Mining and Processing
Conventional open pit mining methods are used to mine the Detour Lake deposit utilizing a current fleet size of 32 haul trucks (CAT 795F - 300 tonnes), 2 electric cable shovels (48 m3), 4 hydraulic shovels (28 m3), 10 drills and various ancillary equipment to support the mining operation.
The mining operation is using a conventional gravity, cyanidation and carbon-in-pulp processing facility currently operating at 60,000 tpd.
The crushing circuit includes a larger gyratory crusher (60"X113" HD equipped with 1,000 kW) and the addition of a secondary crushing circuit (2X750 kW crushers). In addition, this system is complemented with additional crushing capacity in the pebble crushing circuit (2X750 kW pebble crusher).
The grinding circuit consists of two parallel lines, each having one twin pinion semi-autogenous (SAG) mill (36'X20') and one twin pinion ball mill (26'X40.5'). The gravity circuit is expected to recover approximately 30% to 40% of the gold. The remaining gold in ore is sent to cyanidation followed by carbon in pulp (CIP) gold recovery. After carbon stripping, the gold is processed through electro-winning cells prior to gold pouring. The overall gold recovery is estimated at 91.5% for 2016 to 2018, and increasing to 92% thereafter.
The cyanide solution is recycled to the head of the circuit to reduce operating costs and environmental impact. The remaining stream is detoxified through an SO2/air system before tailings deposition. The Company is using the same location for the tailings impoundment facility as the former operation. The current design framework will be expanded to a second and then a third containment system with capacity for approximately 650 million tonnes.