Make a Ball Mill in 5 Minutes - InstructablesJul 26, 2007 . This is for all the pyro nuts that I came across on Instructables. This can be used to grind chemicals to a very fine grain or to polish rocks.Wiki says "A ball.how to build a ball mill for gold,The economic benefits of minimized mill gold lock-up at . - SAIMMPlant1 showed that gold lock-up follows a parabolic profile as indicated in Figure 2. With a new grid liner, lock-up gold starts at zero. As the balls wedge into the pockets, concen- trates build up between the balls inside the pockets, and gold concentrate starts to accumulate behind the liners. At a life of ±. 60%, the grid liner.