There are three types of commercial value located between 400m and 6.5km depth:
- Polymetallic nodules are small grey balls containing nickel, manganese, copper and cobalt found between 3 and 6.5 km from the abyssal plains[i];
- Polymetallic sulfides are generally found at depths of 1 to 4 km in the vicinity of hydrothermal springs and hot springs on oceanic ridges[ii];
- Ferro-manganese crusts are metallic layers composed of iron and manganese oxides incorporating elements such as cobalt, platinum, titanium, vanadium and zirconium. They are located at depths of between 400 and 4000m[iii].
[i] United Nations Environment Programme. (2024), Issues note, Deep-Sea Mining. https://wedocs.unep.org/bitstream/handle/20.500.11822/45494/deep_sea_mining.pdf?sequence=3&isAllowed=y.
[ii] Idem.
[iii] Idem.