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Mining the ocean floor for mineral treasure

Posted in America, Engineering, Nature, Science, Sea, Ships on Thursday, 20 December 2012

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This edited article about marine science and exploration originally appeared in Look and Learn issue number 800 published on 14th May 1977.

Underwater scene, picture, image, illustration

Many mineral treasures are found on the ocean floor

One day last February, a freighter left the Oregon harbour of Portland and nosed quietly into the deep ravine of the Columbia River on the first lap of the greatest treasure hunt of all time.

The German officers, Spanish crewmen and American mining experts aboard the 545-ton Deep Sea Miner II were not dreaming of golden doubloons and jewels cascading from some ancient chest lodged in the sunken wreckage of a long-forgotten galleon. They were on the trail of the natural trove of the deep – King Neptune’s very own treasure that is worth untold millions to the men who can pluck it off the sea-bed beneath the oceans of the world.

There, miles beneath the waves in the wandering abysses of the sea-bed lie strange, briquette-like lumps known as nodules, impregnated with precious ores sought by every nation in the world. Set in these nodules, which range in size from potatoes to footballs, is manganese – the mineral that toughens steel – and copper, nickel, cobalt and 30 other metals.

The South Pacific alone is estimated to contain as much as 1.5 million tons of nodules, and so at roughly £150 a ton, the potential economic boom from developing this single region enters the realm of the unimaginable.

United States defence experts have even come up with some equally staggering figures that confirm the existence of a veritable Eldorado of the Deep. They reckon that the Pacific can provide enough copper for 1,100 years, enough nickel for 23,500 years, enough manganese for 34,800 years and enough cobalt for 260,000 years.

And, strangely enough, every year more and more nodules are being thrown up by mysterious convulsions and volcanic eruptions in the inky depths. Some 55,000 tons of copper are added annually to the Pacific Ocean floor.

Yet how can these nodules be gathered from such vast depths? Officials of Deepsea Ventures Incorporated, the combine behind the voyage of the Deep Sea Miner II, believe they have the answer.

These pioneer miners of the ocean floor, which lies up to three miles beneath the heaving decks of their converted ore carrier, have for many years been perfecting methods of bringing the prized nodules to the surface.

They tried slinging a cable with bucket-like scoops attached to it down to the sea-bed where the nodules were dredged up. They hoped to produce 3,000 tons over two years but, in fact, this laborious, hit-and-miss process only yielded seven tons.

Today, they favour a hydraulic system, which is like a gigantic vacuum cleaner. A pipeline connects the ship with a dredge-head that moves systematically over the sea-bed. Compressed air is forced into the pipeline at several points. As it rises inside the pipeline, the bubbles expand creating a lifting force that sucks the nodules up to the surface and the waiting ship.

So far the financial backers, the US Steel Corporation and Union MiniËre of Belgium, have pumped about £12 million into the scheme, which they estimate could cost more than £300 million if a full-scale plant for processing the minerals is built. Until that stage is reached, however, the minerals found in the nodules will be processed in Belgium.

Deep Sea Miner II is believed to be capable of handling between 750 to 1,000 tons of nodules daily from an area, for which its owners lodged the first-ever ocean mining claim in 1972.

The area, 1200 miles south-west of Los Angeles, covers about 35,000 square miles. Before setting out on their first real attempt to mine the precious nodules in quantity, the treasure-seekers tested their gear off the mouth of the Columbia River. Afterwards they set sail for Los Angeles where they took on 16,000 feet of piping. Then the big adventure began as Deep Sea Miner II ploughed through the Pacific waters for the chosen area. It will last for many months.

Manganese nodules are found mainly in areas where the water is rich in oxygen. The nodule beds most favoured for mining – those with the highest copper and nickel content – apparently lie in the Pacific south-west of Hawaii and just north of the equator where there is high biological productivity. The richest deposits occur in a narrow band, perhaps no more than 289 kilometres wide and 2,000 kilometres long, running roughly east-west around 190∞ at a depth of about three miles.

It was a British expedition ship, HMS Challenger, that first discovered nodules in 1873. But they were of no more than an academic interest for 75 years. Interest in them rose in the 1950s when University of California geologists found a large quantity of nodules containing cobalt near Tahiti.

High concentrations of nodules are also found along the southern edge of the equatorial belt, but these, like the ones in the Atlantic and Indian Oceans, are relatively poor in copper and nickel.

But the vital question of legal claims to the ocean floor has aroused worldwide controversy. Britain, for instance, has already opposed the right of Deep Sea Ventures to mine the Pacific sea-bed. Indeed, the fight over who should control the vast deposits of ores beneath the seas has occupied experts from 156 nations many years in the conference halls of the United Nations in New York.

In the skyscraper block, which acts as a forum for international debates and quarrels, the member nations of the Law of the Sea Conference will gather again this Spring to try to bring some semblance of order to the growing quest for the spoils of the oceans.

Already they have set up a body known as the International Sea-bed Authority with an operating arm called The Enterprise. The world’s poorer countries want this organisation to have the sole right to exploit the sea-beds in international waters – those areas far outside the fishery zones surrounding national coastlines.

For many of the world’s developing countries are veritable landlocked islands, sandwiched in the centres of continents, without any merchant fleet or navy or direct claim to maritime wealth. They do not accept that they should be unable to benefit from the sea-bed riches.

On the other hand, the United States, which is confident of leading the field in the new technology, oppose controls and argue that as they are making a risky investment in a perilous field they are entitled to eventual profits. But they are prepared to co-operate with other interested countries.

Another stumbling block has been provided by Russia, which would like to see only State-owned companies permitted to undertake the mining operations.

So reconciling the interests of the world’s most powerful nations with those of developing countries and working out a system of legal controls will present a daunting task for the 1,400 delegates when they meet in New York. For the UN regards the sea-bed minerals as “the common heritage of mankind” and as such to be shared by every nation, not just the lucky ones.

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