There are two main kimberlite varieties, as well as examples of late-stage internal dykes.

It is recognized three varieties of kimberlite in the main pipe, which he named KOF1-3. These comprised two diatreme-facies (KOF1 and 2) and
a hypabyssalfacies kimberlite (KOF3). The KOF-1 variety was a TKB that occupied the main pipe, whereas KOF-2 was a TKB that occupied the “West Fissure”. The KOF-3 variety was the hypabyssal intrusion that occurred as the “East Fissure”. A further notable feature was the presence of a large floating reef comprising various Karoo lithologies in the main pipe. A satellite kimberlite pipe named Ebenhaezer, which also contained diatreme-facies kimberlite, is located close to the main pipe.

The kimberlite between the floating reef and the eastern contact at depth to be geochemically distinct from the main kimberlite variety that had been mined throughout the life of the mine.

Sub-level / Block Cave

Mine Plan to 2027

+20yr Potential Life

Typically, the washed material can be further processed using a method known as dense media separation (DMS). DMS uses fine ferro-silicon powder (an alloy of iron and silicone) suspended in water to form a fluid near the density of diamond. The diamond bearing material is added to this mixture. The material that is lighter than the mixture (this includes the diamonds) would float and then move on to the next level. The material that is heavier sinks to the bottom and is discarded.