The largest manufactures are former Nikopol Tube Plant, which is not divided into smaller plants, and Nikopol Ferroalloy Plant, which is the largest in Europe and second in the world in producing Ferromanganese ( FeMn ) and Ferrosilicomanganese ( FeSiMn ).
22.
In recent years, however, interest in deep-sea mining, especially with regard to ferromanganese crusts and polymetallic sulphides, has picked up among several firms now operating in waters within the national zones of Papua New Guinea, Fiji and Tonga.
23.
The Council of the Authority began work, in August 2002, on another set of regulations, covering polymetallic sulfides and cobalt-rich ferromanganese crusts, which are rich sources of such minerals as copper, iron, zinc, silver and gold, as well as cobalt.