If you live in the United States, where the most diamond jewelry is bought every year, that diamond engagement or wedding ring that you wear probably features a diamond that did NOT come from the U.S. At the time of this writing there are no commercial diamond mines operating in the U.S. The last one that there was so far, the Kelsey Lake Mine situated close to the Colorado-Wyoming border, shut down operations in April of 2002. The most valuable diamond that site ever yielded was worth $300,000. Today, there is one non-commercial (that is, unowned by any private company) diamond mining site in operation in the U.S.: Crater of Diamonds State Park in Arkansas. This operates on a fee-to-mine basis. There have been many famous diamond discoveries at this location throughout the decades, including the 40.23 carat Uncle Same diamond discovered at the Park in 1924. In 1990, Shirley Strawn uncovered a 3.09 carat diamond that got cut to 1.09 carats in 1997 and received a “perfect” grade of 0/0/0 by the American Gem Society in 1998, making it the first diamond ever given this mind-blowing AGS grading. Now this diamond is on display in the state park.
However, some diamond mining companies are interested in Alaska, Wyoming, and Minnesota as potential diamond repositories.
The following are the world’s currently active commercial diamond mine locations:
Angola (three mines)
South Africa (eight)
Diamonds are mined in different ways, taking into consideration how the minerals are deposited, how stable the surrounding terrain is, and what environmentally disruptive impact mining would have.
Artisinal mining is also called small-scale mining. This is what is typically used in poor areas and the people who do the mining are called “diamond diggers” who use their hands and very basic tools like shovels and sieves to find diamonds. These diamond diggers are considered “subsistence-level” workers and are most often, but not exclusively, found in Africa.
Hard rock mining involves creating underground diamond mines featuring “stopes”, or underground rooms that are supported by natural underground pillars. This type of diamond minding involves the creation of “declines” (shafts) and is achieved through a combination of manpower and advanced machinery.
Marine mining is a relatively new form of diamond mining which hasn’t even been around for 20 years yet. Offshore placer deposits are mined for diamonds; huge drills up to seven meters in diameter are used to drill down into the seabed and suck up the underwater material that contains the diamonds. Remote-controlled Seabed Crawlers are also used to move horizontally along the sea floor; they pump prospective gravel up to a ship.
Open pit mining is used when the surface material, or “overburden”, that covers the diamond deposits is thin and prospectors find diamonds or what are called kimberlite pipes near or on the surface of an area. A pit is dug and diamonds are extracted from it.
If diamonds are found within alluvial, colluvial, or eluvial secondary deposits, Placer Mining is used for extracting them. Hydraulic, mechanized, or artisinal mining techniques may be used for extraction.
Isn’t it fascinating to know more about where that diamond you love might have come from and how it got to you? Knowledge makes your gem even more valuable to you.