball mill improving the ball mill efﬁ ciency. Also, the plotted rod mill P80 value, as shown in Figure 1, is 2900 μm. If the rod mill ﬁ nes are taken into account the rod mill product can be theoretically corrected to show a P80 of