Will humans mine for gold on the sea floor?

By Michael Kanellos
Staff Writer, CNET News.com

Published: December 6, 2005, 5:53 AM PST

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SAN FRANCISCO--The next gold rush might take place at the bottom of the sea.

Commercial mining companies are studying the possibility of extracting silver, gold, copper and other valuable metals from the volcanic vents found in the world's ocean floors.

"What is driving it is the increase in metal prices," said Peter Rona, professor of Marine Geology at Rutgers University, speaking at the 2005 American Geophysical Union, an annual conference on earth sciences taking place this week in San Francisco. "It is not out of the realm of possibility" that undersea mining could begin in a few years.

The most likely place where undersea mining might start is off the coast of Papua New Guinea, where a company called Nautilus Minerals has been exploring a series of offshore vents about 1.2 miles down since 1997. Volcanic vents in the seas near Tonga have also drawn interest from speculators.

The volcanic fields in the world's oceans form on the borders of tectonic plates: Metals from deep within the Earth well up through the cracks. The individual vents themselves are around the height of a human being and form in fields. In the Pacific, the fields are relatively small but are situated close to one other.

Volcanic fields in the Atlantic, which scientists two decades ago didn't believe existed, sit farther apart, but grow larger. The Trans-Atlantic Geotraverse (TAG) field, smack in the middle of the Atlantic, is about the same size as the Roman Coliseum.

"The TAG field is made up of iron, copper zinc and significant but smaller amounts of gold and silver," Rona said, although the location means it won't likely be harvested.

Volcanic vents have somewhat recently been discovered in the Arctic and Indian oceans. These fields remain elusive, asserted Robert Reves-Sohn, a scientist in the geology and geophysics department of the Woods Hole Oceanographic Institution. Scientists place a sensor in a can and then drag it around the ocean looking evidence of seismic activity.

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"This is a real needle-in-a-haystack problem," Reves-Sohn said.

Similar volcanic fields on the dry parts of the world were scoured long ago. "The fields on Cyprus were almost single-handedly responsible for the Bronze Age," Reves-Sohn said.

Huge environmental and commercial risks abound. Regional governments will need to create laws to supervise this activity, should it occur, said Rona. National governments have jurisdiction over their own coastal zones.

Some companies already exploit undersea volcanic vents for profit. Microbes that have evolved to feed off the chemical energy exuded by the vents are now harvested to produce enzymes. These enzymes then get used in food preservatives and in DNA fingerprint systems, Rona said.