Deep-sea rock mechanics and mining technology: State of the art and perspectives

The review covers the development and the state of the art in deep-sea mining rock mechanics, equipment and challenges. It begins by introducing the significance of deep-sea mining, the types and geographical distribution of deep-sea resources. Section 2 reviews the mechanical properties and fracture mechanism of seabed and related continental rocks, which contributes to the advancement of relevant technologies and theories. Deep-sea mining systems developed by coastal countries are presented in Section 3. Seabed mineral collection systems are critically assessed in Section 4. Subsea mining vehicle is reviewed by walking mechanism and controlling system in Section 5. In Section 6, the development of subsea lifting system is detailed by dividing it into hydraulic and pneumatic lifting modes, and some technical problems in the lifting system are described. An in-depth description of surface support systems is presented in Section 7, which includes the deep-sea mining ship, dynamic positioning system, heave compensation system, launch and retrieval system, mineral disposing system as well as the storage and transferring systems. Section 8 discusses the challenges in the deep-sea mining, in terms of natural occurrence conditions, international legal framework and cooperative mining, environmental protection and economic benefits, etc. Finally, a brief summary and some aspects of prospective research are presented in Section 9.