Our growing society is ever more dependent on technology, which has resulted in a huge demand for metals such as copper, manganese, cobalt, and other rare earth minerals. Some of these are increasingly scarce and sooner or later conventional mining will not be able to meet demand. Thus, companies are taking more drastic measures to find these precious metals and the hefty price tag is becoming progressively feasible as the industry for deepsea mining is getting closer to realisation.

As the demand for the aforementioned metals, the same metals found in polymetallic nodules deposits, grows, companies have not only been researching the feasibility of deepsea mining, but also began designing and testing the technology to do so. Due to this, several parties have al­ready obtained contracts for the exploration and development of technologies to extract nodules of the seafloor governed under international regulations. In the following paragraphs, a general overview of environmental issues will be discussed as well as the regulations that will be put into place to ensure the protection of the marine environment. Not only this, but the technical difficulties will also be discussed along with the next steps the industry needs to take to make deepsea mining a reality.


Deepsea mining can either take place inside a country’s EEZ (Exclusive Economic Zone) or outside areas of national jurisdiction. Until now, only a few countries, most notably New Zealand and Japan, have created legal frameworks for deepsea mining. Japan has had the first successful test extraction in collaboration with JOGMEC in which 649 kilos of polymetallic nodules were collected. This successful test took place aboard the research vessel Hakurei in July 2020 in the test area around Takuyo No.5 Seamount. According to research, this area has both enough nickel and cobalt to meet Japan's needs for twelve years.

All other mineral resources that are outside of a countries EEZ are defined as the “common heritage of (hu)mankind” (CHM). In 1982, this legal status was confirmed in the United Nations Convention on the Law of the Sea (UNCLOS). This resulted in all resource exploration and extraction being managed by the International Seabed Authority (ISA).

The ISA is ‘mandated to develop, for the optimum collective benefit of all humankind, the mineral resources of the area, while taking the necessary measures to effectively protect the marine environment from the harmful effects of mining activities’ [1].
The ISA is currently working on the regulations to govern deepsea mining. These regulations will allow states and entities to obtain mining contracts to begin mining in international waters under the supervision of a sponsoring state. However, many states, academia (DOSI, IASS), non-governmental organisations (Pew, DSCC), intergovernmental organisations (IUCN), and others have expressed their concerns about the environmental impact that deepsea mining could cause. These concerns stem from the serious damage to ecosystems caused from mining terrestrial deposits throughout the world in the past. These damages can be minimised or even completely avoided due to the extensive research and regulations that are being put in place before mining begins. For this reason, it is extremely important that everyone involved is up to date and works together to ensure that there is minimal to no environmental impact, neither today nor for future generations.

Environmental issues

Over the past sixty years, there have been many ventures looking into the possibilities of deepsea mining and many have tried but failed to join this new growing industry. All the while there have been many activists arguing against deepsea mining and its harmful effects. It has even been described as the ‘new global gold rush’ in which ‘deepsea mining shares many features with past resource scrambles – including a general disregard for environmental and social impacts, and the marginalisation of indigenous peoples and their rights’.


Due to the vast area and effects of the proposed mining operation, the environmental effects must be properly researched and used as a basis for regulations and lawmaking. Many experiments that have been conducted studied the biological responses as a result of different types of nodule extraction and the various time scales of monitoring the restoration process. The most prominent methods of extraction included plowing or suction mechanisms, which disturb the seafloor and lead to vertical mixing and lateral migration of sediments. In addition, the change in physical/chemical conditions and effects on biomass were studied. However, more research is needed on the secondary effects of deepsea mining such as sediment redistribution, the effects of a full-scale supply chain including the distribution and processing of the metals.

To minimise sediment redistribution in the water column, all fullscale mining operations must fully enclose the systems. These systems include the lifting system that will transport the minerals, the harvesting tools, and ROVs (remotely operated vehicles). Contractors are also looking at screening the material at or near the seafloor to minimise the amount of unwanted material being transported to the vessel.

After the minerals are harvested, they are separated from the seawater, which is discharged back into the sea. This discharge will be below the euphotic (light) zone and/or near the seafloor to decrease environmental impact. Contractors are also looking into screens to minimise the effects of the returning sediment after discharge.

After extraction, the thousands of tonnes of mineral ore must be transported to shore for processing. Processing can produce excess waste, which will need to be disposed of properly to mitigate the effects on land. Although this process will not have as huge of an impact as the mining itself, it must be included in the regulations. Excluding the aforementioned concerns, the following paragraphs will discuss the general concerns from most parties.

