Copper, cobalt, rare earths: At the bottom of the deep sea lie treasures, which really only need to be salvaged. But the costs and consequences are unclear.

From Alexander's forehead

The gold is on the floor. You just have to find it. And mill out. And suck in. And bring them to the surface of the sea, cart them ashore, separate, clean, process. And then hopefully earn some more money with it.

Raw materials from the sea floor - be it gold, copper or rare metals such as lanthanum and cobalt - have cast a spell on mining companies. Deep in the ocean, up to 6500 meters below the surface of the sea, a brave new world of underwater mining is spreading: manganese nodules that lie like potatoes on the sea floor and only need to be picked up. Cobalt crusts that cover the slopes of submarine mountain ranges - rock-hard, but rich in metals. And sulphide layers that have deposited on the sea floor around hot springs and contain not only stinking sulfur, but gold and silver.

It is a huge treasure that basically just needs to be raised. And the chances are not so bad: "For a long time, for more than 100 years, mining in the deep sea was nothing more than an idea," says Mark Hannington, head of the department for marine raw materials at the Kiel marine research center Geomar. "But now the economic, political, technical and scientific challenges have reached a point where they seem feasible."

Knowledge of the deep sea has not kept up with human activity there

However, it remains to be seen whether they are also feasible - and whether mining is justifiable for ecological reasons. Because the deep sea is reluctant to reveal its treasures: more than half of the earth is covered by oceans kilometers deep. It's cold and dark in them, and the pressure is enormous. The deep waters are also a rich source of nutrients, they store carbon dioxide from the atmosphere, they are habitat for a multitude of very different species. Any intervention can be fatal.

Not much more is known about the oceans. "Unfortunately, our knowledge of the deep sea and its ecosystems has not kept up with the rapid increase in human activity in the water," says Lisa Levin, director of the Center for Marine Biodiversity at the Scripps Research Center in California. “And right now, when commercial and strategic interests overtake science, are we preparing to mine raw materials?” Levin, like many of her colleagues, is not enthusiastic. The researcher urges caution. “We need a balance between the need for these raw materials and the protection of ecosystems with their diverse functions.” But what could this balance look like? How can the unknown be protected?

Not digging at all does not seem to be an alternative - after all, at first glance there are good reasons for mining on the seabed. "Worldwide demand for raw materials and minerals has risen sharply recently, not least due to the economic upswing in countries like China and Brazil," says Hannington. The miners have to penetrate deeper and deeper into the earth's crust, mining is becoming more and more expensive, and it is becoming increasingly difficult to find minerals of high quality at all.

In addition, the raw materials are very unevenly distributed across the globe. According to calculations by the World Ocean Review, about 40 percent of the metal cobalt that is used in batteries and particularly resistant steels comes from the Democratic Republic of the Congo - an extremely poor, politically unstable country. The imbalance is even greater for the so-called rare earths. Here, 97 percent come from China, including the silvery metal lanthanum, which is mainly needed for batteries. The battery of a modern hybrid car can contain more than ten kilograms of this valuable substance. "So it is not surprising that the interest in getting these rare earths out of the deep sea in the future is growing," says Lisa Levin.

From a purely technical point of view, there seems to be little to counter this. “We have recently made great strides in deep-sea robots, we have access to the ocean floor like never before, we can get there and do tasks,” says marine biologist Cindy Lee Van Dover of Duke University in North Carolina, USA. The first companies want to take advantage of this: The Canadian company Nautilus Minerals has been working on its mining robots for a long time. Next year, the white machines should finally be used - in the Bismarck Sea east of Papua New Guinea. There, at a depth of 1600 meters, the company discovered an eleven hectare sulphide layer. With up to 15 grams of gold per recoverable ton, there is three times as much precious metal on the ocean floor as in typical deposits on land. In the case of copper, the concentration is twelve times as high.

In order to get to the treasures, a small robot should first level the ground. A second, large machine will then mill off the sulphide layers. A third caterpillar sucks them in and takes them to a huge underwater pump. From there, the mud is pushed to the surface through a 30-centimeter-thick pipe to a ship. It is drained, the wastewater is filtered and pumped again 1500 meters into the depth - to where it came from. The remaining rubble is reloaded and towed to a port 50 kilometers away, where it is to be processed.

Much of the technology comes from oil and gas production, which has been searching, drilling and welding at similar depths for decades. Mark Hannington is still skeptical. “Anyone who speaks to engineers, especially from the oil industry, will hear that mining is a purely technical and therefore solvable problem,” says the marine researcher. "However, we worked on the Geomar long enough at such depths to know that this is a particularly hostile place - for machines and for any other activity."

There are currently no machines to mine the manganese nodules and cobalt crusts. A few years ago, the German Federal Institute for Geosciences and Raw Materials at least ordered drafts for harvesting the tubers, which requires plowing the seabed to a depth of five centimeters. There are only concept studies for breaking down the crusts, which have to be separated from the mountains below with a chisel. According to estimates by the World Ocean Review, more than a million tons of cobalt crust with a thickness of at least four centimeters would have to be removed annually to make the effort worthwhile.

