Mitigation Mining Technology and Seabed Biodiversity

The Ocean bottom is the next frontier for both marine scientists and mineral miners. Since less than 15% of seabed have been mapped, we still have a great deal to learn about resources available deep underwater. But quite predictable environmental effects seem an obstacle.

In fact, we know more about Martian landscapes than about the floor of our Earth’s oceans. Water covers approximately 70% of the total Earth’s surface. The average depth of the world ocean of 3.7 km makes exploration of seabed technically challenging even in the 21st century. The Ocean waters protect deep sea treasures against greedy humans. Otherwise the whole seabed would be digged with mines and open pits long ago, most probably.

The present agenda of a transition to a battery-driven economy implies an exponential growth in demand for such battery metals as cobalt, copper, nickel, and manganese. Their onshore deposits are well-explored, and a predatory (in many cases) open-pit mining runs on full cylinders threatening a global economy to face a mineral shortage much sooner that it is expected — continental resources of valuable minerals are limited.

In their attempts to criticize not yet existing industrial seabed mining many marine environmentalists rely on a bitter experience of the destroyed natural landscapes onshore. Analogies commend themselves. However, wouldn’t it be jumping into conclusions when continental mining technologies with their monstrous machinery are juxtaposed with the ones designed for mineral mining at the sea floor?

Thanks to many-year collaborative efforts of the International Seabed Authority and numerous marine scientists we are fortunate to grasp the major fears dedicated to possible negative aftermaths of seabed mining with regard to marine biodiversity. Even though the research of numerous deepwater benthic creatures are far from being complete, we greatly appreciate the knowledge-abundant and consistent scientific reports represented during the Pew Side Event in Kingston (Jamaica) in February 2019 by professor Craig R. Smith, Dr. Eric Simon-Lledo, and Dr. Diva Amon.

Oversimplification is no good

Some people who stand far from the very intrigue of a seabed-mining challenge could keen to see the solution oversimplified: in order to avoid all negative effects of a deep-sea mining, the only things we need to do is expanding the so-called APEI (Area of Particular Environmental Interest) over the whole Ocean. Nobody can argue that keeping marine biosphere absolutely untouched is possible only when any human activity at the ocean bottom is prohibited.

(image credit: presentation of professor Craig R. Smith at the Pew Side Event in Kingston (Jamaica) in February 2019)

Such an environmental radicalism would be acceptable if exploitation of marine mineral resources implies no physical intervention in a deepwater environment. Exploration activities can in principle be limited to only observation of what is going on at the Ocean bottom. In contrast to it, extraction of minerals from the sea floor can hardly come down to just virtual missions. And the professional marine scientists who tightly work with the International Seabed Authority realize this well enough not to consider oversimplified solutions.

The whipping-boy misconception

In many cases, scientists tend to express their environmental concerns having just a hypothetical seabed mining technology before their eyes. Numerous illustrations available on the Internet represent it with the machines similar to those we used to seeing in the onshore open pits. The irony of a situation is in the fact that such mythical apparatuses became a bugaboo for technically inept environmentalists being the most convenient target for their critics at the same time. On the other hand, real images from the seabed where tracks from a trial nodule trawling are depicted have a history of two-three decades. It is hardly legitimate to accept them as an evidence of destructive practices inherent in any contemporary existing seabed mining technology.

Deepwater “elevators”

That’s why it is crucially important for marine activists to stop basing their attitudes on sorrowful biases that an eco-friendly underwater mining is technically impossible. Moreover, the current state of affairs around seabed mining leaves no chance to any destructive mining technology to start an actual operation at the ocean floor on an industrial scale. In order to get rid of obsolete myths, a really existing advanced eco-friendly technology is worth considering. It is represented by submersible miners designed by Krypton Group.

They use a motion principle similar to the one used to in submarines. The underwater movement is based on adjustable buoyancy when miners levitate over the seafloor without having to “land” on it. At its essence, such a miner is a submersible elevator capable of moving up and down within water layers. But in contrast to ordinary elevators, a Krypton’s miner can also move back and forth, left and right in any direction whether vertically or horizontally.

Positive buoyancy is a clue

The miners can dive to the ocean bottom using ballast water when its in-tank volume determines a position of an apparatus at a given depth. After reaching a definite distance (5–8 m) over the seabed, a miner starts collecting polymetallic nodules with a special mining tool. The miner’s positioning at a certain depths is regulated by both the weight of collected nodules and the volume of ballast water: the more nodules appear in a cargo bunker, the more water is pumped out from ballast tanks.

