Ann: Lake Torrens IOCG Project - Drilling Update, page-240

Olympic Dam is one of the most complex copper mining/smelting operations globally. Basically what happens is that the uranium is removed first and that’s processed under a different circuit.

The copper, gold and silver is put through hydromet plant where impurities are removed. Then the concentrated copper/gold/silver is put through the smelter where the copper is removed. This leaves the gold/silver with in the slag material. This is then processed again to remove the gold and silver.

That’s a simpler flow sheet, but basically 83-90% of copper is recovered, only 50-60% of the gold/silver is removed and poured into dore (bars). It’s a complicated process due to the high iron content and most of the value is in the copper. The variability in the strata and copper compounds (chalcocite, Bornite and chalcopyrite) creates a need to mix the ore to get high copper recoveries at a regular percentage.