BEIJING(BullionStreet): China may begin deep sea mining to extract gold, copper and many other key minerals by 2030, according to the former head of the State Oceanic Administration.

Sun Zhihui said China has explored more than 80,000 square kilometers of the floor of the Pacific and Indian oceans so far and with the improvement in deep-sea technology, metal resources under the ocean can be explored and mined within 20 years.

He said commercial deep-sea mining by China and other country's can start as early as 2030 as they are developing technologies for commercial mining, but a low-cost method of mining polymetallic nodules has not been found yet.

The extent of the China's deep-sea exploration was catching up with that of advanced countries, he added.Scientists estimate that about 480 million to 13.5 billion tons of polymetallic nodules can be commercially mined.

Papua New Guinea's government granted the world's first commercial lease for deep sea mining in January to Canadian-based Nautilus Minerals, which will extract gold and copper from the sea floor 50 kilometres off PNG's north coast.

Last year, China was among the first group of countries approved by the International Seabed Authority to look for polymetallic sulphide deposits, a recently discovered mineral source, in the Southwest Indian Ridge, a tectonic plate boundary on the bed of the Indian Ocean, he said, adding the country is applying to explore for cobalt in a new area in the Pacific Ocean.

Polymetallic nodules are rock concretions, mostly about the size of a potato, on the seabed containing metals such as cobalt, manganese, iron, nickel and aluminum, which have huge economic potential.

Deep-sea environment was much more difficult to mine compared with land, because mining equipment has to endure high underwater pressures and marine corrosion.