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ABSTRACT
Deep-sea polymetallic nodules have been traditionally considered as a potential resource for Ni, Cu, Mn and Co, however the recent research showed that they contain a large variety of metals, including molybdenum, zinc, zirconium, lithium, platinum, titanium, germanium, yttrium, and REEs, which increased their combined value as an alternative supplies for expanding economies and emerging green energy technologies.
The highest nodule abundance (more than 10 kg/m^sup 2^) with the high average percentage of metals (at least 2.5 % combined content for Ni+Cu, 0.2% Co, 30% Mn, 0.15% Zn, 0.07% Mo, etc.) were found at seafloor in the eastern equatorial Pacific (ClarionClipperton Fracture Zone, CCZ) and in the central equatorial Indian Ocean.
Within the recent decade, the International Seabed Authority (ISA) granted to ten national and multinational entities (Japan, China, Korea, India, Russian Federation, France, Germany, Tonga, Nauru, and Interoceanmetal Joint Organization) exclusive 15-years contracts for polymetallic nodules exploration in ten claim areas, each covering 75000 km^sup 2^ in the international seabed area. The commercial viability of nodule mining has yet to be established, but the size of deposits, the grade of several metals contained in nodules as well as the promising trends in metal market continue to motivate contractors to carry out their exploration activity.
This paper discusses the renewed importance of polymetallic nodule in the context of forecasted increasing demands for metals coupled with their environmentally advantages as alternative sources to land-based mining.
Keywords: polymetallic nodules, exploration activity, Clarion-Clipperton Zone.
INTRODUCTION
The deep seabed is one of the most potentially rewarding frontiers that challenge mankind in its exploration activity for marine minerals to ensure sustainable development and material achievement.
Polymetallic nodules as the primary mineral resource found in the deep seabed area promise to make an enormous contribution to the world's resource base. In particular, resources of polymetallic nodules in the eastern equatorial Pacific (within the Clarion-Clipperton Zone, CCZ) have 1.1 times more Mn, 1.4 times more Te, 1.85 times more Ni, 3.2 times more Co, and 4 times more Y than the entire global land-based reserves for those metals. Thus, metals in CCZ nodules as a percent of the total global land-based reserves are Cu 22%, Mo 63%, W 21%, Li 19%, Nb 13%, and REEs 11% [1,2, 3]. As a...