1S2 



Submerged placer deposits may be a more 

 promising source of minerals. These deposits, 

 accumulated in the past ages by the effects 

 of bottom topography, offshore currents, and 

 beach and alluvial processes, are confined 

 mainly to the inner edge of the continental 

 shelf. It is unlikely that significant placer 

 deposits will lie found on the continental 

 slope or beyond. Sand and gravel deposits 

 are now being utilized for commercial pro- 

 duction in the T'^^nited States. Serious inves- 

 tigation is warranted of the prospects for 

 commercial utilization of the placers, par- 

 ticularly gold, platinum, and chromite on the 

 west coast (including Alaska) and phos- 

 phorite, ilmenite, and zircon on the east 

 coast. 



Another source of minerals is the subbot- 

 tom, including the substrata of the conti- 

 nental shelves and slopes from which oil, gas, 

 and sulfur are recovered. The seabed also may 

 yield coal, potash, phosphatic rock, iron ore, 

 bauxite, and possibly metallic vein deposits. 



Coal has been mined (working from on- 

 shore shafts or artificial islands) off the coasts 

 of Canada, the Ignited Kingdom, Japan, and 

 Taiwan. Commercial grades of iron ore have 

 been mined to a much lesser extent off New- 

 foundland and Finland. Onshore lode or bed- 

 rock deposits are sufficiently abundant near 

 the shoreline in Alaska, the west coast, and 

 New England to suggest the presence of oft'- 

 shore deposits of similar character in rock 

 formations of the continental shelf. Very 

 little is known about the potential of buried 

 consolidated rock deposits in the seabed. TTn- 

 less accessible from onshore sites or artificial 

 islands, exploitation of these deposits pre- 

 sents formidable problems and thus lies well 

 into the future. 



Beyond the continental slopes, the only de- 

 posits currently seeming to have potential 

 economic importance are nodules, crusts, and 



oozes. The nodules have stirred active com- 

 mercial interest, not only because of the 

 manganese content but also because they con- 

 tain significant amounts of copper, cobalt, 

 and nickel. The rocks beneath the abyssal 

 ocean floor remain far beyond our present 

 technical capacity to explore. They are 

 thought to contain minerals associated with 

 basic and ultrabasic rocks of igneous origin, 

 such as chromite and nickel. 



The discovery of rich brines in depressions 

 on the floor of the Red Sea may indicate 

 another source of exploitable minerals. It has 

 been speculated that similar brines may occur 

 elsewhere. 



The State of Ocean Mining 



The marine mining industry is in its in- 

 fancy. Exclusive of oil and gas, the total 

 1967 value of offshore world mineral produc- 

 tion was estimated at nearly $1 billion, of 

 which about 20 per cent came from U.S. 

 waters. However, about 35 per cent of the 

 world total was accounted for by coal re- 

 covered through tunnels from the shore, and 

 about 40 per cent was chemicals recovered 

 from the sea water column. Worldwide, less 

 than $200 million worth of mineral products 

 was mined directly from the ocean floor an- 

 nually. If common sand, gravel, oyster shells, 

 and sulfur are excluded, this figure reduces 

 to $50 million, which is the present annual 

 world value of tin, iron, heavy minerals, and 

 diamond production from offshore sources. 



"Worldwide, there were in 1967 approxi- 

 mately oOO marine mining operations of all 

 types. All of these operations were nearshore, 

 and almost all such operations involving pro- 

 duction of hard minerals from tlie ocean floor 

 are based abroad. 



Although the record of actual exploitation 

 is relatively modest. Government agencies 

 and a fairly large number of private firms 

 are engaged increasingly in exploration and 



