Manganese nodules on deep ocean floor have received continuous attention as future resources for Co, Ni, Cu and Mn last five decades. The mining is a large-scale and long term venture. However, very few ecological assessments have been reported for it, due to the lack of a suitable assessment method. In this paper, the authors have applied an evaluation method named the Total Materials Requirement (TMR) for the ecological assessment of manganese nodule mining venture. Comparing the result with an economic evaluation, the authors propose an advanced method for a combined analysis of ecology and economy of deep-sea mining.
Manganese nodules on deep ocean floors have continuously received attention as potential sources for strategic metals such as Co, Ni, Cu, and Mn, due to their vast distribution and relatively higher metal concentrations (Mero, 1965; Cronan, 1980). Several registered Pioneer Investors have already identified promising sites in 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). The mining feasibility for manganese nodules, including an economic evaluation, has been examined in detail by some researchers (Andrews et al., 1983; Hillman and Gosling, 1985; Charles et al., 1990; Soreide et al., 2001). Owing to growing concern for the environmental impact of manganese nodule mining, multi-disciplinary environmental studies (oceanography, geology, geochemistry, ecology and geotechnical engineering) have been undertaken in many countries (Ozturgut et al. 1978; Ozturgut et al. 1980; Burns et al., 1980; Schriever et al., 1997; Trueblood et al., 1997; Radziejewska, 1997; Yamazaki and Kajitani, 1999; Sharma et al., 2003).