English Manganese nodule Cited by user Klbrain on 18 Nov 2023 Polymetallic nodules, also called manganese nodules, are mineral concretions on the sea bottom formed of concentric layers of iron and manganese hydroxides around a core.
English Deep sea mining Cited by user Joq Oliver on 08 Apr 2021 Deep sea mining is the extraction of minerals from the ocean floor found at depths of 200 m to 6500 m.