Autumn 2006 / Leading Edge
Deep Sea Excitement

There is still no machinery for sea floor mining, but the technology exists

“Deep Sea Excitement” was the cover story of the Winter 1984 issue of this magazine, and in it geology professor Steve Scott made a bold prediction. In the future, he said, we would mine ore deposits from the ocean floor.

More than two decades later, that future is closer than ever. The world’s first successful commercial exploration for marine minerals took place this year on a deposit site Scott co-discovered in the western Pacific Ocean.

“I’ve been writing and talking about this possibility for a long time,” says Scott, the Norman B. Keevil Professor Emeritus of Ore Genesis at U of T. “Now I may actually see it happen in my lifetime.” The exploration results from the site – located 1,600 metres underwater off the coast of Papua New Guinea – exceeded his expectations. The drill cores and 15-tonne mineral sample obtained by Vancouver-based Nautilus Minerals Inc. contained very high grades of both gold and copper as well as some zinc, lead and silver. The company is now undertaking further exploration in the area.

The “deep sea excitement” described in the 1984 article sprang from Scott’s role in finding underwater hot springs fed by ocean floor volcanoes off the coast of British Columbia. Scientists had first identified these ocean vents, along with the rich mineral deposits they create, just five years earlier. The deposits are formed when water seeps into cracks in the sea floor, gets heated by a volcano and then sprays up through the vents, carrying within it dissolved minerals. When this hot water meets the cold water on the sea bottom, the minerals solidify and create chimney-like towers called “black smokers” which eventually collapse and become mineral deposits.

Scott was the first ore deposit geologist to see a black smoker during a research trip to the Gulf of California in 1982. He went on to co-discover several more with Australian colleague Ray Binns, including, in 1991, the Nautilus site under exploration. All along, he recognized both the scientific and potential economic value of the black smokers. As a scientist, he was interested in how sea floor mineral deposits could shed light on the formation of similar deposits that are being mined on land. Yet he also saw that, with the appropriate advances in deep sea technology, the black smokers could be mined for base and precious metals.

There is still no machinery for sea floor mining operations, but Scott says the technology exists to develop deep sea robotic devices that will extract minerals from depths of up to two kilometres. So far, the potential obstacles to launching a global deep ocean mining industry are not technological, but environmental. Some conservationists have expressed serious concerns about opening up the oceans to mining companies.

However, with oceans covering 70 per cent of the world’s surface and only a fraction of them having been explored for this type of deposit, Scott says sea floor mining represents a potentially huge new source of minerals to meet growing global demand – and causes less environmental damage than terrestrial mining. “This is an example of how pure, curiosity-driven research can eventually lead to a significant commercial venture.”

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