The Tedagua/Cobra team in Chile has achieved a major milestone in the project to supply desalinated water to the Spence Mine (Spence Growth Option – SGO) by commencing full-capacity operation and production at the plant, and delivering a nominal flow of 86,400 m3/day. The SGO project, owned by BHP Billiton, is one of the most ambitious projects being carried out in the Antofagasta Region with planned investment of more than 2.46 billion dollars.
The desalination plant is a vital part of the project, as it produces the water necessary for copper ore concentration and subsequent refining processes. Once the seawater has been desalinated, it is conveyed by means of three pumps through a 154-kilometre pipeline to the mine, located at 1,651 metres above sea level.
The product water is obtained through the implementation of reverse osmosis technology. Prior to this process, a number of pretreatments are carried out, including screening, organic matter removal by means of dissolved air floatation, two-stage filtration with multimedia beds and cartridge filtration. Once the desalination process has been completed, the water obtained is remineralised by means of calcite beds and its composition is adjusted to make it suitable for its intended use.
This plant is particularly important for a region with very intensive copper mining activity. The use of desalinated water in the processes of obtaining minerals makes water resources more sustainable, avoids the use of fresh surface water or groundwater resources, which are extremely scarce in the area, and initiates a new, more environmentally-friendly economic model.