The

SKYcost of
deep sea
miningJune 2023

HIGH

Trying to restore the damage caused bydeep sea mining would cost so muchthat neither companies nor governments
would pay for it
Financial institutions should therefore

not support deep sea mining

2

CONTENTS
Executive summary

4

Call to action

6

Introduction

7

What is deep sea mining?

8

Environmental impacts of deep sea mining

9

Deep sea mining is not aligned with global goals to protect
and restore nature

17

Deep sea ecosystem restoration post mining is an illusion

18

The astronomical cost of restoring deep sea ecosystems

21

An Environmental Compensation Fund to cover the restorationof deep sea ecosystems?

25

Conclusion

30

Appendix31

Disclaimer

33

References

34

deep sea

mining3

EXECUTIVE SUMMARY

L

and and sea use change is the leading driver of biodiversity loss globally.a
Deep sea mining has been proposed as an ‘environmentally friendly’
alternative to conventional land-based mining. However, research showsthat deep sea mining would cause significant permanent damage to deep sea
ecosystems and the broader oceans with which they interact.

Deep seas are biodiverse but still under-researched
While only a fraction of the deep sea has been studied, it contains many of the most pristine,
biodiverse and evolutionarily remarkable ecosystems on our planet. Deep sea mining risks
destroying undiscovered species and impacting the functioning of the global biosphere.

Deep sea mining risks environmental damage on a massive scale
Environmental damage is often measured in two dimensions (e.g., in km2). This report argues
that two more dimensions – volume and time – need to be considered to evaluate themagnitude of environmental damage, especially for marine ecosystems. Thinking in 3D isespecially important in the ocean, where the volume (in km3) affected by human impacts can becolossal. Time is critical for the recovery of ecosystems: the destruction of a habitat is evenworse if it takes millions of years to recover, as opposed to a few decades. Nature loss should
therefore be examined in 4D.

NODULES(deep sea)

25

Min.

CRITICAL MINERALS(terrestrial)

75

mn km3mn km3IMPACTED BIOSPHERE

Max.

10

1

mn km3mn km3Figure 1: Estimated range of the biosphere impacted by mining of nodules in international waters
and critical materials for the energy transition on land (min & max volume in million km3).
Source: Planet Tracker.34

See for instance UNEP (2022): 5 key drivers of the nature crisis or Jaureguiberry, P., et al. (2022). The direct drivers of recent
global anthropogenic biodiversity loss. Science advances, 8(45), eabm9982.
a4

Our analysis estimates that mining minerals critical for the energy transition on land impacts
biodiversity across 1–10 million km3. Deep sea mining would cause impacts on an even larger
scale. We estimate the total biosphere impacted by nodule mining in abyssal plains ininternational waters alone would be up to 25–75 million km3, more than the volumeof all freshwater in the world, including ice and snow. The risk of large-scale environmental
impacts from deep sea mining is driven by a combination of the enormous spatial scale of mining
activity and the spread of mining-related noise and sediment plumes.
On top of this, like crude oil, the polymetallic nodules at the centre of mining interests take tensof millions of years to form, but unlike crude oil, they are an essential habitat for life: over halfof the species living in the Pacific abyssal plains depend on nodules. Much of the habitat andbiodiversity loss caused by deep sea mining would therefore essentially be permanent.

Deep sea ecosystems are essentially unrestorable
The International Seabed Authority (ISA) and mining companies have suggested that deepsea ecosystem restoration could be used to mitigate these negative environmental impacts.
No details have been provided as to what restoration would look like in practice. Current
research indicates that the potential for successful passive and active post-mining deep sea
ecosystem restoration is extremely low, because of the long timescale and huge spatial impact ofenvironmental damage.

The cost of deep sea restoration would be astronomical
The use of artificial clay nodules is the only deep sea ecosystem restoration technique being
investigated in detail. We have estimated the total cost of artificial nodule-based deep sea
ecosystem restoration at USD 5.3–5.7 million per km2, which is more than the revenue atypical company would make from mining. The cost of restoration would be so high it would
be impossible for deep sea mining companies to pay for it and operate at a profit.
Table 1: Impact of restoration costs on deep sea mining profit generation.
Source: Planet Tracker, adapted from The Metals Company, 2021.
Item

Value

Annual area mined by a single company in 2030 (km2)

1,000% of nodules on the seabed that ends up collected on board carrier vessels

73%

Nodule abundance (wet kg/m2)

172030 estimated revenue (USD million)

4,3792030 estimated OpEx excluding restoration costs (USD million)

2,7212030 estimated EBIT margin38%

2030 estimated restoration costs (USD million)

5,2992030 estimated EBIT margin after restoration costs(83%)

However, this does not include the cost of monitoring restoration progress, which could increase
this figure significantly given the high cost of transport and remotely operated vehicles needed toaccess the seabed. In addition, the technology for artificial nodule deployment at scale does not
yet exist and if it did, the evidence so far indicates a low chance of successful restoration.

5

Neither public nor private money would cover that cost
An Environmental Compensation Fund has been proposed to fund ecosystem restoration as apart of the Mining Code being developed by the ISA. Our analysis found that this Fund cannot
be sufficiently capitalized to cover the estimated cost of restoration. Restoring only 30%
of potential deep sea mining concessions in international waters would likely cost more than theentire global defence budget.
There is also little evidence that the Fund and current draft restoration regulation has
considered best-practice from terrestrial mining restoration regulation, including costestimates. This could risk governments and tax payers footing the bill, as indicated by examples
from terrestrial mining.

The governance of deep sea restoration has been neglected
The current lack of transparency and accountability around the roles and responsibilities of
the ISA, sponsoring states and other parties poses a significant risk to the enforcement of postmining deep sea ecosystem restoration.
There are also limited opportunities for external scrutiny of deep sea mining impacts
and restoration, given the high costs of transport and remotely operated vehicles. For
terrestrial mining, civil society and academia have been important for holding companies andgovernments to account for managing environmental damage and ecosystem restoration.

CALL TO ACTION
Financial institutions should support a moratorium on deepsea mining
Deep sea mining is not aligned with global goals to protect and restore nature andcould expose financial institutions to significant policy, regulatory andreputational risks. Deep sea mining is likely to cause significant environmental damage
and this report has found that the likelihood of achieving deep sea ecosystem restoration
is low, while the cost is prohibitively high. Financial institutions should therefore
support a moratorium on deep sea mining.

