Manganese nodule resources in the northeastern equatorial Pacific

Recent publication of maps at a scale of 1:1,000,000 of the northeastern equatorial Pacific region showing publicly available information on the nickel-plus-copper content of manganese nodules has made it possible to delineate the limits of the prime area between the Clarion and Clipperton fracture zones which has been the focus of several recent scientific and commercial studies. The area, defined as that in which the nodules contain more than 1.8 percent nickel plus copper, is about 2.5 million square kilometers in size, and about half of it is assumed to contain nodules in concentrations greater than 5 kg/m² and averaging 11.9 kg/m². Assuming that 20 percent of the nodules in this area of 1.25 million square kilometers would be recoverable, its potentially recoverable resources are about 2.1 billion dry metric tons of nodules averaging about 25 percent Mn, 1.3 percent Ni, 1 percent Cu, 0.22 percent Co, and 0.05 percent Mo--enough to support about 27 mining operations each producing an average of 75 million metric tons of nodules over their lifetimes. Estimates based on other plausible assumptions would be higher or lower, but of the same order of magnitude. Thus it seems probable that the magnitude of the potentially recoverable nodule resources of the Clarion-Clipperton prime area--the most promising now known--is at most in the range of several tens of the average-size operations postulated.