Manganese nodules are concretions with diameters averaging 4 cm (2 in) that occur in red clay
and ooze on the floor of the Pacific Ocean, with the major concentrations
around the Samoan Islands. They contain high concentrations of manganese.
They are thought to have formed as agglomerates from colloidal solution
(colloid) in the ocean's waters. The commercial
mining of the nodules is being delayed by legal controversy over international
rights to this valuable mineral resource. Although commercial lies in the
future, but work is centered on two systems – hydraulic suction dredges
and mechanical dredges.
|These are various ways of exploring for abyssal ore
nodules, include seismic surveying with an airgun (1) and a string
of hydrophones (2), echosounders (3), grab samplers with cameras attached
to them (4), oceanographic probes like the bathysonde (5), dredges
(6), deep-sea cameras (7), and wire-bound samplers, such as the box
AND PLANETARY SCIENCE