Modelling Deep-Sea-Mining-Generated Turbidity Currents.
Supervisors: Andrew Dale, Dmitry Aleynik, Esther Sumner (SAMS, Scotland)
This study presents the application of high-resolution hydrostatic models within the open-source Delft3D-Flow program to simulate turbidity currents generated by a collector vehicle for deep-sea mining at the Clarion Clipperton Zone of Belgian Global Sea Mineral Resources. The simulation outcomes reveal a limited ability of the models to replicate the field experiment, as they successfully reproduce the initial turbidity current head front’s arrival but fail to capture the subsequent ‘central patch’ and pulsating sediment load signals. This deficiency is attributed to factors like the presence of Kelvin-Helmholtz billows within the turbidity currents, the utilization of a hydrostatic model, and the omission of complexities such as turbulent and non-uniform background fluid, collector-induced wake turbulence, and intermittent sediment plume discharge. Nonetheless, the simulations effectively replicate the evolution of turbidity currents under the influence of background flow, illustrating disparities in height and velocity between turbidity current heads and leading to thicker sediment deposition near the collector track. Further investigations include scenarios incorporating variations in particle size distribution and seafloor topography. These scenarios demonstrate that sediment with larger grains leads to thicker yet localized deposition, while smaller sediment portions result in wider but thinner prevailing turbidity currents due to their extended suspension times. Additionally, a flat seafloor scenario prompts larger deposition areas compared to the original bathymetry of the Global Sea Mineral Resources. Coupling investigations into sediment plume dispersion with assessments of deep-sea organism responses is emphasized to formulate comprehensive regulations governing deep-sea mining activities.