Grinding pans varied in design, but generally worked on the same principal. Sands were introduced to the pan via a central spindle, then ground as they moved outwards, between a fixed annular plate (die) and a rotating annular plate.
Grinding Pans, by Robert Kaufman
Details
Grinding pans varied in design, but generally worked on the same principal. Sands were introduced to the pan via a central spindle, then ground as they moved outwards, between a fixed annular plate (die) and a rotating annular plate.