Marine Diamond Mining
The near-shore and shelf environments of the Benguela Current region hold rich reserves of minerals, particularly diamonds.
Namibia has the richest marine diamond deposits in the world, with an estimated reserve of over 1.5 billion carats. All of these deposits are secondary, with the diamonds originally being sourced from kimberlites in South Africa, transported via the Orange River and deposited along the coastlines of Namibia and South Africa.
In 2005, Namibian production from onshore, beach and marine sources totaled 1.8 million carats, compared with the 1.7 million carats produced in 2003. Of this, marine production reached a record 56 percent of Namibia's total diamond production.
Offshore diamond mining concessions extend along the full length of the Namibian coastline, from the Orange River in the south to the Kunene River in the north. Namdeb Diamond Company, an equal partnership between De Beers and the Namibian government is the country's main producer.
The considerable potential of Namibia's marine deposits has resulted in rapid advances in marine diamond extraction technology. Modern deepwater mining methods involve the use of drill systems or seabed crawlers. Both systems loosen and remove unconsolidated seabed sediments which are then airlifted or pumped to a dynamically moored vessel for processing.
South Africa's diamond production totaled 15.8 million carats in 2005. A total of 126 mining and prospecting licensees produced diamonds in 2005, of which 18 mined kimberlites, 90 exploited alluvial deposits and only 18 recovered diamonds from the marine environment. The Trans Hex Group and Alexkor dominate the marine mining sector in South Africa.
In 2005, marine diamond production declined sharply to about 56 000 carats from 105 000 carats in 2004. However, De Beers has committed USD118-million to equip a high-tech ship for the South African Sea Areas marine mining project.