6

INTRODUCTION

W

hile environmental issues are financially material for the vast majority
of companies,1 stock market prices are rarely directly impacted bynature-related events. Yet, when a video of a deep sea mining trial by
The Metals Company surfaced,2 showing the potential for significant negativeenvironmental impacts, the price of its shares (admittedly volatile) reacted
significantly and negatively.3 This highlights the importance that current andpotential investors attribute to environmental issues as they try to forecast thelikelihood of commercial deep sea mining becoming a reality.
Proponents of deep sea mining argue that it is less environmentally damaging than conventional
land-based mining. However, the broad scientific consensus asserts that deep sea mining would
cause significant permanent damage to deep sea ecosystems and the broader ocean ecosystems
with which they interact. Deep sea mining has been attracting significant and growing opposition,with companies, investors, national governments, scientists and civil society organizations callingfor a Moratorium on deep sea mining.4,5

Purpose, methodology and scope of this report
Considering the potential for environmental damage caused by deep sea mining, this report aims
to investigate the viability and costs of deep sea ecosystem restoration as a key driver of total
costs and risks for deep sea mining. It will also explore the options for funding and governing
post-mining deep sea ecosystem restoration and how these compare to learnings from terrestrial
mining.
This report focuses on the impact of mining polymetallic nodules in the Clarion-Clipperton Zone
(equatorial eastern Pacific), as this has received the most commercial interest to date and is themost likely area to be mined in international waters. Since nodules take millions of years to form,
removing them through mining would result in essentially permanent ecosystem destruction.
Current deep sea ecosystem restoration experiments indicate a very low chance of full recovery.
In addition, the analysis in this report indicates that the cost of deep sea ecosystem restoration
would be so expensive it would be impossible for mining companies to pay for it and operate at a
profit.
The information and recommendations in this report were developed using a bottom-up
approach, grounded in extensive literature review, expert interviews and primary analysis.
Planet Tracker aims to provide a practical working resource for financial institutions tounderstand and assess their exposure to the environmental risks associated with deep sea
mining. This report is aimed at financial institutions with potential exposure to deep sea mining
activities and those seeking to support the transition towards a sustainable blue economy. The
overall aim is to empower investors to better integrate nature and marine biodiversity into
capital allocation decisions.

7

WHAT IS DEEP SEA MINING?
WHY?

Deep sea mining refers to the extraction of metals and minerals from the deep seafloor, which
covers around 50% of the earth’s surface (360 million km2), representing 95% of the global
biosphere.6 There has been a surge of interest in deep sea mining in recent years, driven by theforecast rise in demand for metals for technology and the low-carbon transition and increasing
global metal prices.7

WHERE?
While the deep sea is technically considered to be below 200 m, most of the mineral deposits
currently under exploration are greater than 1,500 m below the sea’s surface.8 Major mineralreserves on the deep seabed have been known about for decades, but no commercial scale deepsea mining has taken place to date within national waters or international waters (the focus of thispaper), where rules are currently under negotiation by the International Seabed Authority (ISA)b.

WHAT?
The most important elements that could be mined from the seabed are: copper, cobalt, manganese,nickel, zinc, silver and gold.9 Three types of deep sea mineral deposits are of commercial interest:
polymetallic nodules, seafloor massive sulphides and cobalt-rich crusts – see Table 2. This reportfocuses on the impact of mining polymetallic nodules as they have received the most commercial
interest to date, particularly in the Clarion-Clipperton Zone (equatorial eastern Pacific).
Table 2: Commercially important deep sea mineral deposit types. Source: United Nations
Environment Programme Finance Initiative, 2022.
Deposit typeKey metals/minerals

Description

Polymetallic(Manganese)
Nodules

Manganese, nickel,
copper, cobalt,
molybdenum, rareearth metals, iron

Concentrations of iron and manganese hydroxides (5-10cm indiameter) occurring in the abyssal plains at depths of 2,000-6,500m.
Nodule fields of commercial interest have been found in parts of theClarion-Clipperton Zone (equatorial eastern Pacific), the Cook Islands(south west Pacific) and an area of the Central Indian Ocean Basin.

Seafloor Massive
Sulphides /Polymetallic
Sulphides

Copper, gold, zinc,lead, barium, silver,
sulphides

Metallic sulphide bodies are found at both active and dormanthydrothermal vents where hydrothermal fluid (at over >350°C) are/have been emitted. Deposits have been found in all the world’s
oceanic plate boundaries.

Cobalt-rich
Manganese, iron,(Ferromanganese) cobalt, copper,
Crustsnickel, platinum

Precipitation of manganese and iron from cold seawater forms
crusts up to 25cm thick on hard rock surfaces on seamount flanks,
ridges and plateaus at depths of 400–7,000m. Crusts of commercial
interest are found at depths of 800–2,500m on the flat tops of guyotsin the western Pacific.

HOW?
Currently polymetallic nodule mining is envisaged to use remotely operated vehicles10 to collect
nodules from the sea floor and pump them via a vertical riser pipe to a support vessel (boat)
before being transported to land for processing.6

The ISA is a small autonomous UN body, established in 1982 under the United Nations Convention on the Law of the Sea(UNCLOS).
b

8

ENVIRONMENTAL IMPACTS OF
DEEP SEA MINING

T

here are over 100 papers exploring the direct and indirect impacts of deepsea mining, most of which focus on the impact of nodule mining on the sea
floor, although studies on other deposits are underway.11 From this researchhas emerged the broad scientific consensus that deep sea mining vehicles andsediment plumes would cause significant damage to deep sea ecosystems andthe broader ocean ecosystems with which they interact.12
Yet the reality could be worse, since many of the effects of deep sea mining remain unstudied
and their scale is largely unknown.13 This section provides an overview of the key direct andindirect environmental impacts of deep sea mining – see Figure 2.

9Figure 2: Potential risks and impacts of mining polymetallic nodules on abyssal plains (not to scale).
Source: Fauna & Flora International 2021.

10

A biodiverse, under-researched, highly sensitive biome
The argument that deep sea mining is more ‘environmentally friendly’ often hinges on the false
assumption that the deep sea is largely devoid of life. While only a fraction of the deep sea has
been scientifically studied, it contains many of the most pristine, biodiverse14 and evolutionarily
remarkable ecosystems on our planet.15 Serious concerns have been raised about the potentialof deep sea mining to disturb undiscovered organisms.6 For instance, a recent study found thatfrom a total of 5,578 species recorded in the Clarion-Clipperton Zone (equatorial eastern Pacific),
92% were new to science.16
In addition, recently discovered deep sea species have generally been found to be highly
specialized, relatively slow growing and long-lived. This makes them particularly sensitive tophysical disturbance, including the impacts of deep sea mining.
Deep sea ecosystems are also known to provide the full range of ecosystem services and arehighly interconnected with broader ocean ecosystems – see Figure 3. However, the connections
between deep sea habitats and wider global functioning are poorly understood,17 raisingconcerns about the potential unknown broader impacts of deep sea mining.

Figure 3: Illustration of oceanic processes including primary productivity and the biological pump,and connectivity (not to scale). Source: Fauna & Flora International 2021.

11

Deep sea mining risks large-scale direct environmental impacts
The biggest direct impact of deep sea mining of nodules would be habitat and biodiversity loss,
as nodules are removed along with the organisms that grow on them, many of which, including
corals and sponges, cannot grow anywhere else18 – see Figure 4.

Figure 4: Sponge of the species Hyalonema obtusum with anemones attached to its stalk. The sponge is
attached by the stalk to a polymetallic nodule. Source: GEOMAR, ROV-Team.

