Well, there is plenty of metals simply laying on the ocean floor any way, but we cant get to that yet either, till recently.
Under the
UN's Convention on the Law of the Sea, mining rights on the ocean floor are controlled by a little-known body, the
International Seabed Authority, which since 2001 has issued 13 licences - with another six in prospect.
These licences, valid for 15 years, have been bought for $500,000 each by government organisations, state-owned corporations and private companies from countries including China, India, Russia, Japan and South Korea.
The high prices fetched for copper, gold and rare-earth minerals are leading to a surge in interest in mining the ocean floor. The idea first surfaced in the 1970s but was dropped because the costs were too high and the technology could not cope.
The nodules are known to contain up to 28% metal - 10 times the proportion found on land....
A similarly high metal content is found in another target for seabed mining: hydrothermal vents, chimneys formed by extremely hot water, rich in minerals. We reported on the
discovery of the world's deepest vents last month.
Stephen Ball, chief executive officer of Lockheed Martin UK, owner of UK Seabed Resources, says the engineering experience of offshore oil and gas operations and the trend to rising mineral prices have now combined to make seabed mining feasible.
"It's another source of minerals - there's a shortage and there's difficulty getting access, so there's strategic value for the UK government in getting an opportunity to get these minerals," he told the BBC.
China's domination of the global production of rare-earth minerals in particular has fuelled the search for other sources of materials essential for everything from electronics to wind turbines.
But many marine scientists and conservationists have warned that the implications of this deep-sea gold rush are not yet understood - and that mining nodules or hydrothermal vents could prove catastrophic for seabed ecology.