Experimental study of nodule detachment efficiency and environmental impact of a double-row jet collector

Hydraulic jetting is an effective method for collecting polymetallic nodules in deep-sea mining operations. The jetting process detaches nodules from the seabed sediment, leading to the suspension of sediment particles. Consequently, the collection process directly impacts the economic viability and environmental impact of deep-sea mining projects. This study examines the detachment performance of nodules and the factors influencing suspended sediment particle concentration using a double-jet collection model under various jetting parameters. A deep neural network model is developed to predict nodule detachment performance and suspended particle concentration, followed by a sensitivity analysis. The results indicate that the nodule detachment rate is positively correlated with jetting time and velocity but follows a parabolic relationship with the ratio of nozzle spacing to jetting distance (B/H). The ratio of nodule detachment rate to seabed erosion disturbance demonstrates the existence of a specific B/H range where optimal nodule detachment efficiency is obtained at smaller amounts of seabed disturbance. The suspended particle concentration initially increases, then stabilizes at a relatively constant level, the stabilized suspended particle concentration following a power-law relationship with sediment erosion volume. Neural network analysis reveals that jetting velocity and B/H are the most influential factors on nodule detachment rate, while B/H is the most significant factor affecting suspended particle concentration. •Monitoring of nodule detachment and suspended sediment concentration at varying jet parameters.•The study elucidated the inherent relationships among sediment erosion, nodule detachment and plume concentration.•A high-precision neural network was developed to predict nodule detachment rates and plume concentrations.•The study reveals key factors influencing nodule detachment rates and suspended sediment concentrations.