These organisms have been identified as key structural species, supporting a huge range of faunaand playing a critical role in the food web19 – see Figure 5. Nodules take tens of millions ofyears to form, so the habitat and biodiversity loss caused by deep sea mining would
essentially be permanent.14 Over half of the species living in the Pacific abyssal plains dependon nodules.19

Figure 5: A deep sea cusk eel (Bassozetus nasus) in the nodule fields of the Clarion-Clipperton Zone.
Source: Diva Amon and Craig Smith/University of Hawai’i.

12

The sediment that makes up the deep sea floor would also be compacted, removed andredeposited by deep sea mining machinery. Sediments may take centuries to recover alongwith the microbes they host, which all life on the abyssal plain depends on,13 as the natural
sedimentation rate in the Clarion-Clipperton Zone is less than 1cm per thousand years.21
Deep sea mining has the potential to be particularly damaging because of the enormous spatial
scale of mining activity and its direct environmental impact. Over 1.5 million km2 of international
seabed has been set aside for deep sea mining exploration.22 This is about the size of Mongolia,
or more than the total area of sea trawled by bottom trawlers.23 In addition, many
countries have also awarded hundreds of thousands of km2 of seabed concessions for potential
mining. Norway, for instance, has granted 232,000 km2 of seabed concessions for mineral
exploration.24 Forecasts suggest that several hundred15 to a thousand25 km2 of seabed could be
disturbed each year by a single polymetallic nodule mining operation.
In comparison, terrestrial mining is currently estimated to cover 57,000–66,000 km2 of land,
which is about the size of Latvia or a thousand Manhattans.27 Therefore, even if only 5% of
deep sea concessions in international waters was mined (75,000km2), it would still belarger than the total area mined on land today.
Deep sea mining therefore risks directly causing habitat loss and damage to sensitive marine
ecosystems on an enormous scale, with a much larger land (or seabed) footprint than terrestrial
mining. Many of these impacts could be essentially permanent, particularly with the loss of
nodules which take millions of years to form.

Deep sea mining exploration22 hasover 1.5 million km2 of international
seabed set aside, which is about thesize of Mongolia

MONGOLIALATVIA

MANHATTAN
Terrestrial mining is currently
estimated to cover 57,000–66,000 km2 ofland, which is about the size of Latvia

Figure 6: Comparing the area of Terrestrial mining with Deep Sea mining.
Source: Tang & Werner (2023), Planet Tracker.

13Sediment plumes and noise amplify DSM impacts
The main indirect impacts of deep sea mining are associated with the sediment plumes andnoise created by mining activity which could have far-reaching impacts on ocean ecosystems. For
example, seabed communities could be smothered,28 toxic metals may be released,29 deep sea
fisheries could be contaminated30 and nutrients could be introduced into otherwise nutrient-poor
ecosystems.30 While these impacts are relatively under studied, existing research indicates they
are likely to be very difficult to control and contain due to the highly interconnected and dynamic
nature of the ocean.
Estimates for the total area of ocean that would be impacted by deep sea mining vary widely.
However, scientists agree that noise and sediment plumes from equipment disturbing theseabed and surface de-watering processes6,32 could have far-reaching effects on broader ocean
ecosystems.30 Sediment plumes alone could spread hundreds to thousands of km in the watercolumn,33 so the overall area affected by deep sea mining would be at least two to four times
larger15 than the area mined.
Research has also shown that in gentle weather conditions, the sound from a single nodule
mining operation could travel up to 500km.31
Within a 4–6 km radius, the sound would be above 120db, the threshold that denotes thepossibility of behavioural impacts on marine mammals. A total area of 5.5 million km2 would be
impacted by noise louder than ambient sound levels experienced in gentle weather conditions.31
We estimate the total area of biodiversity impacted by nodule mining in abyssal plains ininternational waters alone would be up to 12.4 million km2 – see Figure 7. This is assuming
impacts would extend within a 500 km radius of operations, accounting for sediment plumes andnoise generated by deep sea mining. This is an enormous area – if it was a country, it would
be the second largest, behind Russia and ahead of China.

Figure 7: Illustrative example of the area whose biodiversity would be impacted by the mining of nodules ininternational waters, assuming a 500km radius. Source: Planet Tracker map based on ISA data.

14

Importantly, given how sound and sediment plumes travel, biodiversity impacts for deep sea
mining have to be measured in km3 rather than km2.
Using the estimated area above, we calculate that the total biospherec potentially impacted
by nodule mining in international waters could be up to 25–75 million km3 – more than all the
freshwater in the world, including ice and snow (24 million km3).38 This assumes average verticaldistances (through the water column) of up to 2 to 6 km (nodules typically occur 4 to 6 km below
the ocean surface).19
In comparison, we estimate that the biosphere impacted by the mining of minerals critical for theenergy transition on land is unlikely to be larger than 1 to 10 million km3. This is based on existing
research estimating the area directly impacted at 25.4 million km2,36 and assuming terrestrial
mine impacts travel vertically between 55 m and 400m on average over the area impacted(underground and above ground, due to dust and other forms of air pollution) – see Figure 8.

NODULES(deep sea)

25

Min.

CRITICAL MINERALS(terrestrial)

75

mn km3mn km3IMPACTED BIOSPHERE

Max.

10

1

mn km3mn km3Figure 8: Estimated range of the biosphere impacted by mining of nodules in international waters
and critical materials for the energy transition on land (min & max volume in million km3).
Source: Planet Tracker.34cLife in the air, on land including soil, and in water.

15

Deep sea mining would barely reduce mining-related deforestation
Supporters of deep sea mining also often point to the damage caused by nickel mining in therainforests of Indonesia as an issue that could be mitigated by mining the deep sea. But would
deep sea mining reduce deforestation?
Mining is the fourth largest driver of deforestation, behind agriculture, infrastructure and urban
expansion, and mining-related deforestation has almost doubled in the 2010s compared tothe previous decade. However, 71% of the deforestation caused by mining is linked to justtwo commodities: gold and coal – see Figure 9. These two commodities were responsible for a
combined total of 6,877 km2 of forest loss between 2001 and 2019.

Figure 9: Breakdown of mining-related deforestation (in km2) over the 2001-2019 period by metal.37
Source: Planet Tracker, WWF.

In comparison, the mining of copper, cobalt, nickel and manganese (the metals present in deepsea nodules) led to 997 km2 of forest loss over the same period, or 12% of all mining-related
deforestation.37
Just one contractor in one area of international waters (The Metals Company) forecasts to mine
about 1,000 km2 of seabed a year in 2030,25 about twenty times the annual area of mining-related
deforestation by all mining companies globally for cobalt, copper, nickel and manganese (52 km2
a year).
Mining the seabed is therefore unlikely to significantly reduce terrestrial miningrelated deforestation, because only a fraction (if at all) of the metals mined from the seabedwould replace those mined on land.38 In addition, there is no indication that deep sea mining
would displace terrestrial mining; the sectors would instead become competitors in a larger
minerals market.39

16

DEEP SEA MINING IS NOT ALIGNED WITH
GLOBAL GOALS TO PROTECT AND
RESTORE NATURE

The environmental damage expected from deep sea mining detailed in theprevious section is not aligned with intergovernmental and national policy
agendas, which aim to halt biodiversity loss and promote nature restoration.

