Advance In Deep-Ocean Mining Systems Research

Advancement in deep-ocean mining technology is a great challenge not only for the resource exploitation, but also for scientific exploration. Future petroleum exploitation will benefit from this advancement. This paper reviews research, development and design aspects· of recent technologies for deep-ocean mining systems to recover manganese nodules and cobalt-rich manganese crusts from the seafloor at 800 - 6,000m depth. First, the seafloor crust is characterized on the basis of preliminary data from the recent survey in the Pacific Ocean. In the last 10 years, few significantly new technologies appear to have evolved in the nodule mining system. However, subsystems have been designed and tested systematically in Japan. Progress has been made in the seafloor miners (or collectors), hoisting systems, and pipe deployment and retrieval dynamics, materials, the system integration, and integrated system control. There was no at-sea test of any deep-ocean mining system since the 1970's. For the crust mining, the seafloor survey has been conducted in Some locations of the Pacific Ocean, and the physical characteristics and properties of only a fraction of the crust samples are tested, and more extensive survey is required at various locations of the Pacific to determine its distribution, abundance, and physical characteristics. The United States has a greater geological emphasis, while Japan has a greater engineering emphasis. Also, two crust mining system concepts are discussed. The deep-ocean submersibles will play a role in the ocean mining. Only Japan and India are currently active in the ocean mining program. Japan's national program has been preparing her first at-sea nodule mining testing in 1997. Until commercial mining operations of manganese nodules begin, the mining systems are expected to be continuously updated with the advancement of new support technologies. For the crust mining, the technical challenges are yet to be defined. This review updates that of Chung (1985).