Most natural diamonds on Earth formed millions of years ago in the Earth’s mantle. Today, they remain under the surface of the ground, just waiting to be found. But how do we get them out? Diamond mining is a big business, and as it turns out, there are plenty of different ways to build a diamond mine. Diamonds are mined from the ground, out of rivers, and even from under the sea, and miners use different tactics when setting up a diamond mine. So how exactly do you go about building one?
Open-pit and underground mining
This is probably what you see in your head when you hear the words “diamond mine”.
Open-pit mining is used when the diamonds are pretty close to the surface. This kind of mine is also useful for when it’s too dangerous to go underground. Open-pit mines are dug in layers, with each layer going deeper into the earth. The area that the mine covers can be huge, especially when looking for deposits of a specific mineral such as diamonds. Take, for instance, the Orapa diamond mine in Botswana, the largest diamond mine in the world. The mine covers almost half a square mile on the surface and is over 1,000 feet deep!
The other kind of mine that you probably envision when talking about mining is an underground mine. Underground mines are built when the diamonds are deeper below the surface. They work by digging a shaft, or tunnel, downward until you are deep enough to get to the resources. From there tunnels are built away from the shaft to get to whatever is being mined. Usually, underground mines are so deep that the ground is rocky and hard, so workers use explosives to dig tunnels.
The word “alluvial” means “deposited by running water”. Alluvial mines are built near bodies of water, whether that’s the coastline or something inland, like a lake or river. Alluvial mines take advantage of water naturally carrying and depositing minerals into underwater beds by mining at the deposit. A simple example of alluvial mining is prospecting for gold, which happened a lot during the American gold rush. A large-scale alluvial diamond mine works a little differently, though. Alluvial mines will often divert water away from the deposit by building walls to cut the water off. After separating the area from the water, miners can safely dig out the deposit and take it somewhere else to be sorted.
Marine mining happens when the diamonds are in the ocean floor. Unlike a traditional mine, you can’t build a marine mine on site. Rather, ships with special mining equipment sail over the mining area to find out which areas to mine. After that, a seafloor crawler dredges the seabed, cutting into the earth and loosens the deposit. Finally, the ship sails over one more time, this time dragging a massive tube along the dredged area to suck up all the soil. Once onboard, machines remove the diamonds and return the leftover sediment to the ocean floor.
Informal diamond mining
Remember how I talked about people panning for gold during the gold rush? Turns out, people still do that, but with diamonds. But think about the last time you saw people mining for diamonds in America. Can’t think of it? That’s because we don’t do it here anymore. Informal diamond mining, also called artisanal mining, mostly happens in Africa and South America. Artisanal mining is a cover-all term to describe people digging for diamonds with simple tools, and often entire communities work sifting through gravel in rivers and streams to find the sought-after gems. Surprisingly, artisanal mining supplies an estimated 15-20% of the world’s gem-quality diamonds.
Negative impacts of a diamond mine
The environmental impact of a diamond mine depends a lot on the choices of the company that built the mine. To their credit, many mining companies do what they can to keep the operation eco-friendly, and marine mining leaves behind a relatively small impact. However, if not managed carefully, open-pit mining and alluvial mining can be devastating. Mining pits completely strip away the upper layers, destroying anything that once lived there, and water can pool into them. Alluvial mines run the risk of diverting water to places it doesn’t belong, as well as contaminating the water in the process.
Then there’s the human cost of mining. Open-pit miners avoid threats such as dust, fire, and debris. For workers in an underground mine, cave-ins, explosions, and gas leaks are serious risks. The worst damage, though, comes from artisanal mining. Workers at these mines face health conditions from working long hours in stagnant water. Often these mining operations are illegal, and the miners live in deep, cyclical poverty.
On top of all that, illegal diamond mining is a lucrative option for supporting ongoing conflicts in developing countries, giving diamonds produced by it the name “conflict diamonds” or “blood diamonds”.
Despite the precautions mining companies take, because of the impact that diamond mines have on the local area, many people look elsewhere for jewelry sources. One such alternative is synthetic diamonds. Synthetic diamonds have the same properties as real diamonds, are made in labs instead of being mined from the earth, and even cost less than traditional diamonds! Synthetic diamonds are still a relatively new invention. Only recently have they become affordable and producible enough to be a good option for jewelry. If you want to find out more, feel free to read my previous post that talks about them in detail. In any case, now that you know about where diamonds come from, you can make a more informed decision on what to choose for the most important ring you’ll ever buy!