De Beers Hoovers Up Its Best Diamonds From the African Seabed

For years oil was the big commodity found offshore. These days diamond giant De Beers finds some of its most valuable gems on the Atlantic Ocean seabed off the coast of Namibia.

They are literally vacuuming them off the ocean floor.

The world’s biggest diamond producer has spent $157 million on a state-of-the-art exploration vessel that will scour 6,000 square kilometers (2,300 square miles) of ocean floor for gems, an area about 65 percent bigger than Long Island. The Anglo American Plc unit mines in the area in a 50-50 joint venture with the Namibian government.

The vessel will scan and sample the seabed to identify the most profitable areas for the ships, which suck up diamonds before they’re flown by helicopter to shore. The investment will help the company maintain annual production of at least 1.2 million carats for the next 20 years, Chief Executive Officer Bruce Cleaver said in an interview. Those stones are “very important to our global mix and to our customers who are looking for higher-value diamonds,” Cleaver said.

Namibia’s diamonds, which have been washed down the Orange River from South Africa over millions of years and deposited in the ocean, are key to De Beers because of their high quality. While not the biggest, the gems have few flaws after being broken from larger stones on their way to the sea bed. Only the strong and good quality ones survive, Cleaver said.

De Beers’s Namibian unit sold its diamonds for $528 a carat last year, much higher than the $187 average for the whole company’s stones and accounting for about 13 percent of total earnings.

Photographs by Simon Dawson/Bloomberg

Employees grade rough diamonds using daylight to illuminate the gems at the Namibian Diamond Trading Co. processing and valuation center in Windhoek.

De Beers finds some of its most valuable diamonds on the Atlantic Ocean seabed. 

A high pressure spray cleans discarded non-diamond bearing gravel before being returned to the ocean from the Mafuta mining vessel.

The giant subsea "crawler" tractor is lowered into the ocean from the deck of the Mafuta.

The business end of the giant suction rig begins its descent to the ocean floor.

An enormous sucker pipe brings diamond bearing gravel from the seabed aboard the Mafuta for processing. Up to 60 tonnes of sediment can be lifted every hour.

The Mafuta exploration vessel dredges the seabed at depths of around 150 meters off the Namibian coast. 

A chart detailing the monthly carat production plan and diamond tally aboard the Mafuta. 

A crew member points to a digital monitors showing camera views of mooring systems in the operations room aboard the Mafuta. The vessel positions itself to scan and sample the seabed to identify the most profitable area for the ship to suck up the gems.

Diamonds are dropped by machine into sealed barcoded cans without ever being touched by human hands. A series of vibrating racks and rotating drums crush the sediment into a series of increasingly smaller stones. The whole process is automated.

James Bond-style steel cases are use to ship tins of marine diamonds by helicopter thrice weekly to secure onshore vaults.

Rough diamonds before grading at the Namibian Diamond Trading Co. While not the biggest the maine gems have few flaws. The Orange River deposited the diamonds on the ocean floor from central southern Africa millions of years ago.

Debmarine Nambia's $157 million SS Nujoma diamond exploration and sampling vessel ready for operations following its inauguration at Walvis Bay port, on June 15. Its the most technologically advanced marine mining vessel in the world.

Marine-sourced stones are important to customers looking for higher value diamonds.  De Beers’s Namibian unit sold its diamonds for $528 a carat last year. 

Former open pit diamond mines line the Atlantic shoreline on Namibia's southern Coast.