Key points
- TMC’s collector weighs about 90 tons in air but only 15 tons on the seafloor with buoyancy applied, and post-pass surveys showed disturbance of just a few centimeters, versus roughly 80 cm of sediment churning from the older Archimedes screw design.
- The Coanda nozzle intake system, developed with Allseas, is designed to minimize sediment entrainment; onboard hopper separation keeps 95-98% of that sediment at the seabed rather than carrying it to the surface vessel.
- Data from TMC’s 2022 test mining campaign in the Clarion-Clipperton Zone found up to 98% of entrained sediment returns to the seafloor and more than 95% settles within 1-2 kilometers of the collector.
- TMC plans to release midwater discharge at 2,000 meters depth, below the upper-ocean biomass layer, and is evaluating sweep mining (500-1,000 meter passes) as an alternative to straight-line mining across 80-100 km transects.
