The science behind mining for riches on the deep-sea floor

Subscribe to enjoy similar stories.Explorers have dreamed of harvesting deep-sea metals since the 1870s, when the British scientific ship HMS Challenger pulled up mineral-laden rocks on its round-the-world voyage.The first commercial effort to exploit these riches failed a century later. In 1970, a U.S.

company hoisted 60,000 rocks from the seafloor off the coast of Charleston, S.C., and then dumped most overboard because they didn’t have enough mineral content.Today, deep-sea mining—off-limits in international waters since 1982—has the backing of the Trump administration. Ocean scientists are racing to determine whether marine life can coexist with machines that rake their habitat for undersea treasure.The aim is to vacuum up rocks containing cobalt, nickel, copper and manganese—elements used in electric-vehicle batteries, smartphones, medical devices and artificial-intelligence hardware.The potato-size polymetallic nodules are found on vast flat areas of the seafloor called abyssal plains.

The most valuable region is a 1.7 million square mile part of the Pacific Ocean between Hawaii and Mexico known as the Clarion–Clipperton Zone.Other mineral deposits known as polymetallic sulfides collect around hydrothermal vents, fissures that discharge water from geothermal hot spots, while cobalt-rich crusts are found on underwater seamounts in shallower water.Last month, President Trump directed the National Oceanic and Atmospheric Administration to grant permits to mining companies in both U.S. and international waters over the objections of the International Seabed Authority.

The agency has legal authority over seabed resources under the U.N. Convention of the Law of the Sea, a 1982 treaty that has been signed by more than 160