Nodules are the potato-sized pieces of ore through which seabed mineral resources are represented in most cases. They lay on the bottom being semi-immersed in mud. Once nodules have been forming at the seabed over centuries, they were always a part of a natural deepwater ecosystem where various benthic creatures inhabited in abundance.

(image credit: presentation of professor Craig R. Smith at the Pew Side Event in Kingston (Jamaica) in February 2019)

That’s why the second important question marine scientists always raise relates to methods of extraction of nodules. The thing is that numerous species of micro and macro flora and fauna live either directly on nodules or in a close proximity to them. Supposedly, small near-bottom inhabitants can be in danger appearing in cargo bunkers together with nodules.

Nothing but nodules

The task of careful extraction of nodules should be divided into several stages. Krypton’s engineers propose the following three steps:

1) When a miner is approaching the seafloor, special water blowers create an outgoing water stream towards the on-bottom nodules. Although the stream is not too intensive, it would be able to remove those deepwater species whose way of living does not imply strong symbiotic relationships with nodules;

2) An original design of a Krypton’s mining tool allows catching nodules with a special mechanical clamp made of strong thin strings through which anything other than nodules can easily slip. When bunkers are full, the ballast tanks get empty that provides a miner with a positive buoyancy making it surface at 5 km/h speed;

3) While surfacing, no highly mineralized near-bottom water can reach the surface since continuous exchanging of water layers in cargo bunkers occurs.

Of course, even a complex approach of Krypton to nodules’ collection can not provide a 100% guarantee that any benthic creature appears at the water surface. Especially it concerns such species as sponges, corals, and the similar deepwater organisms whose ecosystem includes nodules as an integral part. How to minimize a negative impact on both regeneration and biodiversity of such species will be discussed a little bit later when we come to a right mining strategy. Now, it is turn of yet another danger for the ocean ecosystem — sediment plumes and tailings.

Muddling is not destiny

Contamination of the ocean water with sediment plumes due to seabed mining is considered almost inevitable by many environmentalists. They suppose that since the bottom mud is a very fine-dispersed substance, a heavy miner will muddle the near-bottom water while moving over the seabed. This is another imaginary threat which takes place due to a wrong image of a deepwater miner. In fact, Krypton’s miners have no need to even touch the on-bottom mud once their adjustable buoyancy keeps them at a given distance from the sea floor.

The laboratory testing shows that the extraction tools can pick up nodules from the bottom in such a careful manner that quite insignificant muddling happens. In other words, whatever properties one or another bottom area has relating to mud, the given technology provides the least possible muddling ever.

“Tailings”?

Sometimes, such a mining term as “tailings” appears in a discourse of marine environmentalists. The very existence of tailings in a seabed mining process should imply something other than nodules appearing on the on-surface vessels in large quantities. As it was shown above, the “string” design of Krypton’s extraction tool allows to pick up only nodules from the bottom while anything else (mud and benthic organisms) remains at the seabed slipping through its strings.

The nodules delivered to the on-surface vessels will be subsequently processed onshore at the special separation and enrichment factories.

That’s why such word as “tailings” is unlikely relevant to seabed mining at all.

Conditions for “clean” seabed mining

Engineers at Krypton believe that in order to get rid of a problem of water contamination due to tailings and sediment plumes, the very preconditions of the problem should be eliminated. It means that both the mining technology and equipment used for it must provide a zero-contamination process when nothing is needed to be discharged back to the ocean. Such a process is possible if the following conditions are satisfied:

- Mechanical extraction tools are used for an accurate collection of nodules when a very gentle extraction with a special clamps provides the least possible muddling;

- Fully autonomous submersible miners capable of surfacing to deliver collected nodules to the on-surface vessels need no additional supply system;

- Cargo bunkers to where nodules are collected have a special semi-open design which provides continuous exchange of water layers when miners are surfacing.

Devastation is too challenging to be real

The last but not least problem appearing with regard to seabed mining relates to the totality with which miners seem to remove nodules from the ocean floor erasing the natural conditions for regeneration of the deepwater biodiversity. Many alarmed environmentalists suppose that a classical capitalist greed would make seabed mining enterprises extract every available nodule from a huge bottom area in their attempts to use deepwater deposits with a maximum economic efficiency. This is about a particular mining strategy which seemingly threatens to leave a life-less deepwater desert after seabed mining.

Such fears would be justified if quite specific working conditions of miners along with nuances of marine navigation were totally ignored. The thing is that water currents available both at the ocean surface and at depths make the task of a precise targeting a definite bottom area at 4–6 km depth extremely challenging in terms of navigation. In other words, the more total mining is considered the less feasible it occurs from both economical and organizational perspectives.

