De Beers planning big offshore diamond mining programme in South Africa

De Beers planning big offshore diamond mining programme in South Africa

De Beers, is currently fitting out its largest marine mining vessel in Cape Town for a programme to mine marine diamonds south of the mouth of the Orange River in South Africa. Hitherto most of De Beers’ offshore diamond mining has been undertaken on the Nambian side of the border, north of the Orange River.

The new vessel, named Peace in Africa, and associated mining and processing plant is costing the company R1.1 billion (US$153 million) and fitting out is due for completion, and sea trials run, by July 13th. First production is expected in August this year.

The project, known as SASA (South African Sea Areas) is considered necessary by De Beers to replace output from its declining South African land-based operations and is considered vital for maintaining output there. As experience is gained with the mining system and its results, the company will consider adding further vessels of this type to its fleet.

The marine vessel is an impressive one, incorporating a huge gantry at the bow end for launching the mining crawler unit which will work the seabed, and a complete Bateman-designed process plant with a capacity to handle 10,000 cubic metres an hour of material pumped up from the crawler working the seabed.

The concession area to be worked by the new vessel and seabed crawler unit is some 8,000 square kilometres and production of 240,000 carats a month of diamonds is anticipated. The 260 ton seabed crawler unit, which undertakes the actual mining, is connected to the ship by a 650 mm internal diameter umbilical through which the seabed material is pumped to the plant using a 2MW pumping system.

The ship and crawler will work up to 35 km offshore and at depths of up to 200 metres. Mining will be undertaken in 100m x 500m blocks.

It is anticipated that the vessel will remain at sea continuously for 2 ½ years before returning to port for a refit. The crew works on board for 28 days (12 hours on, 12 hours off) followed by 28 days leave and is flown in and out by helicopter in a similar pattern to that for offshore oil rigs.


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