'Sea dragon' ventures 5,000m below sea to find jewels of the deep

China leads the way as discovery of rare-earth metals on floor of the Pacific Ocean triggers race to the bottom

China has boldly gone where few nations have gone before. It has sent a manned submersible vessel to a depth of 5,000 metres below the sea in its attempt to dominate the scientific exploration of the mineral-rich seabed. The Jiaolong, China's first manned deep-sea submersible craft, has reached a depth of 5,057 metres (16,591ft) in the second of four planned programmes of dives that may take it as deep as 7,000 metres next year – deeper than the 6,500-metre record for civilian research submersibles set by Japan in 1990.

The 8.2-metre long Jiaolong, which means "sea dragon", carries a crew of three and weighs nearly 22 tonnes. The vessel represents China's ambitious attempt to match the technological prowess of the four main deep-sea diving nations – the US, Russia, France and Japan.

This week's dive means that China is now theoretically capable of reaching 70 per cent of the ocean floor, but if the Jiaolong reaches its designed depth of 7,000 metres in 2012, it will be able to cover more than 99 per cent of the global seabed, experts said. Much of the deep sea floor is totally unexplored, but scientists believe there may be rich deposits of minerals and precious metals, especially around hydrothermal vents on the seabed where hot plumes cause the build-up of mineral-rich "chimneys", first photographed by the American submersible Alvin in 1979.

Japanese researchers recently announced the discovery of large deposits of rare-earth metals on the floor of the Pacific Ocean. Such elements are essential for the micro-electronics industry and China already accounts for more than 95 per cent of the world's production.

China started work on developing the Jiaolong in 2002. It took six years to complete the construction of both the vessel and its mother ship, involving about 100 institutions and companies from around the world. The Jiaolong's record dive received wide coverage by the state-controlled media in China where commentators there compared the feat to recent Chinese achievements in manned space flight.

"It will pave [the] way for a record-breaking 7,000-metre test dive in 2012," Wang Fei, deputy director of the State Oceanic Administration told the Xinhua news agency. "The purpose of this diving programme is to find problems with the Jiaolong and improve it constantly. At a depth of 5,000 metres, the Jiaolong withstood great pressure amounting to 5,000 tonnes per square metre," he said.

The Jiaolong is diving in international waters in the north Pacific Ocean between Hawaii and North America.