Seafloor Mining

From Beachapedia

The following article was originally adapted from an article Seafloor Mining on the website of Woods Hole Oceanographic Institution, as well as an article from The Promise and Perils of Seafloor Mining, published in Oceanus Magazine, November 20, 2009. Updates continue to be made as new policies and studies become available. Seafloor mining is also sometimes referred to as Deep Sea Mining.

What is Seafloor Mining?

The ocean hosts a complex combination of physical, chemical, biologic, and geologic processes that sometimes result in commercially viable forms of a wide range of minerals. This is particularly true in areas around hydrothermal vents, where hot, chemical-rich fluids pouring up from beneath the seafloor produce potentially valuable deposits. A few efforts to mine deposits on the seafloor have succeeded, but to date, not many have overcome the technical challenges involved in retrieving tons of raw materials from a few tens to thousands of feet beneath the surface of the ocean.

Some successful mining has already occurred in relatively shallow waters. In the 1960s, Marine Diamond Corp. recovered nearly 1 million carats from the coast of Namibia. Today, de Beers obtains a significant portion of its total diamond production from the continental shelf of southern Africa, in water shallower than 300 meters (1,000 feet). Mining operations in deeper waters have led to a very different results: When investors tried about 40 years ago to retrieve potato-sized manganese nodules scattered on the ocean floor, almost half a billion dollars worth of prospecting couldn’t make their efforts profitable.


Since then, the mining industry has been working to develop specialized dredgers, pumps, crawlers, drills, platforms, cutters and corers, many of them robotic and all designed to work in the harsh conditions of the deep ocean. In addition, increases in the price of many materials such as copper, plus increasing demand from emerging economies is making such ventures more economically feasible. Recent discoveries of rich deposits on the seafloor and advances in technology are generating renewed interest in seafloor mining, including more diamonds, iron sands, cobalt-rich manganese crusts, phosphorite nodules and even those problematic manganese nodules. The rising importance and increasing scarcity of rare earth elements is also making some take a new look at the possibility of refining these materials from seafloor sources.

Most attractive of all for the mining industry are the potential riches at deep-sea hydrothermal vents. Known for nourishing lush communities of exotic life, the vents also can be treasure troves of high-grade minerals. When the very hot, chemical-rich fluids that spout or seep from the vents meet the cold water of the ocean, dissolved minerals solidify from the fluids and billow into the water or fall onto the seafloor or build up into massive chimney-like structures. These chimneys appear to billow black or white “smoke” depending on the chemical makeup of the fluids. Many sulfide deposits on land likely were formed the same way and were later were raised above sea level during the formation of islands and continents over millions of years. The island of Cyprus, for example, holds 30 massive sulfide deposits, which were a main source of copper for ancient Rome.

Hot, buoyant, mineral-laden fluids rise from deep within ocean crust and mix with cold seawater. That triggers the precipitation of minerals that form deposits near and on the seafloor. Precipitating minerals also form seafloor "chimneys," and mineral particles in the fluids venting at the seafloor make the fluids look like smoke. These chimneys are at a vent site that scientists called "Roman Ruins," in the eastern Manus Basin in the Bismarck Sea south of the island of New Ireland in Papua New Guinea. (Photo courtesy of Maurice Tivey and WHOI Deep Submergence Lab, Cruise Manus 2006 with ROV Jason, Woods Hole Oceanographic Institution)

For a number of reasons, the mining industry’s interest in seafloor massive sulfides is focusing mostly on vent fields in the western South Pacific. Many of the vent fields are located within the exclusive economic zones of small island nations, eliminating the potential complications of mining the seabed that lies under international waters. Many hundreds of thousands of square kilometers of the region’s seafloor have been leased for exploration and mining could begin soon off the coast of Papua New Guinea. More on this from The Ocean Foundation, who are part of a coalition of NGOs concerned about environmental impacts of the project, and Nautilus Minerals, the project proponent.

Meanwhile, US-based military contractor Lockheed Martin is negotiating licenses for the exploration of poly-metallic manganese nodules with the Fiji administration. The company’s UK subsidiary UK Seabed Resources has its eyes on similar nodules in international waters spanning 58,000 km2 between Hawaii and Mexico.

Off the West Coast of New Zealand, Trans-Tasman Resources (TTR) applied to New Zealand Petroleum and Minerals in May 2015 for a prospecting permit covering a 4436-square-kilometer area which spans a huge section of coastline, from Ross to Karamea. Should it apply to go ahead with mining, TTR will not go through the Environmental Protection Authority (EPA) for a marine consent because the proposal would be within 12 nautical miles of the coast.

The Good

Seafloor mining has the potential to help meet demand for many minerals used worldwide and could help bolster the economies of developing nations in one of two ways. The mining could take place in a nation’s own exclusive economic zone, or it could take place on the seafloor under international waters, where the International Seabed Authority dictates that a portion of all mining profits benefit developing nations.

The Bad

Potential impacts from Nautilus Minerals seafloor mining project near Papua, New Guinea (Nautilus Minerals, Inc.)

However, seafloor mining also has the potential to take a toll on the life in the sea. Anytime the seafloor is disturbed, so too are its fragile ecosystems—though the mining industry maintains that it is using and developing environmentally sensitive techniques, and many ocean habitats often appear to recover from damage. At the same time, the interest in mining is helping scientists study both the oceans’ chemistry and clues about how the planet formed.

Biologists are particularly concerned about the potential for mining to disrupt or destroy unique communities of exotic life forms, such as those at hydrothermal vents and seamounts. The result could be the subsea equivalent of replacing an old-growth forest with a field of dandelions. On the other hand, animals similar to those that originally inhabited the vent site could eventually return. Too little research has been conducted to know for sure.

