Real Time Particle Size and Settling Velocity for In-Situ Monitoring of Deep-Sea Polymetallic Nodule Mining

In the coming decade, it is anticipated that deep-sea mining activities will commence throughout the deep ocean, at depths around 4000-6000m. At these depths, vast resources of minerals such as cobalt, copper and nickel, which are needed to produce batteries for electric vehicles for example, are present in the form of baseball-sized rocks called polymetallic nodules lying on the seabed. Collector machines driving on the seabed and gathering these nodules will stir up clouds of sediment, and there is concern about how the resulting concentration of sediment in the near-bottom ocean water will affect deep-ocean biology. As trials of collector vehicles commence, due to the great pressures at such depths and the remoteness of the locations, there is currently no technology capable of comprehensively monitoring the concentrations and properties of stirred up sediment in the deep ocean. This proposed effort will address the critical technology gap by developing a deep-sea monitoring system that uses novel laser-light scattering technology and high-resolution video imagery, with accompanying image processing, to measure the concentration, size distribution and settling speed of sediment. Very important is that these measurements will be made in-situ, meaning in their original place, since the sediment properties are so fragile that simply bringing up samples from the deep ocean and studying them is not an option. The technology can be mounted on all manner of deep ocean vehicles produce data in real time, which is vital for determining if deep-sea mining can be done in an environmentally responsible manner.