Full-scale experiments on a coandă-effect-based polymetallic-nodule collector

Polymetallic nodules are potato-sized rock accretions that form on vast areas of the abyssal plains of the global ocean. These nodules are rich in commercially precious metals, such as nickel, cobalt and copper, making them a target for potential future deep-sea exploitation. Generally, polymetallic nodules are partially buried in the seabed sediment, which is predominantly composed of clay. Among the existing mechanisms for mining polymetallic nodules (mechanical, hydraulic and hybrid), hydraulic collecting is deemed the most suitable technology in deep sea mining. This is primarily because hydraulic collecting hardly involves interaction with the seabed during the collection process (Agarwal et al., 2012); the collector generates a pressure gradient to harvest the nodules, thus substantially reducing the associated disturbance to the seabed.