Have you ever been to a diamond mine? Depending on the type of diamond mine in question, these feats of man are a sight to behold. The open-pit mining method, particularly the underground tunnelling variant, is a magnificent (or monstrous) effort: the sheer scope and scale of these projects make one ponder the reality of diamonds: their value, their rarity, and underlying it, the trouble humans go through to get this hardened structure of carbon into the hands of those who are able to afford them. One of the reasons why diamonds are so valuable is due to the complex and challenging process that goes into bringing these gemstones, many of them found in regions that stretch for hundreds of meters underground, to the market. One must also consider the variety of diamond mining processes. For in addition to the open-pit method, there are the alluvial mining and the more interesting, and arguably more complex, marine mining method. Also, it is worth keeping in mind there is a lot of jargon that gets used when it comes to the mining of minerals, especially diamonds. Given the variety of the various mining methods and in some cases the overlapping character of certain methods, confusions could arise. Just be aware that the fundamental differences lie in the techniques, type of areas mined and scope of the diamond mining projects.
Open-pit/Surface Mining Method
The type of diamond mining method that Characterized by its vastness which exemplifies the complexity of diamond mining. Open-pit mining also referred to as opencast mining, is a mining method where precious minerals are extracted from an open pit in the ground. Surface or open-pit mining is arguably the most commonly used method used for the mining of, not only diamonds but also other valuable minerals. Owing to its relative simplicity, this process does not involve expansive extractive methods: such as the use of vast underground tunnels, and the infrastructure that needs to be built to support it. The surface mining method is used when mineral deposits are found relatively close to the surface of the Earth. However, that does mean simply digging a relatively large hole in the ground will get you close to the location of precious stones. Diamonds, which are formed over billions of years kilometres underground, and found with ore and around other types of mineral and stone deposits. Hence unearthing them often, even at a higher surface level, requires first the breaking down (at times via explosives) of the core deposits in which they are found.
Prior to the start of these projects, diamond miners employ experts to survey potential diamond sources: a process known as prospecting: Where the geological character of the select diamond mining, region is studied for its chemical and mineral character. Once a viable location is identified the mining process begins. Open-pit mines are dug in a variety of locations, and they could go for several meters in depth. With the width of the pit going from a few meters to a few dozen, depending on the size of the planned project. When the process of digging gets underway, miners take care to ensure the walls of open-pit mines are dug at an angle, in a step-like formation. Which is done to prevent avalanches that may occur owing to a greater level of steepness. The inclined section of the wall that surrounds the pit enables ease of access for personnel and equipment. Once the diamond deposits are collected, they need to transport back to the surface, which to involves a relatively complex process.
This is a variant of the open-pit mining method. As the name implies, underground mining involves the mining company using heavy equipment to bore deep down into the Earth’s surface, reaching levels that take it closer to Earth’s crust, where potential diamonds deposits are identified. Underground mining is the next level in the open-pit mining process: in that, once the diamonds found at higher levels are taken, miners proceed deeper into the Earth surface. Given the complexity of the undertaking, considerable effort is put into ensuring the economic viability of the project. For prior to the establishment of diamond mining pits, and the vast logistical operation that surrounds it, considerable research goes into it ensuring the safety and long term potential of such an undertaking. This requires the study of the select region, the scientific surveys to verify its resource potential and the cost factor that underlies it, and the potential pay off the company, investors etc Why is this necessary one may ask? To answer, one must understand how diamonds emerge.
Role of Kimberlite
Diamonds are considered precious stones for a reason. As noted, these gems form over billions of years and are found hundreds of kilometres under the Earth’s surface. These hardened carbon minerals are then bought to the surface through complex volcanic processes, involving a certain volcanic rock type known as kimberlite (there is another variant known as lamproite). Whilst the kimberlite is not itself responsible for the formation of diamonds, it is the key vehicle that brings, via the volcanic process, these precious stones to a higher, more accessible level. So the trick for the diamond mining company is in locating the kimberlite pipes: vertical structures where these type of rock formations are found. Kimberlite formations that contain diamond deposits (known as Diamondiferous) are the key determinant for finding and establishing an economically viable diamond mining operation.
Alluvial Mining Method
Alluvial mining takes place where diamonds have moved from their primary kimberlite pipes, owing to environmental factors, over a long period. Water, nontaxable water caused erosion is the key driver that helps breakdown the surface around the diamond deposits from its original source. Alluvium, which refers to loose soil or sediment that has been broken down by water over a long period is deposited in which diamonds are found. Since water always flows down: moving from higher elevation to lower levels, the diamond deposits invariably wash down to water-rich natural environments: like river beds and ocean shores. Once a potential diamond source has been located, the industrial process unfolds. The process usually involved diamond-bearing sediment located near the specific source, being moved to the designated facilities. Where the next stage of the washing, separating process beings. The screening for diamonds is a technical process, involving various stages, where the stones that are diamond potential, are sent to a plant to be washed and screened for diamonds. A variant of this can be offshore diamond mining operations, owing to their closeness to water. However owing to the different environment and the type of machines that are used, this diamond mining methods fall into a separate category.
Marine Mining Method
Offshore mining is a complex process. Like with anything that involves the sea and deep waters, this process involves the use of ships and other vessels that are used to locate, and mine for these gemstones that lie within the seabed. A process, from surveying to dredging, that has constantly changed over the years with the changes in technology. For much of the initial work goes into identifying and setting up a viable diamond mining spot is a process that is aided by personnel in underwater vehicles, or in more recent times with the aid of unmanned machines. Once the correct spot is located, designed vessels are commissioned to carry out the dredging process. Where tones of sediment are taken of the seabed with the aid of giant pipes. Once the potentially diamond-rich sediment is collected, the separating process begins. Depending on the vessel, this often takes place onboard the ship. Where the sediment is sifted to isolate smaller stones. Various techniques are used to separate out the stones that are potentially diamond-bearing from the rest. Once the potential stones are isolated, the sediments are sent back to the original location within the sea bed. With the potentially diamond-rich rocks and stones sent to factors on land for further inspection and improvement.