Diamonds


Namibia is world-renowned for its gem quality placer diamonds that occur along the Orange River as well as, onshore and offshore along the coastline of Namibia (Diamond Map (368KB)) The Namibian diamonds were originally transported via the Orange River into the Atlantic Ocean and distributed northwards by long-shore currents. Diamonds typically occur as placers within raised and “drowned” beach terraces, gullies in the bedrock, and eluvial deposits in wind corridors within southern Namibia. As onshore diamond reserves are depleted, future diamond production will predominately come from the seabed. Mid-water to deep-water mining operations requires sophisticated marine vessels and crawlers that are capable of retrieving diamondiferous gravels/sands from the seafloor. The major diamond producing company in Namibia is Namdeb Diamond Corporation (Pty) Ltd, which accounts for an average of 1.6 million carats per annum. Other companies mining diamonds in Namibia include Sakawe Mining Corporation (Samincor) and Diamond Fields Namibia (Pty) Ltd.
Additional information on diamonds:
Orange River Diamond mining along the Orange River accounts for 5.2% of the total revenue produced by Namdeb and for 2.8% of total carats produced. These diamonds are famous for their good stone size and quality. The Daberas Mine, which is situated on the northern bank of the Orange River some 80 km east of Oranjemund, is mined by the conventional open cast method. The Daberas Mine is the main production facility in the Orange River mining area, and is capable of treating nearly four million tons of diamond-bearing gravel a year.	Mining
On-shore Gem quality diamonds are mined from marine terrace gravels and pocket beaches along Namibia’s coastline from Oranjemund to Luderitz. At present the single biggest source of onshore diamonds is Mining Area 1. The area consists of raised beaches that cover a distance of over 100 km north of the Orange River mouth to Chameis Bay. The 2003 production figure for diamond Mining Area 1 was some 500 000 carats.	Pebble Terrace
At the Elizabeth Bay Mine, situated 25 km south of Luderitz, a new processing plant has recently been constructed. This plant can process previously untreated consolidated marine sediments. This plant will produce some 200 000 carats per year, by processing diamond-bearing material. The project is expected to produce approximately 1.9 million carats over the next eight years.
Off-shore DeBeers Marine, Sakawe Mining Ltd (Samincor), and Diamond Fields Namibia carry out offshore diamond mining in Namibia. Several smaller Black Economic Empowerment (BEE) companies are also involved in small scale contract mining in the surf to shallow water.
Namibian marine diamond recovery has now surpassed traditional land-based diamond production. In 2001, over 60% of Namibia’s app. 1.6 million carats per year came from mining the seabed, with 95% being gem quality. Furthermore, the potential of the marine diamond industry has barely begun to exploit the vast resources of Namibian marine diamonds calculated by experts to contain some 2 billion carats.
Mining Techniques Surf Zone Mining up to a water depth of 15m: Divers operate suction hoses connected to pumps stationed on the beach. The diamondiferous gravels are jigged and diamonds are hand-picked. Shallow Water Mining at water depths from 15m to 20m: Divers sweep the seafloor with suction hoses connected to pumps on small boats. Gravels are concentrated on the boat and taken ashore for sorting. Mid-water mining at water depths from 20m to 100m: Gravels are raised from the ocean floor by an airlift system within solid drill rods (5m-diameter drill bit) to a mining vessel, where they are sorted. The concentrate is taken by helicopter to the sorting house for diamond extraction. Deep-water mining at water depths greater than 100m: A remote-operated mobile seafloor crawler is used, which is connected to the mining vessel by a flexible hose, raising the gravels by airlift. Gravels are sorted on the ship, and the concentrate is taken to diamond hand picking on land.
Kimberlites Active exploration for diamondiferous kimberlite pipes is ongoing in northeastern Namibia, where kimberlite indicator minerals (e.g. ilmenite, garnet, chrom-diopside) as well as micro-diamonds have been recovered. Companies exploring for diamondiferous kimberlites include Motapa Diamonds Incorporation, Mount Burgess Mining N.L and DeBeers. Past exploration of kimberlite pipes within the Gibeon Kimberlite Province was unable to delineate diamondiferous kimberlites due to their off-craton setting. To date, no economic diamondiferous kimberlite pipes have been discovered, but great potential exists on both the Congo and Kalahari cratons.
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