Kirkland Lake (Macassa) gold mine

The Macassa gold mine is located approximately 600km north of Toronto, in the eastern part of Northern Ontario, Canada. It is an underground gold mine utilising underhand cut and fill, long-hole stoping and mechanised overhand cut and fill. The mining method is selected based on the ground conditions, geotechnical parameters, orebody gradient and dilution. ROM ore reports to the mill where it undergoes three stages of crushing, followed by three stages of grinding, the slurry then reports to the pre-oxidation treatment tanks before being pumped to the thickener. The overflow reports to the carbon-in-column circuit whereby approximately 75% of gold is recovered, whilst the underflow reports to the leaching circuit. Following the leaching circuit, the pregnant solution is pumped to the carbon-in-pulp circuit, the loaded carbon will then be washed and stripped, before the eluate reports to the electrowinning circuit and then the precious metal sludge is smelted to produce a doré.