At the global level, UN Member States have committed to building synergies between existing
freshwater, marine and terrestrial ecosystem conservation and restoration commitments
and initiatives. This includes the UN Decade on Ecosystem Restoration, the UN Sustainable
Development Goals, and the Kunming-Montreal Global Biodiversity Framework, adopted byParties to the Convention on Biological Diversity in December 2022. A summary of relevant legal
frameworks can be found in Appendix 1: A summary of legal frameworks. Deep sea mining
even seems to contradict the ISA’s own mandate to ensure the ‘effective protection’ of
the marine environment and to ensure mining activities are carried out for the ‘benefit of (hu)mankind’.
More generally, Net Zero and ‘nature positive’ have become common expressions defining theambition of many organisations and jurisdictions to tackle the climate and biodiversity crisesd.
Deep sea mining companies have attempted to tap into this narrative with claims that deep sea
mining is more ’environmentally friendly’ than terrestrial mining. However, this does not matchthe mounting evidence that deep sea mining is likely to cause significant damage to oceanic
ecosystems. Even recent research funded by The Metals Company acknowledges the enormous
difficulty of comparing the worth of different ecosystems.40
This leaves companies and potential investors involved in deep sea mining exposed topotential policy and reputational risks, including greenwashinge.

Greenwashing

Net ZeroRISK
Naturepositive
GOALS
Google searches for Net Zero and ‘nature positive’ have respectively almost quadrupled and tripled between 2018 and 2023,
based on Google Trends.
de

For an overview of Greenwashing see Planet Tracker’s report: The Greenwashing Hydra

17

DEEP SEA ECOSYSTEM RESTORATIONPOST MINING IS AN ILLUSIONThe ISA and deep sea mining companies have indicated that deep sea
ecosystem restoration could provide a way of mitigating the significant
negative environmental impacts and associated risks detailed in theprevious sections.
The Society of Ecological Restoration defines ecological restoration as the process of “assisting
the recovery of ecosystems that have been degraded, damaged or destroyed”.41 The aim ofecosystem recovery is to create a self-supporting habitat similar to the ‘original’ habitat before
impact took place, or similar to a reference ecosystem. In comparison, ecosystem rehabilitation isless ambitious, aiming to replace structural or functional characteristics that have been damaged
and enhancing the ecological, social and economic value of the new ecosystem.42,43
Current research indicates that achieving successful deep sea habitat restoration (and evenrehabilitation) is extremely unlikely and our analysis shows the cost of proposed restoration
techniques would make deep sea mining financially unviable.
The narrative around deep sea restoration also ignores a key issue: the lack of detailed
understanding of deep sea ecosystems and their relationship with wider ocean ecosystems
indicates that no robust, precautionary approach exists to protect the ocean against the negative
impacts of deep sea mining.7 Ecosystem restoration should only be undertaken after everythinghas been done to avoid and minimize any negative impacts in the first place.14 This is indicatedby the mitigation hierarchy, which is usually used to manage environmental risks on land and incoastal areas – see Figure 10.

Net Position
Impact+ve

OffsetResidual
ImpactNet Impact

Biodiversity
ImpactAvoid

Residual
ImpactResidual
ImpactNo NetLoss

RestoreRestoreMinimise

Minimise

Minimise

Avoid

Avoid

Avoid

–ve

Figure 10: The biodiversity mitigation hierarchy.44 Source: UNEP FI.

18

The following section will detail the potential for deep sea ecosystem restoration and lessons
from terrestrial mining.

Deep sea ecosystem restoration potential: very limited
By removing nodules and compacting, removing and redepositing sediments deep sea mining
will cause habitat and biodiversity loss, some of which could last tens of millions of years, as
described in the previous sections. The potential for successful passive or active restoration ofdeep sea ecosystems damaged and destroyed by deep sea mining is therefore extremely low.13,20
In one experiment looking at passive restoration, the density and diversity of megafauna (greaterthan 1 cm) in an area disturbed to simulate the effect of a nodule collector vehicle were still
significantly lower than reference areas after 26 years.28
Even if these habitats were not destroyed or damaged by deep sea mining, ecosystem recovery
depends on organisms returning to a site, but this cannot happen if source populations aredestroyed by further mining, or are too far away because of the huge scale of mining activity.45
In addition, many organisms cannot travel across the vast and varied abyssal plain habitats andfor those which can, sediment plumes may also act as a physical barrier to recolonizing areas
affected by deep sea mining.

Replacing nodules with artificial nodules?
There is little research about the specific active restoration techniques that would be used after
abyssal plains were mined to extract nodules. One restoration technique explored in detail isexperiments with the use of artificial clay nodules, which began in 2021.20 These nodules are
made on land, transported on boats, then loaded onto remotely operated vehicles to the deep
seabed – a deep sea mining operation in reverse, where nodules are deposited rather thanmined, where the nodules will be studied for their suitability as a replacement for polymetallic
nodules. This restoration technique is the focus of the following sections exploring the potential
cost of deep sea restoration.

19

Learning from technical challenges in terrestrial minerehabilitation
The restoration of ecosystems impacted by deep sea mining appears to be partly inspired
restoration and rehabilitation for mining on land. The ecological restoration of degraded minesites should, in theory, facilitate a level of native ecosystem recovery, including the restoration of
biodiversity, as well as ecosystem structure, functioning and services.
However, many mine sites create such radical landscape change that rehabilitation is a more
likely outcome, resulting in a new or hybrid ecosystem with both native and non-native species.
Current best practice aims for progressive rehabilitation that starts when mines are in operation,
rehabilitating areas of the site no longer in use as new areas are opened up.
Despite growing demand, achieving successful mine restoration or rehabilitation faces major
technical challenges. These include: selecting, propagating and re-establishing species; controllinginvasive species and; monitoring the progress of rehabilitation.
In practice, terrestrial mine restoration and rehabilitation is often a process of trial-and-error, due
to the lack of systematic knowledge of how ecosystems function.46
Selecting the right species to include in degraded mine sites requires detailed information oneach species’ ecological niches. This is particularly important in the early stages of rehabilitation
where ‘nurse species’ are needed to attract pollinators as well as organisms that disperse
seeds and those that attract new species into the ecosystem. Considering the limited
understanding of deep sea species, ecosystem structure, functioning and services, it
is currently unlikely that deep sea ecosystems could be restored or even rehabilitatedeffectively.
Monitoring terrestrial mine rehabilitation is key to understanding whether ecosystems havebeen successfully restored, and is a legal requirement in many countries.47 Yet monitoring faces
significant challenges. Field-based monitoring, with rehabilitation staff physically visiting minesites, is still the most common approach for assessing ecosystem rehabilitation globally,48 but it
is labour intensive, time-consuming and expensive, especially with mines often located in remoteareas. As a result, monitoring is often insufficient or non-existent. Monitoring deep sea
ecosystem recovery is likely to face similar challenges, given the technical difficulty in accessing
deep sea environments, as well as the cost (discussed in the next section).
Remote sense monitoring, which has been used to monitor terrestrial mine restoration andrehabilitation since the 1970s, is increasingly providing opportunities to reduce the cost andeffort of monitoring. It also provides an opportunity for public scrutiny, from academic studies
to civil society groups tracking the environmental impact of mines remotely. This is important forholding mine operators to account in the context of poor monitoring. Similar levels of external
scrutiny for deep sea ecosystem restoration would be extremely limited given thecurrent limited access and high cost associated with transport and remotely operated vehicles.

