It consists in wet-stamping coarsely crushed ore, settling the sands and slimes produced, and grinding and amalgamating them in steam-heated iron pans with or without the use of chemicals (salt and copper sulphate).
The slimes are treated chemically for the separation of the metals contained in them.
The process is rarely applied to ores direct; free-milling ores are generally amalgamated, and the tailings and slimes, after concentration, operated upon.
Of gold to the metric ton (2000 ib), is stamped and amalgamated, and the slimes and tailings, containing about 32 dwts.
After well washing with water, the slimes are roughly dried in bag-filters or filter-presses, and then treated with dilute sulphuric acid, the solution being heated by steam.