Survey technologies for deep-sea manganese nodule deposits were developed in 1960s and 1970s. Though some of them are still applicable, innovative technologies are required for newly found marine mineral deposits, such as hydrothermal metalliferous deposits from ocean ridge and are areas and cobalt-rich manganese deposits from seamounts, considering their different distribution characteristics. For examples of current survey technologies, acoustic equipment, seafloor observation systems, sampling tools used in the R/V Hakurei-maru No 2 are briefly introduced. Requirements are examined from viewpoint of the mining interests, and some breakthroughs for more advanced survey for the deep-sea mineral deposits are discussed.
Manganese nodules in deep ocean basins are still considered as the most promising deposits for commercial mining. Under the Law of Sea Treaty, possible pioneer investors are regulated only on the nodule development procedures. The detailed distribution characteristics in the Clarion-Clipperton Area were investigated in 1960's and 1970's. However, only a few have been published (von Stackelberg and Beiersdorf, 1991; Jeong et al., 1994), because the data are confidential to get mining claims for the ventures. Some interesting geotechnical data were obtained by a manned submersible (Cochonat et al 1992). Cobalt-rich manganese deposits in the equatorial Pacific Ocean seamounts are regarded as possible mineral resources for cobalt, nickel, and platinum in the next generation (Halbach, 1982; Cronan, 1984; Manheim, 1986). Geological distribution of the deposits has been studied by many previous researchers (Halbach et al., 1982; Hein et al., 1985a and b; Pichocki and Hoffert, 1987; Misawa et al, 1987, Cronan et al., 1991a and b). In the Mid-Pacific Mountains, the deposits have been surveyed by a Japanese research vessel (R/V), Hakurei-maru No 2 since 1987. Hydrothermal metalliferous deposits in the Pacific Ocean were firstly found in the Galapagos Lift in 1977 (Lonsdale, 1977).