CHAPTER VII

GOLD EXTRACTION

(SECONDARY PROCESSES AND LIXIVIATION)

Choosing the plant---Various ores and their constituents--Amalgamation--Various concentrators--Percussion tables--Frue vanner--Pan concentration--Simultaneous grinding and amalgamating condemned--Watson and Denny pan--Good machines often condemned--Procedure in ore treatment--Duncan pan--Calcining--Rotatory amalgamator--Steaming concentrates--Dry amalgamation--Sulphuric acid and sickened mercury--Amalgamation without overflow--Experiments--Steam as an agent in gold extraction--Lixiviation by chlorine--Various processes--Mount Morgan--Cyanide process pp. 87-99