Massive Deposits of Rare Earth Elements Discovered under Pacific

July 5, 2011

A Japanese marine research team has just announced the discovery of deposits of rare earth beneath the Pacific that dwarf current reserve estimates.

Many of the high-tech products we use every day, including cell phones and PCs, depend on rare earth elements – a class of substances consisting of the 15 elements in the lanthanide group of the periodic table, plus the elements Scandium and Yttrium (which are included due their chemical similarities to the other lanthanide elements). These elements are used in the production of high-strength magnets, lasers, high-refraction lenses, petroleum separation catalysts, batteries and a wealth of other applications, in addition to having a number of medical uses. This makes them essential to our modern-day lifestyles, and 21st-century civilization as we know it would grind to a halt without them. And up to now, 97% of the world’s production has been controlled by just one country: China.

Despite their name, rare-earth elements are actually fairly plentiful. The problem is that they are highly dispersed throughout the earth’s crust, making recovery uneconomical except in a few locations. Inner Mongolia is one of the largest concentrated deposits, with an estimated 40 million tons sitting under the ground (other known, but much smaller, sites include South Africa, India, northern Europe and North America). Although global reserves are (were) estimated at approximately 110 million tons, China is the only major producer right now. Responding to fears that rising worldwide demand may deplete their natural reserves (and possibly also responding to the fact that they have near-complete control over a resource vital to the world’s  economy), China has tightened mineral exports, leading to a sharp increase in commodity prices and correspondingly higher production costs for many high-tech goods. In one notable incident, following a collision in 2010 between a Chinese fishing vessel and a Japanese Coast Guard vessel, Japan immediately backed down from its side of the dispute after China threatened to cut off rare earth exports to them altogether, despite video evidence that the Coast Guard vessel had been deliberately rammed. Following this display of economic helplessness, rare earth prices tripled Japan, sparking new initiatives to recycle electronics so that the materials can be recovered.

So Japan, and much of the rest of the world, has been over a barrel with regard to the rare earth element supply. This made today’s news of the discovery of massive high-concentration deposits under the Pacific Ocean very interesting. According to Associate Professor of Earth Science Yasuhiro Kato, of Tokyo University, “The deposits have a heavy concentration of rare earths. Just one square kilometer of deposits will be able to provide one-fifth of the current global annual consumption.” The discovery was made by a team from the Japan Agency for Marine-Earth Science and Technology, led by professor Kato, which had been taking study samples from over 2,000 sites around the Pacific. The results of their study, which were published Monday in the British journal Nature Geoscience, found the highest concentrations of rare earth elements over an area of 8.8 million square km near Hawaii and an area of 2.4 million square km around Tahiti, with total deposits estimated at 100 billion tons, exceeding previous estimates of the elements abundance by a factor of a thousand.


Map of the concentrations of rare earth elements found by Kato's team. The size of the circles indicates concetration (ppm) of the elements. The highest concentrations were found near Hawaii and Tahiti.

via Asahi Shimbun

Although the deposits are under 3,500-6,000 meters of water, they are very close to the surface of the sea bed, being found mainly in the top 8-20 meters of mud and sediment. Recovery will still be difficult and costly, and although many mining companies have already voiced interest in exploiting undersea mineral sources, Chinese producers are not in any danger of losing their near-monopoly anytime soon. Further complicating matters, undersea mining could have severe environmental consequences, and environmental groups are worried about the possible effects on marine ecosystems.

Should these difficulties be overcome, Japan would still not achieve the rare earth self-sufficiency they desire, although having the option of purchasing from the US or France would no doubt be preferable to depending only on China. Few deposits were found within Japan’s own Economic Exclusivity Zone, which extends approximately 370km from the coast, but Professor Kato has commented that “future studies will have to be done focusing on Japan’s EEZ.”


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