Case Study - South Taranaki Bight iron sand extraction

Iron sands are the largest known reserve of metalliferous ore in New Zealand. Iron sand is a general term for sand-sized grains of heavy iron-rich minerals, principally magnetite (Fe3O4), titanomagnetite (Fe2TiO3), and ilmenite (FeTiO3). 4576  New Zealand’s iron sands occur extensively in coastal dunes and on the adjacent continental shelf of the western North Island, and have been successfully mined onshore for over 35 years.

Over the last five years Trans Tasman Resources Limited (TTRL) has made two applications to the Environment Protection Authority (EPA) for a marine consents to mine iron ore off the South Taranaki Bight. The first application was declined in 2015. TTRL then revised its application which was successful in 2017. The 2017 decision is now under appeal to the High Court. 

There was a crucial change to the EEZ Act between the two TTRL applications due to Exclusive Economic Zone and Continental Shelf (Environmental Effects) Amendment Act 2013 (Environmental Effects Amendment Act) which excluded the application of adaptive management to marine discharge consents (s 87F4). These additions did not come into force until 31 October 2015, after the first TTRL decision and the decision on the Chatham Rock Phosphate application in 2013. The 2016 TTRL application could not separate the marine discharge consents from the other consents applied for as they were considered inherently connected, thus adaptive management was excluded from consideration entirely. 4577  However, whether or not the conditions as granted amount to a de-facto adaptive management regime is an issue in the appeal. 

Trans Tasman Resources Limited 2013 Application 

Trans-Tasman Resources Limited (TTR) holds a mining permit to undertake iron ore extraction in the South Taranaki Bight. In October 2013 TTR applied for marine consent under the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012 to undertake iron ore extraction in a 66 km2 area in the South Taranaki Bight. In June 2014 the Decision-Making Committee refused the marine consent application. The decision was appealed to the High Court but then withdrawn.

The project would have involved the excavation of up to 50 million tonnes (27 million cubic metres) per year of seabed material containing iron sand for processing on an offshore floating vessel. Approximately 10 per cent of the material would have been processed offshore into iron ore for export, with the remaining material returned to the seabed. 3550

Tree Fern Mt Taranaki (Credit: Raewyn Peart)

TTR prepared an environmental impact assessment, as well as more detailed technical reports, to support its application for marine consent. The Decision-Making Committee considered the effects on the environment as detailed in the table below.



Sediment Plume

The sediment plume was an important consideration as many effects of the proposal would result from it. A sediment plume model was provided and this was relied on to analyse other environmental effects. The Committee accepted that the plume model was fit for purpose and had an accuracy of -50 per cent to +100 per cent.

Primary Productivity

The sediment plume would reduce light penetration in the water column and therefore reduce primary production. Modelling predicted that there would be a three to four-fold reduction in light penetration at the mining site and a two-fold change in light penetration 10 kilometres east of the mining site. It predicted that this would result in a 10% reduction in total primary productivity in the South Taranaki Blight. The Committee concluded that there was considerable uncertainty as to the effects of changes in primary productivity on the wider ecosystem.

Benthic environment

The application area is a high-energy environment characterised by soft-sediment habitats subject to regular disturbance and colonised by fast-growing, opportunistic species. The area to be mined would be significantly disturbed with near total mortality of benthic fauna, with recovery taking approximately 10 years. The benthic environment outside the mining area would be subjected to sedimentation and reduced light levels as a result of the sediment plume.

Marine mammals

A number of dolphins, whales and seals could be present in the proposed project area, including a number with threat classifications (such as Maui’s dolphin, Southern/Antarctic blue whale and orca). Despite finding that the application area is unlikely to be primary habitat for Maui’s dolphin, the Committee determined that the threat status of the Maui’s dolphin meant that a very cautious approach was required. The Committee reached a similar conclusion in relation to blue whales. The activity had the potential to cause the following adverse effects on marine mammals: loss of food resources, displacement, noise effects, risk of collision and entanglement with vessels. The Committee considered that a comprehensive and longer-term baseline study of the marine mammals present in the South Taranaki Bight would have assisted it to understand the importance of the area to various species and what they use the area for. The absence of such information meant the Committee was uncertain as to the significance of the area affected to cetaceans. However, the consent conditions proposed by TTR were comprehensive and may have addressed those concerns if consent was granted.


