Marta Montojo and Ian Urbina from the non-profit Outlaw Ocean Project on the risks of dredging minerals from the ocean floor.

Few people have ever heard of the tiny country of Nauru. Even fewer ever think about what happens at the bottom of the world’s oceans. But that may soon change. The seafloor is thought to hold trillions of dollar’s worth of metals and this Pacific-island nation is making bold moves to get a jump on the global competition to plumb these depths.

The targets of these companies are potato-sized rocks that scientists call polymetallic nodules. Sitting on the ocean floor, these prized clusters can take more than three million years to form. They are valuable because they are rich in manganese, copper, nickel, cobalt that are claimed to be essential for electrifying transport and decarbonizing the economy amid the green technological revolution that has emerged to counter the climate crisis.

To vacuum up these treasured chunks requires industrial extraction by massive excavators. Typically 30 times the weight of regular bulldozers, these machines are lifted by cranes over the sides of ships, then dropped miles underwater where they drive along the seafloor, suctioning up the rocks, crushing them and sending a slurry of crushed nodules and seabed sediments from 4,000-6,000 meters depth through a series of pipes to the vessel above. After separating out the minerals, the processed waters, sediment and mining ‘fines’ (small particles of the ground up…

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