Introduction - The Abyss in Question

Deep-sea mining refers to the extraction of mineral resources from ocean floors at depths exceeding 4,000 meters. Three types of deposits are of particular interest: (1) polymetallic nodules, concretions rich in nickel, cobalt, copper, and manganese scattered across abyssal plains like the Clarion-Clipperton Zone in the Pacific; (2) polymetallic sulfides from active or extinct hydrothermal vents (laden with copper, zinc, gold, silver, etc.); and (3) cobalt-rich crusts covering certain seamounts. These abyssal deposits represent immense potential: the Clarion-Clipperton Zone alone is estimated to contain over 21 billion tons of nodules, sufficient to supply the battery and energy transition industries for decades.

Why such enthusiasm? On one hand, the rush for these underwater minerals is driven by the quest for critical metals essential for electric vehicles and renewable energies (nickel, cobalt, rare earths, etc.). Industrial players see a new frontier to secure strategic raw material supplies, given the depletion or geographic concentration of certain terrestrial deposits. Additionally, the allure of technological innovation — robotic vehicles, giant pumps, collector ships — evokes a Jules Verne-like imagination, supported by significant R&D investments over the past decade.