"The slurry is piped to wash-tanks on the 3rd floor where it is washed with hot and cold water. The water being pulled through the slurry which is contained in the top half of the tanks and supported on filters. The slurry is now in a hardened state and is tested in the laboratory to ascertain if enough of the soluble salts have been removed. If the salt level is too high the slurry is re-washed in the same tanks. The hardened slurry is dug out by hand and shovelled down on an adjoining hopper to another tank on the 2nd floor where it is again mixed with water and agitated."