Mineral sands projects use a range of equipment: trucks and excavators, bulldozers, scrapers, monitors and dredges.
Of all the mineral sands that are excavated, the economic minerals account for about 5% of the volume. 95% of the sand is returned to the void.
This means there is no void left behind as happens with a coal or iron ore project. Modern mineral sands projects rehabilitate and backfill voids as they progressively extract the minerals.
Rehabilitation is a continuous process which starts as soon as the excavated material is returned to the void. Topsoil is reapplied and vegetation cover re-seeded or replanted.
Heavy mineral sands are separated from the light sands (mostly quartz and clay) by using gravity processing methods through simple spirals or classifiers.
The concentrated heavy minerals are mixed with water to form a slurry which is pumped to the top of a spiral. As the slurry runs down the spiral, the centrifugal force flings the lighter quartz to the outside edge, leaving the heavy mineral close to the centre of the spiral where it can be collected.
The heavy mineral concentrate or HMC is then containerized ready for transport to downstream processing facilities.
Centrifuges will be used to extract water from fine sand tailings producing a solid cake. The solid cake will be returned to the mine void which is part of the rehabilitation process. Water extracted from the centrifuges will be re-used and recycled.