Mining the ocean floor is about to go mainstream

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Mining the ocean floor is about to go mainstream

Mar 8th 2018

 

 

PATANIA ONE sits in a large shed on the outskirts of Antwerp. Green and cuboid, with an interior steel frame, rubberised treads and pressure-resistant electronic innards, it is about the size of a minivan. In May 2017 it became the first robot in 40 years to be lowered to the sea floor in the Clarion Clipperton Zone (CCZ), about 5,000 metres beneath the Pacific ocean near where the Jasper did her pioneering sonar work. There it gathered data about the seabed and how larger robots might move carefully across it, sucking up valuable minerals en route.

The CCZ is a 6m square-kilometre (2.3m square-mile) tract between two of the long, straight “fracture zones” which the stresses of plate tectonics have created in the crust beneath the Pacific. Scattered across it are trillions of fist-sized mineral nodules, each the result of tens of millions of years of slow agglomeration around a core of bone, shell or rock. Such nodules are quite common in the Pacific, but the CCZ is the only part of the basin where the International Seabed Authority (ISA), which regulates such matters beyond the Exclusive Economic Zones (EEZs) of individual countries, currently permits exploration. Companies from Japan, Russia, China and a couple of dozen other countries have been granted concessions to explore for minerals in the CCZ. The ISA is expected to approve the first actual mining in 2019 or 2020.

Shock and ore

This could be big business. James Hein of the United States Geological Survey and colleagues estimated in a paper in 2012 that the CCZ holds more nickel, cobalt and manganese than all known terrestrial deposits of those metals put together. The World Bank expects the battery industry’s demand for these, and other, minerals to increase if the transition to clean energy speeds up enough to keep global temperatures below the limits set in the Paris agreement on climate.

One of the firms attracted by this vast potential market is DEME, a Belgian dredging company which has already proved resourceful in seeking out new businesses: installing offshore wind farms now provides it with revenues of nearly €1bn ($1.2bn) a year. Korea, Japan and China all have state-run research projects looking to dredge nodules from the deep sea with robots: “It really is a race,” says Kris Van Nijen, who runs DEME’s deep-sea mining efforts. At the moment his firm is setting the pace. It has learned a lot from the exploits of Patania One (pictured), such as how hard you can push bearings rated to 500 atmospheres of pressure and how deep treads sink into the deep-sea ooze for a given load.

The idea of mining the CCZ is not new. The Pacific’s mineral nodules were discovered by HMS Challenger, a British research vessel that first dredged the abyssal depths in the 1870s. Lockheed Martin, an American defence contractor, tried prospecting the CCZ in the 1960s. Its caterpillar tracks were not reliable enough to operate at such depth, so the company imagined two Archimedes screws to drag its vehicle through the mud. (Lockheed’s deep-sea mining expertise was later used in a CIA operation to recover a Soviet submarine which sank in the CCZ in 1968.) At the time there was hyped speculation that deep-sea mining would develop rapidly by the 1980s. A lack of demand (and thus investment), technological capacity and appropriate regulation kept that from happening. The UN Convention on the Law of the Sea (UNCLOS), which set up the ISA, was not signed until 1982. (America has still not ratified it, and thus cannot apply to the ISA for sea-floor-mining permits.)

Mr Van Nijen and his competitors think that now, at last, the time is right. DEME is currently building Patania Two, or P2, in an Antwerp shipyard. It will be deployed to the Pacific in 2019. Where P1 was basically a deep-sea tractor, P2 is a full-blown prototype. A sweeping nozzle mounted on its front (which gives it the look of a combine harvester) will suck up tonnes of nodules every minute; the power it needs to do so will flow down a thick umbilical from a mother ship above. In commercial production, a similar cord will pump a slurry of nodules and dirt back up to the ship—an impressive bit of engineering. For the time being P2 will just keep some of the nodules in a container on its back for later inspection.

In order to satisfy the ISA, this new machine does not just have to show it can harvest nodules; it also has to show that it can do so in an environmentally sensitive way. Its harvesting will throw up plumes of silt which, in settling, could swamp the sea floor’s delicate ecosystem. A survey of CCZ life in 2016 found a surprising diversity of life. Of the 12 animal species collected, seven were new to science. To help protect them, the mining field will be ringed with buoys, monitoring any plumes of silt that are bigger than DEME had predicted. The operations will also be monitored by a German research ship, funded by the EU.

If P2 succeeds, it will be time for P3, which will be the size of a small house. It will have two drone escorts, one to move ahead of it and one behind. They will monitor how much silt it disturbs, and will shut down the operation if necessary. Thus, P3 will be able to steer along the seabed autonomously. DEME will then build a customised surface vessel, ending up in about 2025 with a new kind of mining operation, at a total cost of $600 million.

The CCZ is not the only sea floor that has found itself in miners’ sights. Nautilus, a Canadian firm, says it will soon start mining the seabed in Papua New Guinea’s EEZ for gold and copper, though at the time of writing the ship it had commissioned for the purpose sits unfinished in a Chinese yard. A Saudi Arabian firm called Manafai wants to mine the bed of the Red Sea, which is rich in metals from zinc to gold. There are projects to mine iron sands off the coast of New Zealand and manganese crusts off the coast of Japan. De Beers already mines a significant proportion of its diamonds from the sea floor off the coast of Namibia, although in just 150 metres of water this is far less of a technical challenge.

If the various precautions work out, the benefits of deep-sea mining might be felt above the water as well. Mining minerals on land can require clearing away forests and other ecosystems in order to gain access, and moving hundreds of millions of tonnes of rock to get down to the ores. Local and indigenous people have often come out poorly from the deals made between miners and governments. Deep-sea mining will probably produce lower grade ores, but it will do so without affecting human populations.

It will also deliver those ores straight on to ships which can move them directly to processing plants on any coast in the world, including those using solar or wind power, thus reducing the footprint of mineral extraction even more. Having seen the destruction wrought by mining on land, undersea miners are working doubly hard to plough a different furrow.

 

Source:  https://www.economist.com/news/technology-quarterly/21738059-mining-ocean-floor-about-go-mainstream-race-bottom