Metal-bearing deposits on the deep-sea floor, consisting of nodules, crusts, and accumulations of metallic sulfides from deep vents, are of potential economic interest. In the 1970s and ’80s it was hoped that mining the nodules—which contain quantities of manganese, iron, copper, nickel, titanium, and cobalt, as well as small traces of other metals—might be a way to contribute to the wealth of newly industrializing countries. Economic considerations and concern over management of mining operations, however, have slowed exploration and development of underwater mining technology. Marine sulfide ores, containing iron, copper, cobalt, zinc, and traces of other metallic elements, are deposited ...(100 of 7311 words)