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The next frontier: mining the sea floor

Two miles down on a seafloor strewn with chimney-like accretions that spew a black plume of super-heated chemical soup, life exists. Tube worms 7 feet long have colonized here, along with tiny translucent octopuses, giant clams and shrimp dining on bacteria that produce energy not by photosynthesis but chemosynthesis in this light-starved, chemical-rich environment.

This is the surreal world of hydrothermal vents, where seawater meets magma deep within the Earth’s crust and spews back out onto the seafloor, and supports a unique and particularly vulnerable community of undersea life. The mineral-laden water also leaves sulfide deposits rich in cobalt, gold, copper, zinc and rare earth elements, much coveted by mining companies that are working to develop technology to operate 10,000 feet and deeper beneath the surface.

This summer, as the first deep-water mining project was ramping up for a 2018 launch, the International Seabed Authority, an autonomous international organization set up under the 1982 United Nations Convention on the Law of the Sea, was meeting in Jamaica to formulate rules for governing deep-sea mining in international waters. This rules-making meeting — along with the eagerness of mining companies to exploit the ocean’s deep-water resources — has generated opposition among critics who say deep-sea mining will irreversibly damage the seafloor and snuff out an ecosystem that is barely understood and only partially identified.

“Far too little is known about the potential impacts of deep-sea mining on our oceans, reefs, marine life and fisheries,” says Payal Sampat, of Earthworks, a non-profit that seeks to protect communities and the environment from mining and oil operations. The group also is a member of the Deep Sea Mining Campaign, which is advocating protection of the Pacific seafloor from deep-sea mining. “Many of these marine organisms haven’t even been discovered, let alone studied,” she says. “Deep-sea mining is a high-risk, experimental industrial activity being proposed in one of the most fragile, unexplored areas of our planet.”

Earthworks and a half-dozen other conservation groups have called for a 10-year moratorium on deep-water mining to allow scientific understanding of the life and geology of the seafloor to catch up with mining technology. “Clearly, the science is not anywhere close to sufficient,” says Richard Steiner, a conservation biologist, founder of the Oasis Earth environmental consultancy and one of the leaders in the Exxon Valdez oil spill response.

Steiner says mining companies are eyeing three types of mineral deposits on the deep ocean seafloor. One is 1,500- to 5,000-meter-deep sulfide deposits found around hydrothermal vents near underwater volcanoes and tectonic plate boundaries. These deposits contain high concentrations of copper, gold, silver, zinc, cobalt and rare earth metals. Seawater seeps down deep through cracks and fissures in the ocean floor to volcanic magma, where the water heats to a boil, rises back to the ocean floor and on the way up dissolves minerals and chemicals in the rock. This creates a dark chemical brew that mixes with near-freezing seawater on the sea bottom and releases some of the minerals in precipitates that harden along the vent’s edges.

Nautilus Minerals, a Canadian company and the first to attempt deep-water mining, is scheduled to begin mining hydrothermal deposits in the territorial waters of Papua New Guinea for copper and gold in 2018. Nautilus says the copper grade of the deposits is 7 percent, compared with 0.6 percent for land-based mines, and an average 6 grams a ton for gold.

A scientist shows one of the deposits that miners want to extract.

Another undersea deposit drawing mining interest is polymetallic nodules, also called manganese nodules. These potato-size metal nodules are found at 4,000 to 6,000 meters on the flat abyssal plain lying between the continental rises and midocean ridges. The deposits are rich in manganese, nickel, cobalt, copper, lithium, molybdenum, iron and rare earth elements.

Thirteen national consortia hold exploration leases on 4.5 million square kilometers of seafloor between the Mexican Baja and Hawaii, Steiner says. The United States, which is not a party to the Convention on the Law of the Sea or the International Seabed Authority, has issued exploration leases to Ocean Minerals Co., a subsidiary of defense contractor Lockheed Martin, to explore for nodules in that region of the Pacific.