For Mark Hannington, this inevitably leads to the question of whether such mining can even make economic sense - especially since constantly rising raw material prices are not guaranteed, as the current oil shows. At the end of the 1970s, a gold rush hit the deep sea. At that time Germany also wanted to mine sulphide layers and manganese nodules. Then the prices of raw materials fell, and deep-sea mining with its immense effort was no longer worthwhile. The activities fell asleep.

Even today, the spirit of optimism is not clear. On the one hand, there are the numbers, and they sound promising: According to Van Dover, a typical sulphide field could contain 1,5 million tons of degradable material. With an average copper content of eight percent, mining the reddish metal alone would bring in nearly $ 700 million, not to mention the additional gold and silver. On the other hand, there are incalculable costs: The chunks not only have to be mined and brought to the surface, the engineers also have to process them, ship them ashore, extract the metal, clean it and sell it. And they have to be aware that they can face costs that they still have no idea of ​​today - be it due to technical difficulties or new environmental regulations. “Only when all of this is added up will it be clear whether there is really any real money to be made from deep-sea mining,” says Hannington. "Everyone in the industry is therefore eagerly waiting for someone to finally start."

However, nobody wants to miss out on the possible billions: The International Seabed Authority (ISA), which coordinates the exploitation of the deep sea from Jamaica, has now issued 19 licenses to explore maritime deposits. While Nautilus Minerals intends to prospect within the 200-mile zone of Papua New Guinea and therefore only has to negotiate mining rights with the island state (which has dragged on for years), most of the other deposits are in international waters. States - but also companies - can acquire a license to explore promising parcels from the ISA. Germany has already done this, as have France, India and China.

Sea cucumbers, worms and snails will not be able to escape fast enough

In the case of manganese nodules, these fields may be 150 square kilometers; 000 years are allotted for the exploration. The states are then allowed to start mining - but only on half of the area, the rest should be made available to poorer countries. In doing so, the ISA, which was brought into being by the United Nations Convention on the Law of the Sea, wants to fulfill its actual purpose: to manage raw materials in the sea as the legacy of humanity and as a common resource for all states.

The first exploration licenses will expire next year. The states then have to decide: Do they want to extend the exploration by five years, do they want to write off their license fees and give up the plot or do they actually want to mine it? However, the ISA has yet to determine under which legal and ecological framework conditions mining may then be operated. In view of the scarce knowledge about the deep sea habitat, marine biologists do not expect anything good - especially since the ISA is not an environmental protection organization. “The main purpose of the seabed authority is to get people into mining. After all, that's the ISA's source of income, ”says Van Dover.

Even if little is known about the ecosystems on the ocean floor, one thing seems clear: the mining of raw materials will not be without consequences. The machines that are supposed to harvest manganese nodules, for example, inevitably stir up sediments. Currents can capture these clouds, transport them away and deposit them in other regions. Sensitive organisms, especially those sitting on the ground, are covered up and die. Sea cucumbers, worms and snails that cannot escape the plow fast enough also have no chance. Many frightened animals are finally caught by the teat that is supposed to collect the tubers.

"If we lose the tubers, we also lose the species that only live there," says Van Dover. They come back very slowly, if at all: In a large-scale experiment, German ocean researchers plowed up an area of ​​several square kilometers in the Pacific 25 years ago. Then they checked at regular intervals what was crawling and floating there. Only after seven years could they report the same density of soil organisms again. However, some species never returned. This year the researchers want to look again. Even in the underwater mountains, which are sometimes damaged by trawls, there are fewer species than before 30 years after the destruction.

One of the demands of marine biologists is therefore: We need protected areas whose ecosystem is comparable to that of the mining parcels. Displaced species could settle there; unique animals would not completely disappear if their habitat was destroyed elsewhere. "If we know there are representative sanctuaries, we can mine," says Linwood Pendleton, an ecologist at Duke University. "If we're unsure, we shouldn't even start."

Another idea: raw materials should only be mined in small strips so that living beings at least have the chance to quickly colonize the devastated soil again from right and left. Nautilus Minerals also wants to relocate snails off Papua New Guinea, spread artificial substrate on the sea floor and renature part of the excavated area - while another part is to remain untreated for comparison purposes.

Expiring licenses, new regulations, first mining projects, environmental studies: “Everything will come together in the next three to five years. Then, hopefully, we'll know if deep-sea mining is feasible, ”says Geomar researcher Hannington. For Cindy Lee Van Dover, this sounds like an opportunity and a threat at the same time: Before the big money starts flowing, deep-sea research must deliver results - and these results must lead to sensible, well-considered regulations, the biologist demands. Afterwards it is too late.

"If we want to have really advanced regulation to protect the underwater environment, we have to act now," says Van Dover. "I want people to say a hundred years from now: Back then, based on the available scientific data, they set the right course - and didn't fall asleep at the wheel."

Source: Alexander Stirn, Goldgrund, Süddeutsche Zeitung, May 1, 2015

http://www.sueddeutsche.de/wissen/tiefseebergbau-goldgrund-1.2457954

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