DIAMOND MINING

Open pit diamond mining, is done using the surface mining technique. The surrounding earth and rocks are removed to expose the underlying kimberlite, the ore which contains the diamonds. The process is known as "waste stripping".

The ore is blasted and loaded into trucks, hauled to a crusher, reduced in size and conveyed to a primary stockpile. Crushed ore is then conveyed to a treatment plant for processing.

DIAMOND RECOVERY

Inside the treatment plant, the kimberlite is further crushed, washed and screened into different size fractions. Dense-medium separation is used to produce a diamondiferous concentrate, which is then subject to X-ray fluorescence sorting to separate diamonds from residual waste.

After drying, final hand-sorting recovers the diamonds, which are sent to the offices of the Central Selling Organisation (CSO) in Kimberley for classification. There are some 5,000 categories based on combinations of size, shape, colour and the quality of the diamonds recovered.