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The Case for Deep-Sea Mining

April 17, 2023 Deep sea

At this year’s Cleantech Summit, Deep Sea Mining is on the agenda for both speakers and panelists. For many, the term “mining” often elicits fear and anger. Mine tailings and deforestation are two of the enormous planetary costs of mining metals from the ground. But what if there was a different way to obtain these minerals, one that did not create so much waste and damage fragile ecosystems?

Recently, I had the privilege to interview Erica Ocampo, The Chief Sustainability Officer at The Metals Company (TMC). She has held similar positions for almost twenty years, including 12 years at DOW as the Global Sustainability Strategy Manager. During her interview, she explained to me how she came around to the idea of deep-sea mining, why she believes it deserves to be considered by those who are environmentally conscious, and how TMC is achieving this.

For Ocampo, coming around to the idea of deep-sea mining was challenging. She explained how, like others who are passionate about the environment, she has the desire to protect and preserve our planet. She said that we have “to come to the realization or acceptance that everything that we do on the planet has an impact.” Just how big is the impact? Regardless of whether they are mined on land or in the deep sea, metals are crucial to everyday life and the energy transition. Because of their importance in our world, finding a way to obtain metals without destroying large carbon sinks or creating huge mine tailings is necessary. TMC presents a considerable alternative through deep-sea mining of polymetallic nodules.

What is Deep Sea Mining?

As with mining on land, a variety of mineral deposits are found in the deep sea, which have varying impact profiles. According to TMC, the “collection” of polymetallic nodules off the ocean floor is unlike other seabed mineral types which required hard rock cutting and drilling. Polymetallic nodules are potato-sized rocks sitting on the ocean floor 4-6 kilometers deep. These nodules have high concentrations of nickel, manganese, cobalt, and copper, which are all major components of batteries and can be used without producing waste. These nodules are collected without drilling or blasting, therefore avoiding the deforestation and mine tailings that accompany mining on land. TMC’s model of collecting the nodules includes a robot tethered to the ship, which shoots water underneath the nodule to dislodge it, and then sends the nodule up to the ship through a pipe.

What is the impact?

Due to their depth of 4-6 kilometers, the nodules sit on the abyssal plain of the ocean floor. At this depth, there is very little light, high pressure, low temperatures, and little food available, thus 70% of life in this ecosystem exists in the form of bacteria. Additionally, TMC has made significant efforts to reduce its environmental impacts as far as possible by determining how to mitigate the sediment plumes that occur when nodules are taken up, and how to redistribute the water in the water column.

Once collected, the nodules are transported back to land for processing. TMC plans to construct an area where they can base their on-land production, one combining both pyrometallurgical hydrometallurgical processing the nodules. The overall goal of TMC is to be a metal recycling company, but the first step is to build enough stock of metals. Ocampo estimated that it may take 20- 50 years for enough stock to build for recycling to be a significant supply of these metals, but TMC is committed to its goal of recycling metals to ensure sustainability.

Where and when is this happening?

The area in question is the Clarion-Clipperton Zone (CCZ), which is approximately 1.2% of the ocean, west of Mexico and southeast of Hawaii. The area is governed by the International Seabed Authority (ISA), which was created by the United Nations in 1994. The ISA is made up of 167 member states and the European Union. The United Nations Convention of the Law of the Sea Treaty (UNCLOS) in 1982 determined where national waters were and set in place the ISA. Already, 43% of the CCZ has been set aside for conservation by the ISA. For anyone to mine in the CCZ, they must be sponsored by a member state, and apply for exploration and commercial contracts. TMC currently has three exploration contracts sponsored by the Republic of Nauru, the Kingdom of Tonga, and the Republic of Kiribati. TMC is currently in the process of applying for an exploitation contract from the ISA which allows them to collect and process nodules commercially.

This past year, TMC completed its Pilot collection in 2022, which allowed them to test their nodule retrieval methods and collect data on its environmental impact. TMC hopes to submit its exploitation contract application by the end of 2023 and hopefully begin small-scale production as early as late 2024.

Why Deep-Sea Mining?

Our world needs metals. Computers, iPhones, electric cars, and batteries all use metals. The electrification of vehicles requires a significant number of batteries which requires multiple tons of metals. Even if the United States does not mine these metals, other countries will, creating an increased dependence on foreign nations. Trees will continue to be flattened and land poisoned by tailings because the demand for the metal is only continuing to grow. The question then becomes: where will all this metal come from?

While deep-sea mining could sound concerning, polymetallic nodules present a significant way to obtain metals with the potential to dramatically reduce the impacts on the environment. The nodules’ depth ensures very little life is disturbed. The care and intentionality of TMC guarantee that every step is documented and does the least damage possible. The technique of grabbing the nodules allows for little sediment to be disturbed. The nodules themselves contain all the crucial metals needed for batteries. While the entire process is not yet carbon-free, it is taking steps to be. Polymetallic nodules are miniature batteries, sitting unattached to the abyssal plain at 4-6 kilometers deep, waiting to be gathered and used to help solve the metals crisis.

When considering deep sea mining, Ocampo had this to say: “What I have learned is that anger and fear are two emotions that I recommend any environmentally conscious individual to move away from as they are not constructive. Often, we fear what we do not know or understand. So to me, I would instead like to invite all the change agents out there that are deeply committed to making a positive impact in the world, to stay humble and curious. Because we are at a point in history where difficult choices lie ahead of us, but inaction is not an option. So stay humble. Consider all the options and be curious enough to dive into the facts and these conversations are a good start.”

Deep-sea mining is a viable option for obtaining metals. The world will continue to consume metals, so finding a way to minimize environmental costs while collecting these metals is an important problem we need to solve. Deep-sea mining presents a way to obtain metals with a potentially much smaller impact on the surrounding environment.

Erica Ocampo was a panelist at the UNC Cleantech Summit on March 23-24, 2023.

About the Author

This article was written by Chandler Deese, a first-year honors student at UNC-Chapel Hill studying Environmental Science and Geology. She is an IE Cleantech Intern involved with the Battery Minerals and Supply Chains and Deep-Sea Mining panels.