Development of Potential Examination Method for Cobalt-Rich Manganese Crusts.

Abstract

ABSTRACT:Cobalt-rich manganese crusts on seamounts and manganese nodules on deep ocean floor have both received attention as future resources for Co, Ni, Cu, and Mn. Lack of information on cobalt-rich manganese crusts has precluded comparisons between the two sources in terms of their technical and economical advantages. In the past 15 years, Japan has surveyed the cobalt-rich manganese crusts; therefore, it seems the proper time to compare the two. In this paper, we consider deposit features and R&D results to produce a method for this comparison. Technical and economical advantages and disadvantages for each are given from a preliminary examination, followed by a discussion of the additional information required for a thorough comparison using our methodology. INTRODUCTIONBoth cobalt-rich manganese crusts on seamounts and manganese nodules on deep ocean floors have received attention as potential sources for strategic metals such as Co, Ni, Cu, and Mn, due to their vast distribution and relatively higher metal concentration (Mero, 1965; Cronan, 1980). Because similar metals are contained in both, future needs may require that we select between the two. Several registered Pioneer Investors have already identified promising sites in the deep-sea regions for manganese nodule mining (ISA, 1998), and appropriate mining technologies have been developed during the last thirty years by the international consortium and several nations (Welling, 1981; Kaufman et al., 1985; Bath, 1989; Charles et al., 1990; Yang and Wang, 1997; Yamada and Yamazaki, 1998; Hong and Kim, 1999; Muthunayagam and Das, 1999). On the other hand, the only reported information on potential areas for the cobalt-rich manganese crusts has been scientific in nature (Cronan, 1984; Clark et al., 1984; Misawa et al., 1987; Pichocki and Hoffert, 1987); only one systematic feasibility study has been published (Hawaii DPED, 1987).