### A new methodology to obtain a corrected Bond ball mill work index …

(5): (5) W = 10 ∙ W i ∙ 1 P 80-1 F 80 where: W is the energy input (work) in kilowatt-hours per metric ton; W i is the work index (or Bond work index) in kilowatt-hours per metric ton; and P 80 and F 80 are the 80% product and feed passing sizes, in micrometers. All three comminution theories can be derived from the basic differential Eq.