20THE ASTRONOMICAL COST OF RESTORING
DEEP SEA ECOSYSTEMS

T

here are very few estimates of the costs of active deep sea ecosystem
restoration for polymetallic nodule fields, despite the significant commercial
interest they have garnered. Assuming deep sea restoration costs would be
similar to those of coastal ecosystems, Amon et al.44 conservatively estimate USD
50 billion would be required to restore just 10% of 500,000 km2 of abyssal seafloor
and “would probably still be inadequate to prevent substantial species extinctions”.
However, other research has pointed out that deep sea ecosystem restoration is likely to be
three to four times more expensive than for shallow water habitats,49 with coastal ecosystem
restoration costs ranging from USD 80 to 160 million per km2.50 The ships and remotely operated
vehicles required for deep sea ecosystem restoration are extremely expensive and are estimatedto account for 80% of restoration costs.51 In addition, the deeper the seabed, the more expensive
it is to access it – see Figure 11.

Figure 11: Price of various remotely operated vehicle models (manufacturers in brackets) in relation to the
maximum depth each model can access.52 Source: Planet Tracker, based on Teague, Allen and Scott (2017).

21

Costing the replacement of polymetallic nodules with artificial
clay nodules
The current cost of producing artificial clay nodules is estimated to be USD 0.10 per artificial
nodule.20 We have estimated the total cost of artificial nodule-based deep sea restoration at USD
5.3–5.7 million per km2, based on the following assumptions:
Table 3: Assumptions retained to estimate the total cost of replacing nodules with artificial nodules.
Source: Planet Tracker, based on sources listed below.
Item

Value

Unit

Source/comment

Average artificial nodule
weight180

grams perartificial nodule

Reference20
Assuming 1:1 replacement of existing nodules,
using The Metals Company’s NORI area as arepresentative example, based on The Metals
Company’s estimates of resource recovery, area
processed and moisture content53

Targeted spatial
distribution of artificial
nodules52

nodules/m2

Deployment cost of
artificial nodules

0.25

USD million/km2

Based on The Metals Company’s estimatedoffshore operating cost52

Average tonnage of dry
carriers used for thetransport of artificial
nodules

70,000tonnesNote: TMC’s TOML Technical Report assumed
that chartered vessels with 35,000 to 100,000
tonne deadweight capacity would be used totransport the dewatered nodules

Operating cost of a single
dry carrier vessel

9

USD million
per yearAssuming that the margins charged on shipping
costs would be minimal54

The cost of deploying the artificial nodules at scale is based on The Metals Company’s estimate
for the cost of nodule extraction. This assumes that the remotely operated vehicles and otherequipment used to extract the nodules could be operated in reverse: artificial nodules lowered
onto the seabed, rather than existing nodules being extracted from the sea floor. However, thistechnology does not currently exist.55 Alternatives including using remotely operated vehicles
to drop artificial nodules from a few meters above the seabed would mean the cost of therestoration would sky rocket to astronomical values.
The cost of monitoring restoration has not been included in these calculations because there
is currently no consensus on the exact resources and equipment needed and how frequently it
would occur. Currently, monitoring would almost certainly require the use of remotely operated
vehicles, significantly increasing the total cost of restoration, based on the evidence above.
Overall, using artificial nodules to restore abyssal plains impacted by deep sea mining islikely to cost between USD 5.3–5.7 million per km2, depending on whether artificial nodules
are deployed at the same time or after polymetallic nodule extraction. If artificial nodules are
deployed at the same time as polymetallic nodules are extracted, savings would be generated onremotely operated vehicles and transport costs.

22

Deep sea mining companies cannot afford the cost of restoration
If the cost of restoration had to be borne by mining companies, it would severely impact theirprofitability. Combining the forecasts and estimates from The Metals Company’s SEC filing,
we calculate that a company collecting nodules over 1,000 km2 of abyssal plain in 2030 could
potentially generate revenues of USD 4.379 billion with operational expenditures of at least USD
2.721 billion. This would mean a 38% operational margin, excluding other costs such as stockoptionsf. Per km2, the restoration cost we computed (USD 5.3–5.7 million) is higher than
the revenue made from the sale of nodules (USD 4.4 million), and about twice as high as
the cost of mining them (USD 2.7 million).
Adding the restoration costs as cash costs would turn that 38% margin into a large loss
equivalent to 83% of revenue – see Table 4. Considering the cost of restoration monitoring has
been excluded from our estimates, the loss could be significantly larger.
Table 4: Impact of restoration costs on deep sea mining profit generation.
Source: Planet Tracker, adapted from The Metals Company, 2021.
Item

Value

Comment/source

Area mined (km2)

1,000

In line with The Metals Company’s
2030 forecasts for its NORI area

% of nodules on the seabed that ends up collected on board
carrier vessels

73%

In line with The Metals Company’s‘resource recovery factor’Nodule abundance (wet kg/m2)

17

In line with The Metals Company’s
NORI Area D

Nodules moisture content (%)

24%

In line with The Metals Company’s
NORI Area

Average Nickel grade (%)

1.32%

Average Copper grade (%)

1.08%

Average Cobalt grade (%)

0.18%

Average Manganese grade (%)

29.41%

Nickel price (USD per tonne)

16,472

Copper price (USD per tonne)

6,872

Cobalt price (USD per tonne)

46,333The proportion of each mineralcontained in a dry nodule, in line withthe average in The Metals Company’s
NORI area

Prices assumed by The Metals
Company

Manganese price (USD per dry metric ton unit)

4.5

A unit is 10kg56

2030 estimated revenue (USD million)

4,379

Average offshore operating cost (USD million/km2)

0.25

The Metals Company estimate

Transport, processing, and SG&A costs (USD per dry tonne)

229

The Metals Company estimate

Royalties to ISA and states (USD per dry tonne)

33

The Metals Company estimate

2030 estimated OpEx excluding restoration costs (USD million)

2,7212030 estimated EBIT margin38%

2030 estimated restoration costs (USD million)

5,2992030 estimated EBIT margin after restoration costs(83%)

Assuming restoration occurs duringexploitation

We do not endorse this revenue forecast but use it as a basis to estimate the revenue generated by a company similar to TMC
based on all the assumptions it retained.
f23

Alternatively, the costs of restoration could be booked as liabilities upfront, as can be the case interrestrial mining. However, evidence from terrestrial mine restoration indicates that this would
create multiple issues, as discussed in the following sections.

