Deep-sea polymetallic nodule mining: a review of cost reduction and efficiency technologies

Existing reviews on deep-sea polymetallic nodule mining focus only on structural optimization of individual equipment, lacking a systematic analysis of full-chain key technologies oriented to the core dual goals of “cost reduction and efficiency enhancement”, which cannot support the commercialization process. To fill this gap, this paper systematically sorts out the technological progress and bottlenecks in three core stages (seabed mining vehicle mobility, mineral collection, and ore lifting) based on the full-chain technical framework of “precise seabed nodule collection – long-distance stable transport”, and explores feasible cost-saving and efficiency-enhancing solutions. The results show that the unique soft sediment properties in nodule-rich areas (water content 312%–577%, internal friction angle < 8°, undrained shear strength 4.0–15.5 kPa) are the primary factors limiting equipment stability. Optimized sharp triangular track shoes increase maximum traction by 120% under typical working conditions (15% slip ratio, 0.6 m/s travel speed), while thick triangular ones achieve 70.4% higher traction with 18% weight reduction. Hydraulic collection dominates current technologies, with the Coandă effect scheme reaching 87% maximum efficiency, and multi-stage centrifugal hydraulic lifting is the engineering focus. Innovatively, the synergy of mining and carbon sequestration increases unit revenue by 606.3% and reduces CO 2 sequestration cost by 62.8%, while the ORC system for wastewater energy recovery covers 15–20% of total mining electricity demand. Core commercialization obstacles include uncoordinated mobility-collection systems, unstable pipeline transport, poor material adaptability to extreme conditions, and high costs. This paper clarifies key breakthrough directions for full-chain optimization, providing a systematic framework and technical reference for the industrialization of deep-sea polymetallic nodule mining technologies.