Separation of the heavy mineral concentrate (mostly ilmenite and zircon) from sand is done using wet cyclones and requires large volumes of water (about 2ML per day - about the volume of an Olympic swimming pool). This water is initially obtained from layers of ground-water bearing rocks called aquifers, 600m below the mine. Sometimes surface water is also used. The water is washed down through the spiral cyclones to separate the heavy and light minerals. It then passes to a settling tank, where clay and sand can settle out for recycling through the cyclone plant.
The settling tank with the heavy mineral concentrate stockpile in the background.
The water then flows to a retention pond, from where it is reused in the cyclones. In this way, a minimum amount of water needs to be extracted from the aquifer. In fact, about 88% of the water is recycled ? most of the remainder is lost by evaporation from the retention pond.
This retention pond contains water for recycling through the cyclones.
Water used for washing down the plant or mine vehicles is recycled, rather than being allowed to simply soak into the ground and be wasted. Washing of equipment is performed on concrete aprons, which have drains that allow the water to flow back into the retention pond, from where it can be re-used. This also prevents any contaminated water from entering the environment.
This mine worker is hosing the concrete apron under the processing plant, to clean it. The water flows via a drain into a retention pond from where it is recycled.