How a deepwater miner works

Let’s consider a hypothetical workflow of a single industrial miner from Krypton to understand why the purely economic factors would prevent it from covering a large bottom area with a total mining. The apparatus can collect up to 300 tons of nodules per a single dive.

It implies a back-and-forth movement of a miner over a piece of seabed where nodules should be collected. Once an average nodule content in the Clarion Clipperton Zone is 10 kilograms per a square meter, it is necessary to cover 30 000 m2 to fill in a cargo bunker of a miner completely.

In order not to go far away from a position where an on-surface vessel drifts, a miner will have to form a rectangular mining spot with approximate dimensions of 100 x 300 m. After filling in bunkers with nodules, a miner starts surfacing to deliver cargo to a processing vessel. The total time required for surfacing, bunker unloading, preparing for the next working shift, and subsequent diving to the bottom again can last 4–5 hours.

Why drifting helps

During this period, both a miner and an on-surface vessel will be drifted quite far from the point of a previous dive due to available ocean currents. In order to get back closely to a previous mining spot (100 x 300m), a lot of navigational efforts should be made that implies quite intensive sailing with complicated positioning that, in its turn, implies significant extra costs — fuel, time, labor etc. The question is: why should a miner pursue a precise positioning towards a previous mining spot if a licensed mining area covers 75 000 square kilometers?

There is always enough space in such a huge seabed area to collect nodules over centuries (!) without having to return to the same place twice. The very economic feasibility will prevent miners from a total devastating of wide fields at the ocean floor. A distance between two neighboring mining spots can be hundreds if not thousands of meters when the described “drifting” workflow is used. Hence, the very cost-effectiveness of a mining process will determine quite a chaotic and, therefore, regeneration-friendly mining strategy allowing such species as, for example, sponges to survive and regenerate even beyond APEIs.

Once submersible miners can work accounting both on-surface and in-depth water currents, every mining spot can be precisely mapped. The bottom mining areas, therefore, can be covered with the processed spots in a random mode while deepwater species will have enough “empty” non-processed areas for adaptation and reproduction.

Calculations matter

Fear has magnifying eyes, as they say. That’s why a calculator in hands along with a simple statistics can help marine activists address many ambivalent issues from a different angle. How devastating for the World Ocean is an annual production plan of Krypton Group, for example? It implies 1 million tons of nodules per a year and it sounds creepy without a reference to both the entire seabed surface and the amount of mineral resources available there. A single licensed piece of seabed in the CCZ having 75 000 km2 area contains approximately 350 000 000 tons of nodules (underwater mountains and trenches available there don’t account) that is enough to make Krypton busy for… well, 350 years!

At the same time, such an area constitutes only about 0.02% of the total seabed surface. Hence, two hundredths of a percent of the total ocean floor can actually provide dozens of mining companies with work for hundreds of years. Can this proportion provide sufficient time and space for regeneration of deepwater species? It seems so, but the marine scientists should check and verify this data.

Need to prepare in advance

Some may argue that although given explanations sound convincing, an actual mining practice may differ a lot in fact. Of course, projects differ from prototypes, and prototypes differ from serial equipment. But project designing should initially take many environmental aspects into consideration to reach goals in a systematic way.

The International Seabed Authority invites numerous marine scientists to participate in the development of a seabed mining code before an industrial-scale mining starts in the ocean. This is the only wise approach to mineral extraction in the days when the humanity is looking for sustainable eco-friendly solutions able not to replicate the predatory practices still available in the onshore mineral mining. Similarly, the development of seabed mining technologies should include eco-friendly approaches at the very initial stage. Besides, Krypton Ocean Group believes that the most eco-friendly technology of seabed mining happens to be the most economically feasible one.

Collaboration is required

Marine environmentalists should collaborate with mining technologists in the field of seabed mining since their opposition can lead to nothing but harm for the oceans. The World Ocean belongs to what is considered a heritage of the whole humankind. But we still live in the world which is homogeneous neither in politics nor in economy. A total ban on seabed mining from the UN can hardly guarantee that at any moment in the future it can be violated by some State whose political and economical desires and ambitions imply exploitation of marine mineral resources beyond any supranational control. If no eco-friendly technology is available at that moment as an exemplary international practice, such a State could use a different much more destructive one. That’s why hiding head in the sand can never help marine activists protect biodiversity of the oceans. Only collaborative efforts of technology providers and environmentalists rather than strict prohibitions can offer our new green economy valuable battery minerals from the seabed without affecting ocean biodiversity.