China will build a multi-million dollar research base on its east coast to accelerate the study and exploration of deep-sea energy resources, officials with?the preparatory group of the base said Thursday.

The base covers 26 hectars of the ground and 62.72 hectares of the sea in the coastal city of Qingdao, Shandong Province, and will serve as a ground support station for China's manned submersible vehicle "Jiaolong".

Engineers have started to design the research base whose initial construction cost is estimated to reach 495 million yuan (around 72.8 million U.S. dollars), said officials from Ministry of Science and Technology and State Oceanic Administration.

Scientists believe sea beds at a depth of 4,000 to 6,000 meters hold abundant deposits of rare metals and methane hydrate, a solidified form of natural gas bound into ice that can serve as a new energy source.

The submersible, designed to dive to a depth of 7,000 meters, managed to reach 3,759 meters beneath the sea level at test runs conducted in this May and June. Its name "Jiaolong" is a mythical sea dragon in Chinese.

China is the fifth country in the world to have conducted a manned dive to more than 3,500 meters below the sea level, after the United States, France, Russia and Japan.

China's ambitious ocean exploration program began in 2002 and has involved more than 100 research institutes and companies, officials said.

The development of the submersible and its support vessel, as well as the selection and training of the crew took six years, oceanic administration officials previously said.

The submersible "Jiaolong" would be used for deep-sea natural resources inspections, as well as research and tests of equipment designed for deep-sea use.