Cost of terrestrial mining rehabilitation
There are a variety of different types of terrestrial mine closure estimates (including, minerehabilitation among other activities) used today to meet companies’ internal requirements andthose of investors, regulators and others. A detailed description of each type of closure costestimate is provided in the International Council for Mining & Metal’s (ICMM’s) Financial Concepts
for Mine Closure,57 a summary of which is available in Appendix 2: A summary of terrestrial mineclosure estimate types.

How well are terrestrial mine rehabilitation costs estimated?
Experts and regulators have highlighted that terrestrial mine rehabilitations costs are often
grossly underestimated. This is in part due to the myth that limited monitoring and maintenanceis required after mine closure, an assumption that is implied in most rehabilitation costcalculation tools used by industry and regulators.58,59 It appears that deep sea mining costestimates face a similar issue, with very little attention paid to the technicalities and cost ofmonitoring.
Evidence from the US and Australia, leading jurisdictions in the terrestrial mine rehabilitation
space, highlights that financial assurance is frequently significantly underestimated. For example,
in 2008, the US Government Accountability Office found that the financial assurances provided
for 52 hard rockg mining sites in operation at the time were around USD 61 million less than what
was required to fully cover reclamation costs.58
Regulators in some jurisdictions are beginning to recognise these risk and have begun reviews
and reforms in: progressive rehabilitation (while a site is still in operation), closure planning,risk assessment, residual risk calculation for risks that remain after mine closure and financial
provisioning for closure.57
Despite the wealth of information available on restoration cost estimates for terrestrial mining,the ISA and deep sea mining companies have provided very little to no detail on how deep sea
restoration costs would be calculated. Considering concerns of transparency and accountability,
there is also the question of whether the ISA would have the incentive or capacity to amend deepsea rehabilitation cost calculations or regulations if they prove ineffective.

gGold, silver, copper and other hard rock minerals.

24

AN ENVIRONMENTAL COMPENSATION FUND
TO COVER THE RESTORATION OF DEEP SEAECOSYSTEMS?

The cost of post-mining deep sea rehabilitation is likely to be prohibitively
expensive, as presented in our analysis in the previous section. Another key
question is: who would pay?

The current ‘Draft regulations on exploitation of mineral resources in the Area’, states that an
Environmental Compensation Fund would be created for deep sea ecosystems impacted bymining. The Environmental Compensation Fund would finance:60• Measures designed to prevent, limit or remediate any damage to the area;• The promotion of research into methods of marine mining engineering and practice to reduce
environmental damage in the area;• Education and training programmes;• Funding of research into best available techniques for the restoration and rehabilitation of thearea; and• The restoration and rehabilitation of the area when technically and economically feasible andsupported by best available scientific evidence.

The final point here indicates that if restoration and rehabilitation are not financially
feasible they will not be carried out. Based on our calculations, it is very unlikely that deepsea restorations will be financed by the ISA’s Environmental Compensation Fund.

The Environmental Compensation Fund is not fit for purpose
The Environmental Compensation Fund would be funded from a percentage of royalties andpenalties paid to the ISA by deep sea mining operators. Recent research highlights that thisfunding mix is not adequate since fines and donations are unstable sources of finance and thesystem of collecting royalties is subpar.61
In addition, our calculations show that the Fund cannot possibly be capitalised enough tofund the restoration and rehabilitation of the areas mined.
Even if 100% of the royalties collected by the ISA were used to capitalise the Fund (clearly an
unrealistic assumption), the cost of restoring the area damaged by deep sea mining would
be around 11 times bigger than the endowment of the fund. And this is solely for themining of nodules, not other forms of deep sea mining.
This is based on a royalty rate equal to around 10% of mining revenueh; exploitation hypotheses
in line with those assumed by The Metals Company and listed in Table 5 below; an average area
mined annually of 2,000 km2 and; an average cost of restoration of USD 5.65 million/km2. Other
research has suggested much lower royalty rates of 2%–6%.62

USD 33 per dry tonne (assumption used by The Metals Company), vs. estimated revenue extracted per nodule of USD 328 per
dry tonne.
h25

Table 5: Comparing the cost of restoration to the Environmental Compensation Fund capitalisation.
Source: Planet Tracker..
ISA royalties rate (USD per dry tonne)

33

Nodule abundance (wet kg / m2)

17

Resource recovery rate (%)

73%

Nodule moisture content (%)

24%

Km2 mined per year

2,000

Nodules extracted (million dry tonnes per year)

18.9

ISA royalties perceived (USD million)

622.5% of royalties channelled to fund capitalisation

80%

Fund capitalisation after one year (USD million)

498

Length of exploitation (years)

30

Average annual return of fund (%)

3.5%

Fund capitalisation at end of mine life (USD million)

32,134

Fund capitalisation (USD million per km2)

0.5

Cost of restoration (USD million per km2)

5.65

Total cost of restoration (USD million)

338,861

Total cost of restoration as % of fund capitalisation at end of mine life

1,055%

It is worth noting that assuming that only 2,000 km2 would be mined every year is very
conservative. It is equivalent to twice the area forecast to be mined by just one company (The
Metals Company) in 2030. Yet the associated cost of restoration over 30 years totals USD 339
billion. This is about five times more than the total forecast capital expenditures for the twenty
largest terrestrial mining companies globally.63
Even if research shows that more adequate payment mechanisms for deep sea mining are
possible,64 this report is the first to argue that no payment mechanism could fully fund the cost ofrestoration post deep sea mining.

ISA: a lack of transparency and conflicts of interest
More generally, concerns have been raised about the lack of transparency and independent
scrutiny in how the ISA operates and conflicts of interest between the ISA and the deep sea
mining companies it would regulate.14 The regulations are also being developed rapidly, largely
ignoring the precautionary principle (as already discussed) and with little public debate.65

26

Learning from terrestrial mine restoration regulations
The regulations being proposed for deep sea mining fall far short of current best-practiceregulations for terrestrial mining. On land, mine restoration regulations vary across the world,
but usually aim to return the mine site to a state that is non-polluting, safe, stable, with a selfsustaining ecosystem and can support an ‘agreed’ post-mining land use through progressive
rehabilitation.66
Today, Australia, Canada, Germany and the US state of Nevada are recognised as leading the way
in mine restoration and mine closure more generally.46
These jurisdictions have established stringent, wide-ranging and effective regulations combining
a command-and-control approach with economic incentives to encourage best-practice in themining sector. Current best practice emphasises:
Ensuring mine rehabilitation is integral to life-of-mine planning from project
inception, with a closure plan and cost estimate required as part of the mine
permitting process before development begins.
Developing well-planned post-mining landscape, encouraging progressive
restoration where possible.
Regularly reviewing and adjusting mine closure plans, cost estimates andfinancial assurance throughout the life of the mine, using the results of ongoingstudies, progressive restoration performance and stakeholder engagement. These
are adjusted annually in many jurisdictions and up to five years in others.
Setting specific, measurable, achievable, realistic and time-bound completion
criteria/targets to demonstrate rehabilitation has been achieved. These
contribute to companies’ relinquishing mine-related responsibilities.
Involving all stakeholders in mine closure planning, to build accountability andstewardship for post-mining landscapes.