The species richness of the reef, demersal and pelagic fish assemblages in the South Taranaki Bight is moderate on a national scale. The activity had the potential to cause the following adverse effects on fish: effects of suspended sediment and sedimentation, effect of heavy metals released into the water column, loss of benthic food sources, displacement of fish and loss of habitat, loss of spawning nurseries, noise, entrainment of fish in mining apparatus, and light spill from mining operations. The Committee accepted that the effects on fish were unlikely to be significant, provided no significant food web effects arose due to primary production changes.


No field surveys were undertaken to inform the report on seabirds. As a result, the Committee could not reach a conclusion as to the importance of the South Taranaki Bight for seabirds. The activity had the potential to cause the following adverse effects on seabirds: direct effects of vessel lighting and noise, effects of sediment on visual foragers and effects on the food web, including habitat loss and the loss of foraging areas. The Committee concluded that it lacked an understanding of how important the South Taranaki Bight is for seabirds and therefore the significance of the potential effects.


There is a risk that non-indigenous organisms could be introduced to New Zealand by ships transiting into New Zealand to support the proposed activities. The Committee accepted that these would be managed under the Biosecurity Act 1993.

Human health

The Committee considered four issues: air discharges from the combustion of heavy fuel oil in the engines on the vessels, contamination to seafood from the proposed operation, risk to other users of the South Taranaki Blight (e.g. recreational) and health and safety of workers. The Committee concluded that the effects on human health would have been manageable through consent conditions.

Physical environment

The Committee considered four issues: seabed bathymetry, waves and surf, coastal stability and the sediment budget and freshwater springs. It concluded that there would not be significant adverse effects on the physical environment. There was no evidence that changes to the seabed bathymetry would cause more than minor effects on waves, surf, coastal stability or the sediment budget.

Visual, natural features, natural landscapes and natural character

The mining activity, and the sediment plume created, had the potential to cause adverse visual effects. The Committee found that visual effects from the mining activity would be minor and visuals effects from the plume would be moderate. The impact on natural features and landscapes, outside the mining area itself, would be minor. The effects on natural character would be minor to moderate at the mining site and minor in coastal waters.


The Committee considered the potential for shipwrecks or other archaeological artefacts to be present in the proposed mining site and for these to be destroyed by the mining operations. It was satisfied that a proposed ‘Discovery Protocol for Shipwreck Finds’ would have appropriately addressed archaeological effects.

The Decision-Making Committee also considered effects on existing interests:

  • Iwi: Iwi were concerned that they had not received adequate information to allow them to make an informed response to the proposal. The Committee found that iwi’s existing interests would potentially be adversely affected in more than a minor way by the project. It acknowledged that the proposed consent conditions sought to involve iwi in a substantive way. However, iwi were not engaged in drafting those consent conditions and had not agreed to them.
  • Fishing: The Committee heard evidence regarding potential effects on commercial, recreational and customary fishing. It concluded that the “effects [on commercial and recreational fisheries] are at best uncertain”. It also concluded that there was “considerable uncertainty” with respect to customary fishing.
  • Recreation and tourism: The Committee found that it was unlikely that the proposal would harm New Zealand’s international reputation.
  • Origin Energy Resources:  The proposed mining area is adjacent (1.14 km) to the existing Kupe platform. The Committee found that Origin Energy Resources interests could be satisfactorily addressed, predominately through existing Crown Minerals Permit conditions.
  • Marine traffic: The proposed mining area is removed from regular marine traffic routes and therefore no conflict was considered likely.

The Committee determined that there was considerable uncertainty in the information provided to it as to both the nature of the environment and the way the mining operation might affect it. It also found information on how Māori existing interests would be addressed to be inadequate. 3564  As a result, under the legislation, the Committee was required to favour caution and environmental protection and to consider whether an adaptive management approach would allow the activity to be undertaken (section 61 of the EEZ Act).

Trans-Tasman Resources did not propose an adaptive management approach that would enable the activity “to commence on a small scale or for a short period so that its effects on the environment and existing interests can be monitored” for commercial reasons. Instead, the applicant proposed an approach which involved: 3565

  • Qualitative environmental performance objectives (specified in the consent conditions);
  • Pre-operational baseline monitoring;
  •  A process for developing quantitative “trigger indicators or values” which would inform compliance with environmental performance objectives;
  • Operational monitoring; and
  • Management of operations to achieve the identified environmental performance objectives.

