Crown

Crown is the world’s largest gold surface tailings retreatment facility, reprocessing the large and numerous sand and slimes dumps along the reefs that stretch from east to west just to the south of Johannesburg’s central business district (CBD). Most of these dumps hold waste from the stamp milling era of ore processing when plants treated the sand and slimes separately, unlike current milling methods which reduce all ore to slimes before the extraction of gold.

The dumps are reclaimed and mixed with water. The slurry is then pumped to one of Crown’s three processing plants: Crown Mines, 3km to the south, City Deep, 6km to the south-east, and Knights, 20km to the east of Johannesburg’s CBD. Using relatively modern milling methods and carbon-in-pulp (CIP) technology, these plants have the capacity to treat 11.76Mt of sand and tailings a year. The land that is uncovered through removing the tailings is reclaimed and developed mainly for light industrial activities.

Crown’s current major project is Top Star, a tailings dam to the south of Johannesburg’s CBD. Throughput from this 126 000oz resource (93 000oz attributable) is at a rate of 100 000tpm with an average head grade of 0.775g/t and a cost of R61/t. A new, 50km pipeline currently under construction and scheduled for completion by August 2011, will link two of Crown’s plants with Ergo. This will provide Crown with increased tailings deposition capacity – a constraint in recent times – and thus the potential to extend its life by bringing to account further surface tailings resources on the western and central Witwatersrand. In October 2010, DRDGOLD announced that its 74%-owned subsidiary, DRDGOLD SA, had successfully raised R108 million towards the R300 million capital cost of the pipeline through a Medium Term Note Programme.

During the fourth quarter of FY2010, the surface circuit of ERPM was incorporated into Crown.

Crown layout plan