Handling of Bulk Solids in a Marine Environment from Seabed to Shore

Abstract

In this chapter, the work that is being done in relation to machine-cargo interactions relevant to deep-sea mining is elaborated. To ensure safe and efficient operations across the entire mining value chain, it is important to be aware of the implications of certain design and process decisions. An overview of mechanisms influencing the mechanical response of the bulk materials and the main effects leading to (mechanical) degradation of the ore, e.g., fragmentation, abrasion, is presented. Although the concepts are applicable to each of the deep-sea deposits, our focus is on polymetallic nodules in a riser-based concept. Results are discussed of experiments in which nodules are fragmented due to particle-particle collisions and collisions with different handling equipment, such as the seabed harvester, riser pipe, pump impeller, pipe bends, etc. Next to fragmentation, degradation due to abrasion occurs due to particles rolling, sliding, and colliding with each other, resulting in the generation of nodule fines. Based on the same set of nodules, mechanical bulk properties of dry and wet nodules are studied. The obtained results provide relevant insights for the design of the nodules handling equipment. Furthermore, modelling approaches applied to other fragile bulk materials where the breakage and generation of fines play an important role are outlined. It is described how these modelling approaches can assist in the design of handling equipment, and recommendations are given for next steps to further optimize their design.