A large-scale nodule collection test at ocean was conducted in 1997 at the end of a Japanese national R&D project of manganese nodule mining system. The collector passes were observed by a ROV, a side scan sonar, and a towed seafloor observation camera system for the post-test evaluation. Preliminary analyses of the results are introduced in the paper. Exact locations of the passes were recognized from the side scan sonar data. Many qualitative data such as soft landings, stick-and-slip movement, and smooth take-off of the collector were obtained from the ROV observation. Very important quantitative data such as settlement of collector sledge, volume of recovered nodules and sediments, and extent of resedimentation were measured from seafloor photos taken by the camera system.
Deep-sea manganese nodules, which have been found in considerable qualities and quantities at the Clarion-Clipperton Area in the Pacific Ocean, are expected to be one of potential mineral resources· of nickel, cobalt, and copper for the next generation. A Japanese national R&D project of manganese nodule mining system was started in 1981 and finished in 1997. The first 5-year phase was used to create fundamental technologies such as component and verification tests of the subsystems, and numerical modeling of the material flows and dynamic behaviors of the system (Wakabayashi et aI., 1986). Construction of the pilot mining system was started from 1986, but the progress was at a snail" s pace because of the budget shortage (Inokwna, 1995). In 1995, the plan for the pilot mining test was reviewed and four experiments to verify selected essential technologies that would contribute to the overall ocean development in the future were set in the final year. The four was nodule collection test, lift-pipe handling test, flexible hose bending test, and air-lift compressor operation test (Yamada and Yamazaki, 1998).
