Conventional crush-grind-CIP to produce gold-silver dore
Forecast mine life
The Pajingo mine's mineralisation is hosted in structurally controlled epithermal quartz veins within an andesite host rock. In general, veining strikes grid east with tensional jogs producing high grade pods trending grid east-north-east. The main mineralised veins in the Vera Nancy corridor plunge at about 20 degrees to grid east.
Most ore bodies comprise a main vein, which carries the bulk of the precious metals, and splay veins that can contain economic grades but usually only when close to the main vein. The mineralised structures can vary from less than 1 metre to 15 metres in width, but are generally 1 metre to 3 metres wide.
Underground mining is based on modified avoca and longhole open stoping methods with ore hauled to surface via decline. Open pit mining is by conventional drill and blast, load and haul methodology. An impressive turnaround was achieved at Pajingo in FY2012. Gold production of 75,747oz was well above guidance and cash operating costs of A$780/oz were well below guidance. This is an excellent outcome and a direct result of the re-tooling and capital investment programs implemented by Evolution to improve Pajingo's long-term sustainable performance.
Ore is free milling and is treated on site by conventional crush-grind-CIP processing to produce gold-silver- dore. The processing plant has capacity to process up to 650,000 tonnes per annum and is currently operated at 350,000 to 450,000tpa. Ore production is planned to be increased to utilise the latent capacity in the processing plant. Metallurgy is simple and gold and silver recoveries are very high, typically 94 to 95%.