There is little evidence to suggest that the current regulation around post-mining
deep sea ecosystem restoration has learnt from best practice in terrestrial mining.
This contradicts the ‘environmentally friendly deep sea mining narrative and provides anotherindication that environmental impacts are not being properly accounted for.

Is terrestrial mine restoration regulation implemented?
Despite significant improvements in regulation in recent decades, there is substantial evidence
from across the world that successful terrestrial mine restoration remains ‘an unrealised
aspiration’.67

27

Terrestrial mines hiding in care and maintenanceIn many cases, when mine operators fail to meet rehabilitation requirements, sites go intosome form of ‘care and maintenance’. Some sites close suddenly because external factors likecommodity price changes make a mine unprofitable, but some operators effectively use thisas a way of avoiding rehabilitation.65 This is particularly well documented in Australia65 wherean estimated 75% of mines close prematurely.68 However, there is often no clear definition or
management strategy for care and maintenance sites from regulators. In some jurisdictions, theresponsibility for enforcing site management might fall between the government departments
responsible for mines and environment. This means sites can remain in this state while
departments dispute responsibility.
There is a lack of clarity around the roles and responsibilities of the ISA, sponsoring states andother parties in supervising mining activities and enforcing regulations.14 This could mean little orno enforcement of any regulations that are developed around post-mining deep sea restoration,
considering the lessons above from terrestrial mining.

We could all pay for deep sea restoration through our tax bills
While the ISA recognises that deep sea mining would result in ecosystem destruction, themechanism proposed to fund the restoration of mined areas is inadequate and falls significantly
short of offering a satisfying guarantee that meaningful ecosystem restoration would happen.
Could this be solved by redistributing more deep sea mining revenue towards royalties, to better
capitalise the fund? No.
Even if 100% of the revenues generated by deep sea mining companies were allocated toecosystem restoration (clearly an unrealistic option), it would still not be enough to pay for
restoration using artificial nodules. The cost of restoring deep sea ecosystems after they
were mined is so high it is impossible for deep sea mining companies to pay for it andoperate at a profit.
Could governments step in, in a classic case of profits being privatised and ‘externalities’ picked
up by the public? They could, but their pockets would not be deep enough either. For instance,
restoring 30% of the area under a concession for potential deep sea mining (30% of c1.5
million km2) would cost more than the entire global defence budgeti - see Figure 12.

iPlanet Tracker calculations, compared to IISS (2023). Global defence spending – strategic vs economic drivers.

28

Figure 12: Benchmarking the cost of restoring the international seabed after it was mined(amounts in USD billion). Source: Planet Tracker.

In addition to the very low likelihood of successful restoration, the cost of restoring all theinternational deep seabed at risk of being mined is so high that it would require more thanhalf of the tax paid by individuals and companies globallyJ. This is similar to the total
investment needed between 2020 and 2050 to tackle the climate and nature crisis.69

Terrestrial mine rehabilitation: forced into government hands
Some terrestrial mine operators avoid paying for rehabilitation or restoration altogether bychoosing to forfeit the financial assurance to the state. However, as previously mentioned, thefinancial assurances required by regulators are not sufficient to cover the real cost of restoration,and these additional costs are left in the hands of the state.
It has been estimated that there are over 10,000 abandoned mines in Canada;70 over 50,000
abandoned mines in Australia71 (with an estimated rehabilitation cost of over AUD 1 billion);72
and over 161,000 abandoned mines in the US.58 In the US, The Government Accountability Office
found that from 1997 to 2008, four federal agenciesk spent at least USD 2.6 billion of taxpayers
money to reclaim abandoned hard rock mines on federal, state, private and Native American
lands.58
While governments may struggle to meet the cost of mine rehabilitation, in many jurisdictions
there is at least some accountability and monitoring of abandoned mine sites. Would the same
be true in the case of deep sea mining if operators fail to take care of rehabilitation costs? It is
unlikely.
In the unlikely event that governments would pay for the enormous costs of post-mining
deep sea ecosystem restoration, individuals and companies across the world could facesignificant tax rises.
To avoid derailing efforts to tackle the climate and biodiversity crises by spending enormoussums of money on the failed restoring deep sea ecosystems, there is an easy solution: notmining the seabed.
J

Planet Tracker calculations, based on World Bank datak

The Bureau for Land Management, the Forest Service, EPA and the Office of Surface Mining Reclamation and Enforcement29CONCLUSIONST

his report has found that deep sea mining of polymetallic nodules is likely tocause significant environmental damage on a huge scale and the likelihoodof achieving deep sea ecosystem restoration is minimal, while the cost is
prohibitively high.
Artificial clay nodules are being investigated for use in the restoration of the deep seabed
impacted by mining, with evidence so far indicating a low chance of meaningful ecosystem
restoration. We have estimated the total cost of artificial nodule-based deep sea restoration at
USD 5.3–5.7 million per km2 , more than the revenue a typical deep sea mining company would
make from mining each km2. However, this does not include the cost of monitoring restoration
progress, which could increase this figure significantly. In addition, the technology for artificial
nodule deployment does not yet exist.
It is not clear whether Environmental Compensation Fund put forward by the ISA would
fund deep sea ecosystem restoration. There is little evidence that the Fund and current draft
restoration regulation has considered best-practice from terrestrial mine restoration costestimation and regulations. Our analysis also indicates that if the Environmental Compensation
Fund did fund ecosystem restoration, it would not be sufficiently capitalized to cover the
astronomical costs. This could risk governments footing the bill, as indicated by examples fromterrestrial mining.
The current lack of transparency, accountability and clarity around the roles and responsibilitiesof the ISA, sponsoring states and other parties poses a significant governance risk to theenforcement of post-mining deep sea ecosystem restoration. Opportunities for external scrutinyof both impacts and restoration for deep sea mining would be extremely limited given thecurrent high costs associated with transport and remotely operated vehicles. All of this ignores
an important point: restoration should only be undertaken after everything has been done to
avoid and minimise negative impacts of deep sea mining, in line with the mitigation hierarchy.

Call to action
Deep sea mining is not aligned with global goals to protect and restore nature and could
expose financial institutions to significant policy, regulatory and reputational risks.
Financial institutions should therefore support a moratorium on deep sea mining.
Instead of investing in deep sea mining, financial institutions seeking exposure to a sustainable
blue economy could e.g., invest in: seafood traceabilityl, greater efficiency of marine protectedareasm, a blue recovery bond to reverse overfishingn, greater monitoring of fishing fleetso,
sustainable feeds for aquaculturep, regenerative aquacultureq, or greater recycling of shippingand fishing vesselsr.

lPlanet Tracker’s report: How to Trace USD 600 Billion.

