Thanks to the development of innovative technology that finally evolved in the 1990s to commercial-scale usability, there’s a new way to obtain diamonds today. This doesn’t involve synthetically creating diamonds, or extracting diamonds from deeper land mass sources. Diamonds are now coming from marine sources at both shallow and deep depths.

Types of Marine Diamond Mining

Marine mining makes use of two types of techniques that serve to extract diamond from placer deposits located at sea: vertical and horizontal. Both techniques are intriguing, and each has advantages depending on the location of the diamonds offshore.
With vertical mining, special equipment is used to drill into the seabed. This involves using a drill bit that is six or seven meters in diameter. After the surface is drilled, material containing diamonds is then sucked up from the floor of the sea.

Marine Mining at Different Depths

Horizontal marine mining makes use of remote controlled underwater mining vehicles called Seabed Crawlers. In this mining technique, material on the seafloor that contains diamonds is pumped up to offshore mining dredging vessels through hoses that attach the Seabed Crawlers to ships. The material from the seabed is then sorted through on the vessels. Gravel containing diamonds is transferred to land for further hand sorting.

Sea Crawlers are used for deep-sea diamond mining at depths of 100m or more. At shallower water depths up to 15m in mining areas along the shore, divers suction the sea bottom with hoses. The gravel and other materials are jigged and diamonds are handpicked.

At depths of 15 to 20m, divers may use suction hoses that enable gravel to be pumped onboard ships. At these depths, pumps on small boats are all that is needed to raise the seabed materials to the vessels. In the case of mid-range marine mining at 20 to 100m depths, 5m diameter drill bits are used, and materials are raised by airlift systems as in deep-sea operations.

Marine Mining off the coast of Namibia

One very popular place for marine diamond mining is off the coast of Namibia along Africa’s southern Atlantic shore. Namibia’s shoreline is world renowned as a deposit of gem quality diamonds that have a unique history. These diamonds actually traveled to the sea along rivers from a distance approximately 1,000 kilometers inland. Their rough journey over such an incredible distance resulted in a diamond deposit that is 95% gem quality.

Today, more diamonds are recovered from marine mining in Namibia than land-based mining. Experts estimate Namibia’s marine diamond resources contain up to 2 billion carats.

A Surprise Discovery for Australian Marine Miners

Australia-based Bonaparte Diamond Mines is currently involved in marine diamond mining operations off the coast of Namibia. This is one of only a few of the world’s diamond mining operators, and the only one from Australia. In addition to diamonds, Bonaparte made a unique discovery off Namibia’s shores during diamond mining research and operations.

Bonaparte discovered rich deposits of marine phosphates along the coast of Namibia. Though not as precious as diamonds, marine phosphates are also valuable. Marine phosphates are used to make some types of fertilizers. It wasn’t a complete surprise to Bonaparte, but it is an important commodity the company is obviously excited about.

Dredging for phosphates offshore is not new, according to a Bonaparte spokesperson, and is practiced around the world in places such as Singapore and Dubai. Marine phosphate dredging practices were perfected by the Dutch and Belgians decades ago.

Experience and Environmental Impact

Part of the reason for the emphasis on the fact that marine phosphate dredging is not new is related to concerns about environmental impact. Although Bonaparte insists the processes are extremely well understood, dredging is often a controversial practice.

Namibia may be at a distinct advantage in terms of the environmental impact both diamond mining and dredging may have due to their own experience. Marine diamond mining is an established industry in Namibia as it is in few other places in the world. Legislation oversees marine mining there, and management programs are already in place. Companies such as Bonaparte must work within marine mining guidelines established by Namibia’s government.

In marine diamond mining, practices often involve the replacement of a large amount of the material that is removed from the sea floor in the same location shortly after extraction. In cases of surface scraping, rehabilitation efforts can be used to help facilitate natural regeneration.

Time will tell whether the environmental impacts of marine diamond mining off the coast of Namibia will prove to be minimal and manageable or have lasting, significant effects. It is encouraging that some measures are in place to protect the environment as new discoveries continue to raise the stakes regarding the value of the natural resources in this unique area.

Other articles of interest:

• Growth in Diamond Export and Import
• Chinese Diamond Industry is Shining Bright
• Australia could be the Site of the Next Big Diamond Rush
• Environmental Awareness in the Diamond Mining Industry