Treasure in the mud.

Nature uncovers a wealth of rare earth lying beneath the ocean floor:

The rare-earth elements — metals such as lanthanum and neodymium — are used to make strong magnets, which help to drive the motors in everything from laptops to electric cars and washing machines. Demand for rare earths has leapt from 30,000 tonnes in the 1980s to about 120,000 tonnes in 2010 — higher than the world’s current annual production of about 112,000 tonnes.

[Yasuhiro Kato, a geosystem engineer at the University of Tokyo,] and his colleagues… looked at 2,000 samples of sediments taken from 78 sites around the Pacific, and found rare-earth concentrations as high as 0.2% of the mud in the eastern South Pacific, and 0.1% near Hawaii. That might not sound like much, but those concentrations are as high as or higher than those at one clay mine currently in operation in China, they point out. And the deposits are particularly rich in heavy rare-earth elements — the rarer and more expensive metals.

Some of the deposits are more than 70 metres thick. The authors estimate that an area of 1 square kilometre around a hotspot near Hawaii could hold 25,000 tonnes of rare earths.

The problem will be getting the treasure out of the mud… without destroying all the weird ecosystems around the vents that put it there.