The argument for protecting species is the same as that on land—diversity is at the heart of functioning ecosystems; it helps life adapt to changing conditions.

No two vents discharge exactly the same mixes of fluids, so no two vents are colonized by exactly the same life forms. Researchers continue to find new vent species just about every time they look for more. What each deep-sea vent ecosystem has in common are conditions that would be incredibly hostile to most other life: extremes of temperature, intense ocean pressure, hot acidic fluids. Yet they foster rich communities, including extraordinary microbes that harness energy from chemicals rather than from sunlight as plants do. These strange life forms may hold clues to how life started on Earth. So little is known about them that if vents are mined, we may never know what species have been lost.

Environmental advocates are also concerned about the safety of whole systems planned for recovering the minerals--including boats, barges, and heavy equipment that could accidentally pollute local waters and shorelines with fuels, other industrial chemicals and oxidizing ores. One effort to combat this possibility was led by the industry-led International Marine Minerals Society, which in 2010 implemented a voluntary code for environmental management.

This article in Yale's Environment 360 publication summarizes the environmental concerns with seafloor mining.

In July 2015 an article Managing mining of the deep seabed was published in Science Magazine. The authors, headed by University of Hawaii oceanography professor Craig Smith, recommend the International Seabed Authority take a precautionary approach and set up networks of marine protected areas before additional large claims are granted. Scientists and others fear mining impacts could threaten environmental benefits that the deep sea provides to people, like capturing human-emitted carbon which impacts both weather and climate. More on this.

Five years later, in July 2020, University of Hawaii researchers released a "researched opinion piece" continuing to warn of large-scale and widespread environmental and ecological impacts from seabed mining, citing issues to individuals, populations, and entire ecosystem services.


In September 2015 the Deep Sea Mining Campaign released a statement that read, in part:

"...a new critique by the Deep Sea Mining Campaign reveals indefensible flaws in the Environmental and Social Benchmarking Analysis of the Solwara 1 project commissioned by Nautilus Minerals. The proposed Solwara 1 deep sea mine, situated in the Bismarck Sea of Papua New Guinea, is the world’s first to receive an operating licence.

Endorsed by a coalition of economists, scientists and civil society groups, the critique entitled Accountability Zero, will be launched by Professor Richard Steiner during his presentation at the Summit today (September 29).

“By using metrics that bear no relevance to deep sea and marine environments, the Solwara 1 ESBA values at zero the ecosystem goods and services provided by deep sea and marine ecosystems.” said Francis Grey, Founder of Economists at Large and co-author of Accountability Zero. He continued, “Fundamentally, the ESBA report fails to meet the well accepted requirements of a cost-benefit analysis. It is of little value to public policy and deep sea mining (DSM) decision-making..."

In February 2017 an article was published at Motherboard which referenced an article in Science An ecosystem-based deep-ocean strategy in which an international group of marine scientists outlined the desperate need for an international effort to regulate the ocean floor. The Motherboard article stated that the first deep sea mining site, Solwara-1, located off the coast of Papua New Guinea, will likely begin operations in late 2017 or early 2018 to extract gold, zinc, silver and copper from the ocean floor. Over the past decade, more than 1 million square kilometers of seabed has been earmarked for mining operations.

Who Regulates Seafloor Mining?

The rules that govern mining on most of the world’s seabed are no ordinary rules. They got their start back in the 1970s and 1980s, when it looked as if there were untold riches in manganese nodules scattered across the ocean floor.

Although that didn’t pan out, mining companies and nations around the world are eyeing anew the riches of the deep. The more recent discovery of metals at hydrothermal vents rekindled interest in the seabed, said Porter Hoagland of the Marine Policy Center at Woods Hole Oceanographic Institution (WHOI). “Technology makes it more possible, and the economics make it more likely.”

To regulate seafloor mining, in 1994 the United Nations Convention on the Law of the Sea spawned the International Seabed Authority, or ISA, an independent treaty organization. It has jurisdiction over the seabed outside the exclusive economic zones that surround nations’ shorelines—an area it efficiently calls "The Area." The term refers only to the seafloor, not to the waters above it (they’re called the “high seas” in legal parlance). The rules dictate that the ISA make licensing decisions and, remarkably, that a portion of all profits from mining in The Area be used to benefit the world’s developing countries.

An ISA working group—which includes academic, government, and industry experts for advice on environmental and economic issues—is developing specific regulations, said ISA Secretary-General Nii A. Odunton. “But we could use the international science community to get more information,” he told a gathering of almost 100 scientists from 20 countries and other seabed mining stakeholders at a conference in April 2009 at WHOI. “The more we can get scientists to help us get the information we need, the better we think our regulations will be.”

The ISA has 159 member nations. The United States is not one of them, because it has not ratified the Law of the Sea treaty, though it has “observer” status. Political conservatives have successfully blocked the move so far, even though President George W. Bush in 2007 urged the Senate to approve the agreement. Former U.S. Secretary of State Hillary Clinton made clear that U.S. ratification of the treaty is a priority for the Obama administration. The new ISA regulations are expected to open up The Area to commercial prospecting for seafloor minerals.

Without US federal plans or protections in place, coastal states are starting to take action to prevent seafloor mining in state waters. In 1991, Oregon was the first to prohibit seabed mining. As the threat of potential seabed mining increases in the Pacific, other West Coast states followed suit banning the practice in state waters, including a ban in Washington in 2021, a ban in California in 2022, and recently, a ban in Hawaii in 2024 (just awaiting governor signature to become law).

Seabed mining infographic PEW.jpg

Seabed Mining. A call to action graphic by The Pew Charitable Trusts.