The Decision-Making Committee assessed the approach against the following criteria:

  • The extent of the environmental risk;
  • The importance of the activity;
  • The degree of uncertainty; and
  • The extent to which an adaptive management approach will sufficiently diminish the risk and uncertainty.

The Trans-Tasman Resources’ adaptive management approach prescribed a process for the establishment of quantitative triggers based on qualitative Environmental Performance Objectives. This meant that the Environmental Performance Objectives were the ‘cornerstone pillars’ of the adaptive management approach. 3566  The Decision-Making Committee was concerned that the Environmental Performance Objectives were “very ‘general and ‘non-specific’”. 3567  They contained terms such as ‘no more than moderate’, ‘moderate impacts’ or ‘no more than moderate and temporary adverse effects’. The Committee was not confident that these could be reasonably translated into trigger values by a third party. The Decision-Making Committee was also concerned “that, without the option of a scale or staged implementation, the applicant has not provided any compelling adaptive management alternatives should the environmental objectives not be met”. 3568

The Decision-Making Committee concluded “Ultimately, the information we had to make our decision, while voluminous, was too uncertain and inadequate, and we did not have sufficient confidence in the adaptive management approach proposed to address that uncertainty to enable the activity to be undertaken. For all of these reasons, the application as presented to us does not meet the sustainable management purpose of the EEZ Act.”

Trans Tasman Resources Limited 2016 Application 

TTRL argued that since the 2013 application significant work had been done in regards to the baseline information issues that had been highlighted in the first application and the 2016 application was an entirely new application. Respondents however took a contrary view and argued that little work had been done in terms of gathering baseline data and that the only major change was the additional of new plume modelling including the consideration of flocculation which had significantly reduced the area affected by the application by nearly two thirds. The affected party interests and the key environmental effects were accepted by all as being largely the same for both the 2013 and 2016 applications. 

The Decision-Making Committee was split 2-2 and the chair was required to make the determining vote to grant the application. The decision is therefore the first seabed mining decision of the EPA to be drafted in two parts; with the decision of the majority and a decision of the minority found in part 2 as the “alternative view”. 

As in the first application, the key environment effect is the sediment plume and the resulting environmental effects that flow from it. Most of the effects of the plume will be felt within the Coastal Marine Area (CMA) to the South East of the mining site. A number of issues were raised by submitters early on in the hearing process specifically around the reliance placed on averages and operational assumptions when setting parameters for the plume modelling. This lead to a re-model of the plume considering what was described as a “worst case” plume model. 4578  The worst case model included setting new parameters for wave periods and conditions, percentage of fines, ocean current flows and shape of the pit. 4579  

The Majority decision found that most of the effects would be felt on alocalisedscale 4580  and temporary “albeit of consideration duration” 4581 ie: over the 35 year period of the consent. In summary the Majority found that: 

  • Impacts on a number of fish at particular locations within the CMA and the EEZ will range from no effect to severe but overall the application would not have any significant effects to fish at a population level; 4582
  • Impacts to kaimoana would be negligible both in respect of specific locations and across the wider South Taranaki Bight 4583 "filter feeders tolerate high turbidity. The sediment plume will dissipate before it reaches the coast and will be difficult to distinguish from background level”; 4584
  • There would be no effects from heavy metal accumulative or toxicity;
  • Thresholds on limits on the amount of noise 4585 that the operation generates and which is experienced in the marine environment will adequate protect marine mammals in the area; 4586 and
  • When the activity is complete the area will recover over varying periods. 4587

The Majority concluded that with the imposition of conditions, granting consent meets the purpose of the EEZ Act. 

Iwiorganisationsaffected by the proposed mining expressed universal opposition to the proposal. 4588

Concerns identified by Iwi included failure by the applicant to consult appropriately with the holders of mana whenua and that the application documentation did not include a cultural impact assessment prepared by Ngāti Ruanui who hold mana whenua. The Majority found that it was satisfied with the notification of Maori and Iwi groups.  The Majority considered that the interests of tangata whenua were restricted to the defined area of their rohe and not to the broader marine environment. While the Majority did acknowledge that there would be some impact on Kaitiakitanga, mauri and other cultural values, the Majority considered that the conditions would provide an opportunity for iwi to exercise kaitiakitangi through engaging in monitoring, and other scientific and operational aspects of the project.

