Mining will be carried out using conventional open pit techniques with 10 m benches. An Owner-mined open pit operation is planned with hydraulic shovels 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 blast hole drill rigs with both rotary and down-the-hole (“DTH”) drilling capabilities. Blast holes are loaded with bulk emulsion. The majority of the loading 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 216 t payload mine trucks.
The presence of underground stopes was considered when designing the pit mainly for the void in the F-Zone, which is 150 m high and 30 m wide. Most of the other underground openings are backfilled with sand fill or rock fill.
Mining of the Greenstone main 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 generates 689.6 Mt of overburden and waste rock (inclusive of historic tailings and underground backfill) over the life of mine (“LOM”) for an average LOM strip ratio of 5.1:1.
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%.