Mined ore contains only small concentrations of minerals. Each tonne from the open pit contains on average less than 5 kilogram of copper and less than one-third of a gram of gold. After travelling on the overland conveyer from the primary crusher, the ore arrives at the concentrator which uses a series of complex mechanical and chemical processes to turn it into the final product, ready for export. This product is called concentrate, a fine powder, containing between 25 and 30 per cent copper and smaller amounts of gold and other minerals.
Ore is fed through a series of mills to reduce its size in preparation for concentration. These include some of the largest mills in the world. Next, ground ore is moved to flotation tanks where it is mixed with water to allow copper, gold and silver to be skimmed off. A concentrate thickener removes excess water and leaves behind copper concentrate in powdered form.
The Oyu Tolgoi concentrator is the biggest industrial unit ever built in Mongolia. It contains enough steel to construct the Eiffel Tower three times and took more than 15.7 million individual work hours to build.
The concentrator covers an area 255 metres long and 144 metres wide. The concentrator produced its first copper concentrate on 1 February 2013 and commenced shipments to customers on 9 July 2013. The concentrator can process up to 100,000 tonnes of ore each day. The concentrator plant will be upgraded during underground construction to handle higher-grade ore and increased production.
About copper concentrate