Diamonds are a sought after precious stone that are included in many pieces of beautiful jewelry. They are the hardest known substance on the earth and come in a variety of different grades, colors and sizes. This mineral is used in both the jewelry industry and the industrial industry for cutting and polishing. Perfect natural diamonds with no impurities are clear in color. Those that are colored contain other elements such as boron or nitrogen. Diamonds from below the surface and therefore need to be mined from beneath the ground.
There are two ways that diamonds are mined from underground, these are: pipe mining and alluvial mining. Pipe mining is where diamonds are extracted from the earth via volcanic pipes. These pipes are geologically formed by the flow of magma from the earth’s core to the earth’s crust. When a pipe is discovered shanks are driven into the ground around the outside edge. Most diamond pip mines consist of Kimberlite. This Kimberlite is dug from the ground. Once the top layer has been mined and the deposits exhausted, tunnels are dug to extract the ore from below the surface. Large pieces of rock containing diamonds are mined and sent to a screening plant where they are sorted and the diamonds separated from the rock.
Alluvial mining is where diamonds are extracted from riverbeds or beaches. It involves large walls being built to hold back the water so that the ground can be accessed underneath. The sand in the riverbed or on the beach is bulldozed out of the way until the earth where the diamonds can be found is reached. This is usually a gravelly layer found at least 25 meters under the sand. This gravel is then dug out using bulldozers and transported to the screening plant for processing.
Diamonds can also be found in a similar way to gold. Many diamonds that are mined in poorer countries are sieved out of the mud and sediment in rivers and creeks, much the same way that gold is panned for.