There were over 100 in the mill. There also were gravity traps and sluices to recover coarse gold. The deslimed fine sands (minus 7 mesh) from the ball mills flowed over riffles on the tables in a stream of water. The devices driven by a belt in the foreground imparted shaking motion to produce three products: (1) a concentrate of heavy minerals (2) middlings for retreatment and (3) tailings for disposal. The feed to the tables had about 4 dollars worth of gold per ton. After a series of treatments including screening and regrinding the concentrate was worth over 20 thousand dollars per ton.