Studies and theory tell us the ball size is distributed in a linear order (ie the sizes are uniformly distributed).

You start will balls of the same size. You feed new balls in when the mass drops to measurable level, maybe 1-2%. This means that eventually the distribution goes into equilibrium. You then find that each size held in the mill is in equal representation.

You can obtain facts on this discussion by reading the papers delivered at the comminution SAG conference in Vancouver, BC Canada. The last conference was just held in September 2006, and before in 2001, and before that in 1989.

We have investigated this phenomenon using coordination number theory being proportional to wear rates. ■

SAG CONFERENCE 2006

September 23 - September 27, 2006

Vancouver, British Columbia, Canada

FOURTH INTERNATIONAL CONFERENCE

ON

AUTOGENOUS AND SEMIAUTOGENOUS GRINDING

TECHNOLOGY

http://www.sag2006.org/default.asp?notice=true ■

I snipped off a Google reference that gives some understanding, albeit, it does not go to the heart of your question:

http://books.google.com/books?id=GVA...ct=result&cd=1

We have done a fair bit of research that is not published in the area of SAG and ball mills. I hope you get a start on your journey. ■