Overview

The Detour Lake open pit mine is located in northeastern Ontario, approximately 300 kilometres northeast of Timmins and 185 kilometres by road northeast of Cochrane, within the northernmost Abitibi Greenstone Belt. The operation is situated in the area of the historic Detour Lake open pit/underground mine operated by Placer Dome which produced 1.8 million ounces of gold from 1983 to 1999.

Detour Gold acquired the property in January 2007, completed a feasibility study in June 2010 and commenced gold production in February 2013. An updated life of mine plan, completed in March 2017, shows a mine life of 23 years with an average gold production of 656,000 ounces per year. The life of mine plan includes the development of the West Detour project which is currently being permitted.

Operating Data

2016 2015 2014 2013
Total mined (Mt) 87.4 90.7 76.8 60.5
Ore milled (Mt) 20.8 19.8 17.7 11.2
Head grade (g/t Au) 0.9 0.88 0.88 0.75
Recovery (%) 89 91 91 86
Ounces produced (oz) 537,765 505,558 456,634 232,287
Ounces sold (oz)1 527,727 486,243 423,013 212,522
Total cash cost (US$/oz sold) $ 746 $ 775 $ 942 $ 1,182
AISC2 (US$/oz sold) $ 1,007 $ 1,056 - -

1 For Q3 2013, pre-commercial production not included.
2 For AISC, the Company adopted this measure effective January 1, 2015.

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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 fleet will be increased in the next few years in order to meet the mine production schedule of the new life of mine plan.

The mining operation is using a conventional gravity, cyanidation and carbon-in-pulp processing facility currently operating at approximately 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 currently recovers approximately 25% 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 to average 90.6% for 2017 and 2018, and 92.7% for the life of the mine.

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 tailing facility will be expanded to a second and then a third containment system with capacity for approximately 650 million tonnes.