Planet Tracker’s report: Rewarding Conservation Efficiency inMarine Protected Areas.
mnPlanet Tracker’s report: Can Blue Bonds Finance a Fish Recovery?

30

oPlanet Tracker’s report: Bonding with Observers.

p

Planet Tracker’s report: Bonds for Ponds.

q

Planet Tracker’s report: Avoiding Aquafailure.

r

Planet Tracker’s blog: Beached, not Stranded.

APPENDIX 1
A SUMMARY OF LEGAL FRAMEWORKS FOR BIODIVERSITY

B

elow is a summary of some key international and national legal frameworks
for the protection and restoration of biodiversity which relate to marine
ecosystems, including those that could be impacted by deep sea mining.

Legally-binding international frameworks• The Kunming-Montreal Global Biodiversity Framework, adopted by Parties to the CBD in

December 2022 commits the global community to restoring degraded ecosystems throughclear, measurable goals and targets to address the dangerous loss of biodiversity andsafeguarding ecosystem services and functionality, and lead the way to achieving the CBD 2050
Vision of “Living in Harmony with Nature”.

Nature restoration at the national and regional level• The Nature Restoration Law, introduced in June 2022 by the European Commission, would

require European Union member states to revive forests, wetlands and other sea- andlandscapes marred by human development. If passed, it will require Member States to develop
national plans to restore at least 20% of EU land and sea by 2030, and repair all ecosystems inneed of restoration by 2050.

• In France, the ‘France Nation Verte’ initiative details how the concept of ecological planning,
promoted by the government. One of its five core goals is the restoration of biodiversity.

• In China, Article XXXII of the 14th Five Year Plan for 2021-2025 states that the country will

promote the comprehensive management of ecologically degraded areas and the protection
and restoration of ecologically fragile areas.

31

APPENDIX 2
A SUMMARY OF TERRESTRIAL MINE CLOSURE ESTIMATE TYPES

A

summary of terrestrial mine closure estimates adapted from the ICMM’s
Financial Concepts for Mine Closure.73

Table 6: Summary of terrestrial mine closure estimates adapted from the ICMM’s Financial
Concepts for Mine Closure.71 Source: ICMM.
Type of mine closure
cost estimate

How it is used
• Costs that owners/operators expects to incur at the planned end of the mine’s life.

Life -of-Asset

Financial Liability/
Asset Retirement
Obligation• Used internally to estimate the expected total mine closure cost for asset valuation,budgeting and business planning.
• Includes cost of preparing for closure (research, trials and progressive reclamation),labour, decommissioning and demolition, post-closure monitoring andrelinquishment.
• Used to meet public financial reporting requirements to shareholders and stock
exchanges based on any legal obligation, liability or compliance as a minimum.
• Represents a net present value estimate of closure and reclamation costs of thecurrent disturbed area and mine infrastructure decommissions at the time ofreporting (normally annually).
• Used internally to evaluate business risk exposure to unforeseen changes in social,physical, political or economic conditions.

Sudden Closure

Regulatory Estimate/
Financial Assurance• Not usually used for regulatory purposes, but some jurisdictions may require aregulatory cost estimate based on assumed unplanned closure at a particular point
in time other than the end of mine life.
• Closure cost estimates required by regulators to establish a financial assurance
against sudden unplanned closure.
• Financial liability calculated for all phases of the mine lifecycle to exploration to fulloperation, not discounted by mine asset values.
• Based on a third-party, non-government contractor undertaking the work.

32

DISCLAIMER

As an initiative of Tracker Group Ltd., Planet
Tracker’s reports are impersonal and do not provide
individualised advice or recommendations for any
specific reader or portfolio. Tracker Group Ltd. is not an
investment adviser and makes no recommendations
regarding the advisability of investing in any particularcompany, investment fund or other vehicle. The
information contained in this research report does notconstitute an offer to sell securities or the solicitation of
an offer to buy, or recommendation for investment in,any securities within any jurisdiction. The information is
not intended as financial advice.
The information used to compile this report has beencollected from a number of sources in the publicdomain and from Tracker Group Ltd. licensors. While
Tracker Group Ltd. and its partners have obtained
information believed to be reliable, none of themshall be liable for any claims or losses of any naturein connection with information contained in thisdocument, including but not limited to, lost profits
or punitive or consequential damages. This research
report provides general information only. The
information and opinions constitute a judgment as at
the date indicated and are subject to change without
notice. The information may therefore not be accurate
or current. The information and opinions containedin this report have been compiled or arrived at fromsources believed to be reliable and in good faith, but
no representation or warranty, express or implied,
is made by Tracker Group Ltd. as to their accuracy,completeness or correctness and Tracker Group Ltd.
does also not warrant that the information is up to
date.

33

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ABOUT PLANET TRACKER
Planet Tracker is a non-profit financial think tank producing analytics and reports to aligncapital markets with planetary boundaries. Our mission is to create significant and irreversible
transformation of global financial activities by 2030. By informing, enabling and mobilising thetransformative power of capital markets we aim to deliver a financial system that is fully alignedwith a Net Zero, nature-positive economy. Planet Tracker proactively engages with financial
institutions to drive change in their investment strategies. We ensure they know exactly what risk
is built into their investments and identify opportunities from funding the systems transformations
we advocate.

ABOUT THE DEEP SIX PROJECTThis report is the first in a series of six, the ‘Deep Six Project’, focused on deep sea mining. The
goals of the Deep Six Project are to: 1) assess the potential environmental impact of deep sea
mining, including in relation to equivalent land-based mining and; 2) for investors to apply six
different learnings from the risks and opportunities of deep sea mining to other industries that
impact marine ecosystems, focusing on: climate change vs. nature considerations, resource-based
valuations vs. natural capital value, restoration potential, circularity, sovereign risk and stranded
assets risk.

ACKNOWLEDGEMENTS
Authors: Emma Amadi, Investment Analyst, Planet Tracker; François Mosnier, Head of Oceans
Programme, Planet Tracker.
Researchers: François Mosnier, Head of Oceans Programme, Planet Tracker; Emma Amadi,
Investment Analyst, Planet Tracker; Arianna Manili, Policy Officer, Planet Tracker.
Editor: Dominic Lyle
With thanks to: Bobbi-Jo Dobush, The Ocean Foundation; Ana Manero, Crawford School of
Public Policy; Gavin Mudd, RMIT University; Torsten Thiele, Global Ocean Trust; Adam Weiss,
ClientEarth; Andy Whitmore, Deep Sea Mining Campaign; and others that prefer to remain
anonymous.

WITH THANKS TO OUR FUNDER

Suggested citation: Amadi E., Mosnier F., The Sky High Cost of Deep Sea Mining: Planet Tracker (2023).

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For further information please contact:
Nicole Kozlowski, Head of Engagement, Planet Tracker
nicole@planet-tracker.org

www.planet-tracker.org #planet_tracker