Key points
- Allseas’ diffuser system releases excess water used in nodule collection back into the environment, returning up to 95% of entrained sediment at the diffuser level before it can enter the riser system.
- The diffuser slows and concentrates the exiting flow, promoting formation of a gravity current that hugs the seafloor and stays within a couple of meters of the bottom.
- During TMC’s 2022 test mining campaign in the Clarion-Clipperton Zone, more than 95% of entrained sediment settled within 1-2 kilometers of the collector vehicle.
- Sediment discharged at 2,000 meters depth in the midwater column dilutes to background concentrations within several kilometers.
