riu conference tues 22/2, page-21

The ball mill simply grinds the ore rock into finer powder so that there is a better recovery rate via chemical leeching.
Ball mills can be dry, wet or both and require considerable energy to run.

primary jaw crushers crush rock from say a cubic meter to 100 mil crusher run

Secondary jaw crushers can reduce this crusher run down to
30 mil run

Cone crushers can then crush this down to 10 mil crusher dust (roadbase)

And then the ball mill can reduce the ore down to a dust.

two three or four stages may be used depending on how
the ore comes out of the mine.

Cheers
Moorookamick