ABSTRACT
A more promising source of minerals is to be found in the cobalt-rich manganese crusts, which are found as coats of the rocks of seamounts in the deep ocean. It appears that these are rich in cobalt at a depth of 1000 to 2000 m. The crust can build up to 10 cm or more on the often decaying volcanic rocks and can, in principle, be scraped off. There is some advantage in mining at them at a lesser depth, although this is offset by the more difficult technology for recovery. Some design work has been done in this field, especially by the United States and Japan. Many of the manganese-encrusted seamount are found within the exclusive economic zones (EEZs) and stimulated the interest of the US Geological Survey when their EEZ was surveyed by the long-range sonar.
