Crushing, grinding and bulk sulphide flotation to produce a polymetallic concentrate
Nominal treatment rate
Design capacity of 800ktpa
Current mine life
The Mt Carlton project is a high-sulphidation epithermal style deposit with mineralisation occurring within felsic volcanic rocks on the northern margin of the Permian Bowen Basin. The project comprises gold, silver and copper primarily as copper arsenic sulphides (enargite) and silver arsenic sulphides (tetrahedrite/polybasite) and some native gold (within pyrite).
The Mt Carlton deposit comprises two discrete zones: the large gold dominant V2 deposit and the smaller, silver rich A39 deposit. The V2 deposit is flat lying and situated 20 metres to 180 metres below surface andis 70 metres thick with a 500 metre by 500 metre areal extent. The two deposits are located 200 metres apart.
The stratigraphy in the Mt Carlton area is almost flat lying with a gentle 10 degree southerly dip. Sulphide veins dipping at moderate to steep angles to the NW host a majority of the known economic mineralisation.
Following the completion of the A39 open pit in FY14, mining production is now derived solely from the V2 open pit, utilising conventional drill and blast, load and haul methodologies. Mining equipment is contracted under a dry-hire arrangement and is operated by Evolution employees, mining 5 metre benches in 2.5 metres flitches.
The V2 pit will have a life-of-mine strip ratio of 2.7:1 and will be mined over nine years. The low-grade ore will be stockpiled and processed after depletion of the high-grade ore, to be processed post completion of open pit mining.
Ore is processed via conventional technology, consisting of crushing, grinding and flotation to produce a polymetallic concentrate. Commercial production commenced 1 July 2013.