Novel Rod-of-Scoops Control to Lower Sediment Disturbance in Deep Sea Mining

Abstract

Increasing demand for critical metals has renewed interest in deep-sea polymetallic nodules, but current hydraulic collectors risk ecological impact through direct benthic damage and sediment plumes. To bridge the gap between high-throughput but disruptive collectors and low-impact but slow AUVs, Rod-of-Scoops (RoS) is proposed: a synchronised dual-winch control mechanism to steer 2-DoF suspended scooping rods along trajectories designed to minimise sediment disturbance. This study aims to use 2D trajectory simulations, demonstrate precise time-accurate synchronised dual-winch control, and establish design envelope for potential commercial RoS model using a simplified scaling analysis benchmarked against the ~75 kg•s−1 ore throughput typical of industrial collectors. The study was conducted in three phases: (1) mining throughput under ideal conditions was estimated with 2D visualisations, and 2D kinematic model was used to simulate rod suspension dynamics; (2) bench control was designed to test and demonstrate time-accurate rod control; and (3) proof-of-concept of RoS was consolidated using an aquarium in lab setting. A synchronised DC-motor drive with 1 kHz bang-bang quadrature encoder feedback maintained less than 0.1 cm mid-path error and 0.2 cm endpoint error in bench testing, while aquarium trials in MESH 30–100 sand produced qualitatively background-level plumes that settled within 24 hours. Automated count-based pickup yield was 0–1%; post-hoc analysis suggests off-plane sway and scoop incidence angle rather than X-Y tracking precision as the primary yield limiters. These results quantify controller performance, highlight the qualitative nature of the current plume assessment, and reveal key mechanical upgrades required to pursue lower-plume selective harvesting at scale, positioning RoS as a conceptual pathway toward lower-impact deep sea mining pending quantitative plume and yield validation.

The Revolutionary Insight

Deep sea mining technologies is currently choosing between the economic caterpillar track vehicles or the unrealistic AUV nodule pickers. This paper introduces the “rod of scoops” concept which combines the best of both worlds.