‘Dredge mining’ is the main method used for obtaining the mineral sands from the Yarraman and Enterprise mines. A very large deep hole is dug out of the island using mining machinery. This hole is then flooded with water and a dredge is floated on this ‘dredge pond’.
The dredge sucks up a sand/water slurry from the bottom of the dredge pond. This slurry is then processed through a floating Mineral Concentrating Plant, extracting the heavy mineral sands.
The sand residue is then dumped at the other end of the dredge pond, and the dredge then ‘eats’ away at the sand to move the whole dredge pond.
See the mining company”s diagram from their Plan of Operations for further detail.
The image on the left shows the Department of Mines” mapping of the ore bodies on North Stradbroke Island, marked in purple. (Mapping for Queensland is available from DME”s interactive mapping website: http://www.dme.qld.gov.au/mines/tenure_maps.cfm )
The image on the right shows the area which will be destroyed if the Enterprise is allowed to continue, the dredge mining will move over the ore body shown in purple on the left.