 This is in stark contrast to the Minority decision. The Minority accepted the concerns raised by Tangata Whenua in regards to consultation as a “serious deficiency” and that the effects of the activity are more than an effect to kaimoana but also effect the broader environment and risks to marine life. As a result the Minority found that the Cultural Impact Report did not reflect the views of Mana Whenua. While this later point was accepted by the Majority as not being contrary to the Act, the Minority found that “the application does not adequately recognize the role of tangata whenua as kaitiaki and undermines their relationship with their rohe”. 4589 A large proportion of mana whenua rohe is within the area affected by the sediment plume on an ongoing basis over the 35 year period of the consent. This, the Minority found will “significant impact the ability of tangate whenua to exercise kaitiakitanga over their rohe and marine resources and will in their view adversely effect the mauri of the marine environment”. 4590

The Minority had a different interpretation leading to the findings reached in relation to the effects on the Patea Shoals (most notably to primary production), marine mammals and tangata whenua interests. 4591  The major differences in interpretation of the evidence was in relation to the uncertainty and the significant risks. 4592  The Minority stated that “even with more information and thus more certainty, localised adverse effects (as described by TTRL) on the coastal marine area (CMA) are, in our view, unacceptable and are contrary to New Zealand’s aspirations for protection of our marine environment”. 4593

In summary, the minority found:

  1. There are known adverse effects to the Patea Shoals (including primary productivity), marine mammals and Tangata Whenua which are significant under s 52;
  2. There was inadequate baseline information leading to uncertainty in effects therefore environmental precaution should be favoured under s 61(c);
  3. The inadequacy in baseline data lead compounding uncertainty in modelling.
  4. Even where that uncertainty could be resolved the effects to the environment and Tangata Whenua are so adverse as to be contrary to the purpose of the Act.
  5. Due to the uncertainty in the receiving environment it is impossible to draft adequate consent conditions. 



  2. Trans-Tasman Resource Marine Consent Decision (June 2014), at [138]

  3. Trans-Tasman Resource Marine Consent Decision (June 2014), at [793]

  4. Trans-Tasman Resource Marine Consent Decision (June 2014), at [816]

  5. Trans-Tasman Resource Marine Consent Decision (June 2014), at [820]

  6. Trans-Tasman Resource Marine Consent Decision (June 2014), at [850-851]

  7. Glasby, G.P.; Wright, I.C. (1990). Marine mineral potential in New Zealand’s Exclusive Economic Zone.

  8. Trans-Tasman Resource Marine Consent Decision (August 2017) page xvi at [41]. 

  9. Minute of the Decision Making Committee, 22 February 2017, Trans-Tasman Resource Marine Consent. Available at

  10. Minute of the Decision Making Committee, 22 February 2017, Trans-Tasman Resource Marine Consent at [2]. Available at

  11. Trans-Tasman Resource Marine Consent Decision (August 2017) page xiii at [15]. 

  12. Trans-Tasman Resource Marine Consent Decision (August 2017) page xiii at [25]. 

  13. Trans-Tasman Resource Marine Consent Decision (August 2017) page xiii at [15]. 

  14. Trans-Tasman Resource Marine Consent Decision (August 2017) page xiii at [16].

  15. Trans-Tasman Resource Marine Consent Decision (August 2017) page xv at [34]. 

  16. The threshold limits express the interim guidelines of the National Oceanic and Atmospheric Administration of the US Department of Commerce (NOAA)

  17. Trans-Tasman Resource Marine Consent Decision (August 2017) page xiii at [21]. 

  18. Trans-Tasman Resource Marine Consent Decision (August 2017) page xiii at [25]. 

  19. Trans-Tasman Resource Marine Consent Decision (August 2017) at page xv [35]. 

  20. Trans-Tasman Resource Marine Consent Decision (August 2017), page 229 at [8]. 

  21. Trans-Tasman Resource Marine Consent Decision (August 2017) page 229 at [9]. 

  22. Trans-Tasman Resource Marine Consent Decision (August 2017) page 228 at [2]. 

  23. Trans-Tasman Resource Marine Consent Decision (August 2017) at [30]. 

  24. Trans-Tasman Resource Marine Consent Decision (August 2017) at [30].

Last updated at 12:37PM on January 10, 2018