 | De Beers is searching for diamonds in deeper water off Namibia’s coast as a result of technological advances that it has led which have enabled it to create enormous mud-sifting machinery. A crawling machine weighing close to 300 tonnes and three stories high recovers diamonds by vacuuming up sand and silt at a depth of 100 metres. |  |
 | Offshore diamond mining started 50 years ago at depths of less than 35 meters, but technological developments in the past decade have allowed operations in deeper water. Ten years ago a crawler would be mining at about 200 to 250 square meters an hour. Today the crawler would mine at about 1,000 square meters an hour. |  |
 | The crawlers have made a step-change in mining and productivity of marine mining. When the sea bed becomes too rocky and uneven for the giant vacuum, the firm can switch to "vertical mining" by four other ships, which each use a large-diameter drill to bring diamond-bearing gravel to the surface. |  |
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