Large area mining

Currently, the ISA has entered into fifteen-year contracts with 22 different contractors for exploration. Each contract gives a specific entity the right to a predetermined location and square footage. For polymetallic nodules, the exploration area is composed of 75,000 square kilometres (km2), for polymetallic sulfides, it consists of 10,000 km2, and for cobalt-rich ferromanganese crusts it consists of 3000 km2. This may seem like an extremely large area, however, the following points must be taken into consideration.

An area of 75,000 km2 with a minimum abundance of 5 kg/m2 (which is estimated as an example cutoff abundance for commercial viability) would contain a resource of 375 million tonnes (wet) or 280 million tonnes of (dry) nodules that can provide 187 years of mining at an annual mining rate of 1.5 million tonnes containing 2.8 million tonnes of nickel and copper each year (at one per cent concentration) and 0.28 million tonnes of cobalt (at 0.1 per cent) and 61 million tonnes of manganese (at 24 per cent) [3]. Meaning that if only a few mines were operational in various oceans, they would be able to supply the entire world's demand for copper, nickel, and cobalt. Although each contract is composed of 75,000 km2, it cannot be assumed that the entire area contains commercially viable nodules and that the entire area can be mined. Contractors have explained that only eighteen to fifty per cent can be mined. All contracts are at different stages and some are only beginning with research. With this in mind, there will probably only be around three to four mines operating once the regulations permit it.
Lastly, 75,000 km2 is around 0.044 per cent of the total area of the Pacific Ocean, 0.088 per cent of the Atlantic, and 0.10 per cent of the Indian ocean. As the mining will most likely be spread out between various oceans, its effects will be minimised as the effects will be localised.

Seafloor environments being destroyed

Another concern is that large amounts of the seafloor will be torn up at extremely high speeds not giving the environment enough time to balance and handle the negative effects. With conservative estimates, the mined area per year will only be around 300 km2 (one km2 per workday). However, this is a conservative estimate and may even be lower due to mining system efficiencies and/or higher nodule abundance.


Deepsea biota

From the experiments that have been conducted, it can be concluded that both sessile and mobile biota will be affected during the mining process. They will not only be affected during the mining process, but also during compaction, lifting, screening, and redistribution of sediment. Even if some organisms are destroyed, there will be large areas in the contract area that are not mined and left untouched. The ISA has also established Areas of Particular Environ-mental Interest (APEIs), which will not be impacted by mining. These areas will help the overall maintenance of the biota, maintaining the health and ecosystem around mined areas.


With an abundance of environmental problems, the companies and institutions will not catch a break when attempting to mine the bot-tom of the seafloor. Before they even start with mining, a full mining value chain must be set up: obtaining the correct licenses and permits, deposits, a mining vehicle, transport systems and mining vessels, processing and refining of the materials, and the correct logistics. Although many systems can be borrowed from deepwater oil drilling, there are still many more problems to overcome. Only re­cently has the technology in the oil drilling industry progressed enough to where oil wells have been drilled to around 3500 metres below the surface of the ocean. Whereas polymetallic nodules can only be found in depths of around 3000 to 6000 metres. Luckily, polymetallic sulfides and cobalt-rich ferromanganese crusts can be found in more shallow areas ranging from 800 to 4000 metres. Although ultra-deepwater drilling technology and systems from the oil industry can be adapted and used to pump the nodules to the surface, it is no easy task. This is one dilemma where companies have all struggled and all have taken their own approach. This combined with the task of powering these massive machines kilometres under the surface of the ocean has been a huge challenge. It is extra difficult because it has not been done before in any other industry, which has pushed companies to make new partnerships to overcome these newly presented challenges.

Not only are these metals kilometres under the ocean surface, they are also thousands of kilometres from the nearest landmass in the middle of the ocean.

To put this into perspective, most oil rigs or offshore wind farms can be reached with a short helicopter ride. To reach a deepsea mining ship, supply vessels would be needed to be placed in between the mining vessel and the shore so that the helicopter could refuel three to four times. Not only this, but bulk carriers would need to constantly be travelling between the shore and the mining vessel transporting the mined metals. These are only two pieces of the logistical puzzle to run such an operation, and it does not even include the effects that weather would have on the operation in the middle of the ocean.

Over the past decade, multiple pilot mining test programmes from various companies and consortia have been carried out throughout the world and the prospects for deepsea mining are improving. The pilot programmes have tested advanced mining vessels, remote crawlers, vertical transport systems and autonomous collector shuttles. Due to the wide range of subsystems, processes, and disciplines across the entire value chain, it is imperative that all systems are properly integrated and that companies work together on their specialisations. Although several small-scale tests have been completed in a direct approach, full-scale tests must be used to verify interdependencies and dynamic behaviours. In the end, international cooperation is necessary to share costs, capabilities, and competencies of deepsea mining.



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