A third geological formation of interest is ferromanganese crusts, which are rich in cobalt, nickel, copper, iron, manganese and rare metals such as tungsten, platinum, bismuth and tellurium and are found on summits and flanks of seamounts at depths of 400 to 4,000 meters. Many of these crusts are found in the exclusive economic zones that extend as far as 200 nautical miles off the Federated States of Micronesia, the Marshall Islands, Hawaii, Johnston Atoll and in international waters of the tropical Pacific, Steiner says. China and Japan are exploring crusts in international waters of the western tropical Pacific.

Nautilus Minerals’ illustrations of its proposed mining operations off Papua New Guinea show remotely controlled cutting and collecting machines four to five times the height of a man working the seafloor, much like giant earth movers working strip mines on land. The cutters excavate the seafloor with enormous rotating cutting heads, leaving cut ore (sand, gravel and silt) for a collecting machine to suck up in a seawater slurry. The slurry is pumped thousands of feet up a pipe to a support vessel, which dewaters the slurry and transfers the material to a vessel for transport to shore.

Steiner says much of the deep-sea mining technology is derived from the offshore oil and gas drilling industry and not ready for deployment. “Industry experts say that the technological readiness level for some kinds of [deep-sea mining] on a scale of 1 to 10 — 10 being highest readiness — is today only at about 3 to 4,” he says. “In other words, for most projects, the technology is nowhere near [ready].”

He says the ecosystems of the deep, where there’s no light, are fragile. “Deep-sea ecosystems are truly unique [because of the] nature of the deep-sea environment,” he says. The sea life there isn’t found anywhere else, grows slowly, has a low reproductive capacity and is threatened, he says, because we have a poor scientific understanding of it. It’s highly sensitive to human disturbance, subject to growing industrial interest, poorly protected and managed, and out of public view. “The risks are significant, and many remain unknown,” Steiner says. Among those risks is the extinction of some species and gene pools, he says.

The deposits are rich in cobalt, gold, copper, zinc and rare earth elements.

The Pew Charitable Trusts, which is working with the International Seabed Authority to develop “strong, science-based rules” for deep-sea mining, says most of the international seabed remains uncharted, and 55 percent of the world’s ocean floor lies outside any national jurisdiction. For the 167 member states of the ISA, seabed mining beyond national jurisdictions can take place only under contract with the organization.

The ISA has awarded 24 exploration contracts to members or their designees to survey possible mining areas in international waters, but it won’t be issuing any mining contracts until it finishes writing its regulations for actual mining.

“ISA is developing its first-draft regulations for mining development,” Steiner says. “It has had regulations for [deep-sea mining] exploration for years, but it is at this time developing the regulations for actual mining,” specifically nodule mining in the Pacific.

Giant tube worms, which can grow as long as 7 feet, colonize near hydrothermal vents on the sea floor.

“We are concerned that the ISA process is being driven by industry and government supporters without adequate scientific and civil society oversight,” he says. In addition to the moratorium on mining, he and others also are advocating the designation of more Marine Protected Deep Sea Areas where mining would be prohibited.

In May 2015, the Center for Biological Diversity sued the National Oceanic and Atmospheric Administration for renewing two permits for Lockheed Martin’s OMCO Seabed Exploration to explore for polymetallic nodules on tracts of deep-ocean floor between Mexico and Hawaii. The center challenged the permits on grounds that NOAA failed to ask the company to first submit environmental impact studies under U.S. law.

“Like mountaintop-removal coal mining, deep-sea mining involves massive cutting machines that will leave behind a barren landscape devoid of life,” Emily Jeffers, the lawyer who filed the case in federal district court in Washington, D.C., said at the time.

Advising ISA to adopt a go-slow policy in developing a regulatory regime for deep-sea mining, Earthworks’ Sampat says the “ISA cannot allow companies and governments to experiment with our global commons. It must promote research, oversight and protection of our deep ocean environments.”

This article originally appeared in the September 2016 issue.