Large hydrothermal metal deposits found off Kume Island

Researchers at JOGMEC, Japan Oil, Gas and Metals National Corporation, have identified large sea-floor hydrothermal deposits on the seabed off Kume Island.  JOGMEG officials describe it as one of the largest hydrothermal deposits in Japanese coastal waters found to date.

JOGMEC is planning to start an excavation survey of the site with the aim at eventually starting commercial mining. The deposit contains large amounts of copper, and it might be possible to mine minerals worth three to four times the commercial value of existing similar large-scale deposits.

The deposits are about 30 km west of Kume Island about 1,400 meters below the surface of the sea.  They are located within a 300-meter area, and the researchers say there are more than 100 points where minerals are concentrated.

In addition to copper, the deposits contain a significant amounts of lead, zinc, gold and silver.  Gallium, one of rare metals used mainly in electronics, is also present in small quantities. Last December, a number of large thermal vent chimneys were discovered near the site.