Activities on Manganese Nodules During the Post-war Boom

Economic interest in manganese nodules commenced in the late 1950s. Early compilations of compositional data on them identified the NE tropical Pacific as being an area rich in nodules containing above average Ni and Cu, this area being later whittled down to the Clarion-Clipperton Zone, the sea floor between the Clarion and Clipperton Fracture Zones. Cobalt-rich nodules were found between the island groups of the South Pacific. In the Atlantic Ocean, nodules were found to be much less abundant than in the Pacific and to be of little economic interest. In the Indian Ocean, nodules of potential economic interest rich in Ni and Cu were found to occur in the Central Indian Ocean Basin south of the equator. These initial reconnaissance observations in the 1960s were followed in the 1970s and 1980s in the Pacific by nodule sampling transects from one depositional environment to another, partly as an aid to developing exploration methods for the deposits and partly to help understand their origin. What actually constituted a manganese nodule resource engendered much discussion in the 1970s and 1980s with several different interpretations. Likewise, how many mine sites might be available was contentious, as was the throughput needed to sustain one. Nevertheless, economic models of the late 1970s and 1980s suggested that nodule mining could be profitable under certain circumstances, given a large number of assumptions. In fact, though, no nodule mining ever took place in the twentieth century.