ABSTRACT
The mining activities of gold conducted by an individual miner or small-scale enterprise with limited capital investment and production output can be termed as artisanal gold mining (ASGM). Amalgamation is the most important unit operation of the ASGM, in which mercury in its elemental form is used to obtain the amalgam alloy with trapped gold. Starting from the sixteenth century, amalgamation was the major technique used in the mining of gold. Whole ore amalgamation is the process of bringing mercury into contact with the entire mining product, typically added either when the ore is being ground in mills or when the slurry produced from grinding is passed over a mercury coated copper plate. Amalgamation of grinding concentrates can be done in batches, in which small gold particles are liberated to achieve a high yield of gold. The most common process to decompose amalgams is by increasing the temperature above 460°C when all mercury compounds are evaporated separating the gold.
