Diamond mining around the world is done in one of two common methods: Pipe Mining and Alluvial Mining. Pipe mining is the process of removing diamonds from volcanic pipes, which are the result of volcanic eruptions and lava flowing towards the surface. Long shafts are dug along the surface of volcanic pipes, and the removed soil is sent to the surface for processing. This type of mining is extremely inefficient, yielding only a one carat gem-quality diamond for every 250 tons of ore mined from the pipes.
Although diamonds found through alluvial mining were once in volcanic pipes, over time these diamonds became dislocated and were carried off into streams, rivers, and even oceans. In order to harvest these diamonds, large tracts of land are bulldozed and machines dig down over 75 feet to reach the layer of soil containing diamonds. Mass quantities of soil from this layer are extracted and sent to screening facilities in order to reveal the diamonds. Alluvial mining is only slightly more efficient than pipe mining.
The cost of diamonds is a reflection of their rarity and the cost required to extract them. Neither process is environmentally friendly, nor are diamond companies always in the cross hairs of environmental groups because of their controversial methods. Diamond mining companies have also been frequently used as scapegoats for political instability in African. These issues seem to have little to no effect on peoples’ willingness to buy diamonds, as prices continue to rise and more mining operations are opened on a yearly basis.