Marine minerals: Their occurrences, exploration and exploitation

Earth´s oceans and seas, covering 71% of the planet, harbor a myriad of mineral resources both near-shore and at great depths. At present, the only significant commercial exploitation is in shallow water and on beaches for aggregates, diamonds, tin and salt together with minor recovery of heavy minerals containing chromium, rare earths, thorium, titanium and zirconium; lime from coral and shells; and some artisanal recovery of placer gold. There are opportunities for expanding all of these activities. The deep sea holds resources up to several thousand meters water depth of copper, nickel and cobalt in manganese nodules; cobalt, nickel, platinum group metals and rare earth elements in ferromanganese crusts on seamounts; copper, zinc, lead, silver and gold in seafloor massive sulfides (SMS) and seafloor sedimentary sulfides (SSS); and recently discovered rare earth elements with Yttrium in deep-sea mud. Except in a few cases where on-land resources are waning such as for phosphate, ocean mining will not replace mining on land but will provide an additional source of raw materials required for rapidly expanding economies in the developing world.