source：Nikkei Asian Review
TOKYO -- Japan will deploy an autonomous underwater vehicle as early as next year as part of a government-backed search for industrially vital rare-earth elements, in what officials describe as the world's first survey of its kind.
The vehicle, developed by the U.S.-based Woods Hole Oceanographic Institution, will bounce ultrasound waves off the seabed 6,000 meters below the Pacific Ocean east of Japan.
Underwater surveys hold the potential to cover a wider area of the ocean floor than conventional sampling methods, which search point by point from surface ships. This limits their ability to determine the extent of rare-earth deposits.
The project comes at a time of growing international competition for rare earths, which are essential to the production of high-performance magnets used in electric vehicle motors, as well as LEDs and other technology.
China, the world's largest producer of these metals, has boosted output as the U.S. looks to exploit more of its own rare-earth resources.
Japan relies on China for about 60% of its rare-earth supply, but the waters around Minami-Torishima, an island over 1,800 km southeast of Tokyo, have been hailed as a potential domestic treasure trove of these minerals.
Plans call for sending the U.S.-made underwater drone into these waters, part of Japan's exclusive economic zone. The survey seeks to determine whether high concentrations of rare earths are present in seabed mud, and assess the size of any deposits.
If successful, the effort would mark the first use of an AUV for rare-earth exploration, officials say. Japan would then consider scaling up the survey to 10 vehicles. About 1 billion yen ($9.2 million) will be spent to acquire an AUV and related equipment.
Plans also include placing equipment on the ocean floor to enable the AUV to charge its batteries and relay data.
The Japan Agency for Marine-Earth Science and Technology, which will take part in the effort, has been developing a method of vacuuming up rare earths-laden mud from the seabed through a nearly 1,500-ton pipe lowered from a survey ship.
Sometimes called the vitamins of industry, rare earths comprise 17 elements including neodymium. The are added in small amounts to alloys and other materials to improve magnetism and other properties.
Japan has been working for years to develop domestic sources of these elements -- an effort that gained urgency in 2010 when China temporarily restricted exports of rare earths amid a diplomatic dispute with Tokyo.