Autonomous Underwater Vehicle “BOSS-A” for Acoustic and Visual Survey of Manganese Crusts

[abstFig src='/00280001/10.jpg' width=""300"" text='Autonomous underwater vehicle BOSS-A' ]In order to effectively investigate the distribution and amount of cobalt-rich manganese crust (CRC), an autonomous underwater vehicle BOSS-A equipped with visual and acoustic instruments were developed. BOSS-A observes the seafloor along preset waypoints at a constant speed and altitude. Detailed 3D seafloor images can be obtained from the visual instrument, which employs a sheet laser and a camera. In addition, an acoustic instrument measures the CRC thickness beneath BOSS-A. The CRC at Katayama seamount was surveyed in February. The results visually presented the state and distribution of the CRC in this site and clarified the amount of the CRC. In the future, the authors will develop a more reliable thickness measurement method.

Preliminary Economic Feasibility Analysis of Cobalt-Rich Manganese Crust Mining for Rare Metal Recovery

The importance of cobalt-rich manganese crusts on the Pacific seamounts for possible future rare metal sources has currently been recognized. The thin layer-type deposit characteristics affect not only the excavation efficiency but also the economy of mining venture. Considering the thin layer-type distribution and the utilization of some rare metals in cobalt-rich manganese crusts, a preliminary economic feasibility of the mining venture is evaluated. Under some preliminary technical assumptions, the possibility of cobalt-rich manganese crusts for future rare metal sources for Japan is examined. The important role of utilization of rare metals in the crusts is highlighted.