Mining & Processing
Mining will be carried out using conventional open pit techniques. An Owner-mined open pit operation is planned with hydraulic shovels, loaders and mining trucks. Certain support activities such as explosives manufacturing, and blasting will be outsourced.
Production drilling of the 10 m benches will be by blasthole drill rigs with both rotary and down-the-hole drilling capabilities. Blast holes will be loaded with bulk emulsion. The majority of the excavation in the pit will be carried out by two 29 m3 hydraulic face shovels, one 29 m3 hydraulic excavator, and two 30 m3 front-end wheel loaders. The shovels and loaders will be matched with a fleet of 240-ton class mine trucks.
The final dimensions of the open pit will be 1.8 km long, 1.0 km wide and 600 meters deep. The design of the open pit incorporates the presence of historical openings from previous underground mining activity. Most of the other underground openings are backfilled with sand fill or rock fill.
Mining of the Greenstone open pit will occur in five main phases preceded by a starter pit. Waste rock will be placed in five distinct waste dumps with four located around the pit and one further to the south. The open pit will generate 690 Mt of overburden and waste rock over the life of mine (“LOM”) for an average LOM strip ratio of 5.1:1. Reserves equal 135 Mt of ore at 1.27 g/t Au.
The life-of-mine plan includes 13 years of Mine production, preceded by a preproduction period of 20 months. Once the open pit is depleted, the plant will process low grade stockpiled material for 9 months.
The gold recovery process for the Project consists of a crushing circuit (gyratory and cone), a grinding circuit (HPGR and ball mill), pre-leach thickening and cyanide leaching, a carbon in pulp (“CIP”) circuit, carbon elution and regeneration, electrowinning and gold refining, cyanide destruction and tailings disposal. The plant is designed to operate at a throughput of 27,000 t/d. The process operation schedule is 24 hours per day, 365 days per year, with an overall availability of 92%.