My mill has 20 stamps. A gap at the end of the batteries makes it apparent there was at one time 10 more. The iron parts of the 10stamp batteries were made from styrene and brass wire, with Grandt Line wheels and NBW castings. After the ore had been stamped to fine sand, it was washed over amalgamation plates— copper plates impregnated with mercury— which siezed the particles of free gold ...