Diamond Mining

               Of all the diamonds mined in the world each year, less than half are gem quality; the rest fall into two other main categories known as near-gem quality and industrial quality diamonds.
Gem quality diamonds display a high standard of excellence in quality and are used in diamond rings and other diamond jewelry. The clarity of these loose diamonds ranges from flawless through to visible inclusions.
Near-gem quality diamonds represent those stones of a quality between gem and industrial that in fact can be used as either depending on the individual stone. These stones have clarity grades ranging from visible inclusions through to industrial.
Industrial quality diamonds are low quality or badly included stones and are suitable only for industrial use; for example, they are used in dentist's drills and earth moving equipment.

Diamonds are recovered by way of pipe or alluvial mining.

Pipe Mining

Pipe mining refers to the extraction of diamonds from volcanic pipes. Typically, a very large area has to be covered. An average of 250 tons of ore must be mined in order to produce a one-carat gem quality polished diamond.

In most countries, a diamond pipe mine is composed of kimberlite, or blue ground. Initially kimberlite is dug from the surface of the pipes in rough opencast mining. Once the surface deposits have been exhausted, shafts are sunk into the ground at the edge of the pipes, and tunnels are driven into the deeper parts of the pipes.

Open Cut Mining

In open cut mining, the ore is dislodged by blasting and then loaded by excavators into 120-ton dump trucks. The ore is then transported to the processing plant where the diamonds are extracted. The processing techniques are purely physical and involve crushing, scrubbing, screening and gravity separation of the diamond-bearing ore. Final diamond recovery is achieved by the use of x-ray sorting machines. The machines can detect and remove diamond material because the diamonds fluoresce under x-ray.