Key points
- TMC’s 2022 test mining campaign found up to 98% of sediment entrained during nodule collection returns directly to the seafloor, with more than 95% settling within 1-2 kilometers of the collector vehicle.
- The midwater plume, released at 2,000 meters depth, dilutes to background concentrations within several kilometers of the outlet.
- Modeled at commercial scale for TMC’s Project Zero, the plume forms a pancake shape about 20 square kilometers in area and roughly 150 meters deep.
- TMC says the vertical separation between its 2,000-meter discharge depth and the shallower waters where fish forage and breed makes the risk to commercial fisheries negligible.
