Exploration of the ocean bottom in the last fifty years revealed manganese nodules and phosphate nodules in many locations. More recently, polymetallic sulfide deposits have been discovered and polymetallic sulfide "black muds" are being presently deposited from "black smokers" [22] The cobalt scarcity situation of 1978 has a new option now: recover it from manganese nodules. A Korean firm plans to start developing a manganese nodule recovery operation in 2010; the manganese nodules recovered would average 27% to 30% manganese, 1.25% to 1.5% nickel, 1% to 1.4% copper, and 0.2% to 0.25% cobalt (commercial grade) [23] Nautilus Minerals Ltd. is planning to recover commercial grade material averaging 29.9% zinc, 2.3% lead, and 0.5% copper from massive ocean-bottom polymetallic sulfide deposits using an underwater vacuum cleaner-like device that combines some current technologies in a new way.