Deep Sea Mineral Resources : Cobalt-rich ferromanganese

Cobalt-rich ferromanganese crusts occur at shallower depths of <400 to about > 5000 meters in areas of significant volcanic activity. The crusts grow on hard-rock substrates of volcanic origin by the precipitation of metals dissolved in seawater in areas of seamounts, ridges, plateaus and where prevailing currents prevent deposition of unconsolidated sediments and occupy large areas on top of these topography highs. In many cases, the deposits occur within the exclusive economic zone (EEZ) of the countries. Similar in general composition to the polymetallic nodules, cobalt crusts are attracting investment in exploration for higher cobalt percentage (up to 2%), platinum (0.0001%) and Rare Earth Elements (REE) besides Nickel and Manganese. The commercial interest in the cobalt crust is recent. The Authority has signed exploration contracts for cobalt-rich crusts with Japan, China and Russia. The experience of metallurgy of polymetallic nodules would help extracting metals from the cobalt crusts, however, the mining technology for these deposits is likely to be more complex than the polymetallic nodules.