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 is comprised of gold, silver and copper. Later andesitic volcaniclastics overlies a rhylotic sequence which in turn underlies a package of sediments and conglomerates. Mineralisation is structurally controlled which is exclusively hosted within the advanced argillic altered rhyodacite. Discrete and discontinuous steeply dipping ENE trending breccia dominated quartz - sulphosalt infilled veins form high grade bonanza lodes. Paragenetically, the sulphosalts replace sphalerite and galena which are associated with late stage copper sulphides. Coarse gold occurs as small grains (0.1 mm) at quartz-sulphide infill contacts and in sulphosalts. Basaltic/doleritic dykes which mirror pre existing structures cross cut mineralisation.

Production is derived solely from the V2 deposit following the completion of the silver rich A39 deposit in FY14. The V2 deposit is flat lying and situated 20m to 180m below surface and is approximately 70m thick with a 500m by 500m areal extent. Open pit mining is by conventional drill and blast, load and haul methodologies, mining 5m benches in 2.5m.

Underground commenced full production in March 2020, three months ahead of schedule, to provide higher grade feed to the plant.

The low grade ore is blended with high grade ore to optimise concentrate grade generation matching the plant capability.

Crushing:
Primary crushing: TEREX JW42-AS849 Jaw Crusher

Grinding:
OUTOTEC 7.32m x 3.8m SAG mill. Forged steel 125mm balls and 105mm balls.

Screening:
LUDOWICI UHS-1-1200/300-2 (COF)

Recycle crusher:
2 x Sandvik CH420 cone crushers feed size 18 to 150mm.

The Mt Carlton processing plant was commissioned in 2013 and ore is sourced from the V2 gold-copper-silver deposit which is processed on site to produce a concentrate and shipped to China for smelting. The process plant has a current capacity of 840ktpa. Approximately 10-15% of gold feed is recovered through a gravity circuit prior to the flotation circuit to produce dore gold bars which are sold to the ABC Refinery in Sydney. The gravity circuit was installed in 2017 and has lifted recoveries from 88% to 90-91%.