Cobalt-rich ferromanganese crusts occur at shallower depths of <400 to about >5,000 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 of the countries.

Similar in general composition to the polymetallic nodules, cobalt-rich crusts are attracting investment in exploration for higher cobalt percentage (up to 2%), platinum (0.0001%) and rare earth elements besides nickel and manganese.

Cobalt-rich ferromanganese crusts contractors