MARINE DIAMONDS

Much publicity of late has been devoted to the new marine method of extraction of diamond. This has not proved very profitable, however. In connection with marine terraces and with river-bed sources, it was evident that such sources did not automatically stop at coast-lines; there must be some diamondiferous-bearing gravel off-shore on the sea-bed itself. Such marine diamond 'fields' have been sought out and are being worked. Special ships have been designed and built. Huge suction pumps have been installed, and the gravel front the sea-bed is sucked up, sorted through and then discharged some distance away in order not to foul the region being worked.
There are great difficulties in the way. Only in calm weather can the great suction tubes be trailed on the sea bottom. The depth to be 'fished' is limited by the weight of the suction tube. The tubes are constantly jamming through being blocked by large boulders loosened in the operation. The results of the sea mining are disappointing in terms of the costs of the operations. Diamonds are certainly recovered, as predicted, but the volume acquired makes the operation work at a loss, In spite of this, the method is being pursued doggedly.