Amid global initiatives to phase out or limit the disposal of waste from extractive industries at sea, the mining industry should ensure safeguards are in place where marine tailings disposal is considered and where it offers a lower risk profile compared to terrestrial options.
Ludovic Rollin, Senior Environmental Engineer at SRK Consulting, says some companies that use marine tailings disposal could find it harder to access capital this decade due to Environmental, Social and Governance (ESG) concerns from investors.
'We are witnessing a growing backlash from non-government organisations, investors, communities, governments and the downstream supply chain towards marine tailings disposal methods,' says Rollin. 'The practice of marine tailings disposal is controversial among supply chain organisations. Responsible mining and sourcing assurance initiatives such as the World Gold Council are critical to the use of marine tailings disposal methods and customers might not appreciate the difference between, for example, submarine disposal and deep sea disposal methods.'
Marine tailings disposal involves transporting mine waste tailings from a mine processing plant to the sea through a submerged pipeline. Processed mud waste and rock waste slurries (tailings) are discharged directly into a marine environment through the pipeline.
As defined by the 2018 European Commission Best Available Techniques (BAT) Reference Document for the Management of Waste from Extractive Industries, Deep Sea Tailings Placement (DSTP) uses a submerged pipeline to release tailings material to a depth of 100 m or more, with waste designed to sink to greater depths and settle on the ocean floor. Submarine Tailing Disposal is the shallow-water version (less than 100 m) of this process. [1]
Marine tailings disposal is an alternative to land-based tailings disposal. Companies normally use marine tailings disposal methods when other options are not technically, economically, environmentally or socially viable. For example, a mine on a small island might face environmental and socio-economic constraints such as land pressure, protected biodiversity or cultural heritage sites that impact its ability to store extractive waste material on land, or there could be community opposition to land-based tailings disposal.
Donald Elder, Principal Consultant (Project Evaluation) at SRK, explains that 'Marine tailings disposal has potential for greater risks compared to land-based tailings disposal. You can’t get that mine waste back once you put it in the sea. And it’s much harder to monitor and control mine waste when it is hundreds of metres below the ocean’s surface.'
Elder expects marine tailings disposal to be phased out this decade. 'Some legacy mines will still use this method of tailings disposal, but there will be few new DSTP operations. Mining companies that plan to use DSTP should understand that there are substantial risks to securing external funding for companies that underestimate this issue.'
International experience
The mines that currently use DSTP are in Papua New Guinea (Ramu, Simberi and Lihir mines), Indonesia (Batu Hijau mine) and Türkey (Ҫayeli Bakir mine). These DSTP operations mostly involve unconfined discharges of mine waste into the deep ocean. DSTP has been used in Papua New Guinea (PNG) since the 1980s.
New DSTP operations have been proposed for the Woodlark and Wafi-Golpu projects in PNG. Wafi-Golpu is an advanced, world-class copper-gold porphyry deposit on PNG’s north coast.
Wafi-Golpu plans to use a pipeline to transport tailings to approximately 200 m below the ocean’s surface. In late 2020, the PNG Conservation and Environmental Protection Authority issued an Environment Permit for the project.
In 2021, the Morobe Provincial Government commenced legal action over the Environment Permit. After negotiation, a memorandum of understanding between the PNG Government and Wafi-Golpu Joint Venture was announced in April 2023.
Other DSTP projects in PNG have also been controversial among stakeholders. In 2020, a coalition of more than 5,000 villagers and a provincial government reportedly sued Ramu NiCo, who operates the Ramu Nickel Cobalt Project on PNG’s north coast.
The coalition demanded Ramu NiCo pay US$5.2 billion in restitution, stop disposing of its mine waste in the ocean, and remediate waters that are allegedly contaminated.[2] If successful, this would be the highest claim for environmental damage in PNG’s history.
In Norway, two of the country’s largest environmental organisations have brought legal charges against the Norwegian State for granting a permit to Nordic Mining to dispose of mine waste in the fjords (long, deep and narrow water bodies that reach inland). Norway is among the few remaining countries that allow mine waste disposal in fjords.
Nordic Mining has reportedly struggled to secure the required financing for the project and has lost some investment partners.[3] *
Future risks
DSTP operations could affect a company’s ability to access capital from international financiers and institutional investors in several ways.
The first is legal and permitting issues. Future changes in international treaties related to waste disposal at sea could increase the legal risks of DSTP and constrain its use. Regulatory uncertainty around DSTP could deter investors.
Future environmental concerns are another consideration. 'DSTP has unpredictable long-term impacts because little is known about the deep-sea ecosystem, including organisms on the sea floor and their role in oceanic food chains,' says Rollin. 'Companies might be required to seek independent scientific reviews of impact studies on marine life, which will open DSTP projects up to greater external scrutiny.'
Potential legal action and community claims against DSTP projects could also deter investors. High-profile legal cases and media campaigns against DSTP projects could diminish corporate reputation and affect a mining company’s social licence to operate.
'As legal, environmental and reputational risks from DSTP operations rise over this decade and next, so too could the cost of capital to finance these projects,' says Elder. 'Companies need to factor this in when determining whether to start a new DSTP operation, maintain an existing one or phase it out.'
Transparent approach
SRK’s Ludovic Rollin says some countries still grant environmental permits to use DSTP methods and notes that, where this is the case, mining companies should endeavour to be aware of good international industry practice principles and standards for marine tailings disposal. He notes the World Bank Group (through its International Finance Corporation) recommends that 'DSTP may be considered as an alternative only in the absence of an environmentally and socially sound land-based alternative and based on an independent scientific impact assessment.'
The World Gold Council’s Responsible Gold Mining Principles set out clear expectations for consumers, investors, and the downstream gold supply chain as to what constitutes responsible gold mining. Principle 8.2: 'We will not develop a new mine that would involve the use of riverine or shallow submarine tailings'. Although not specifically related to DSTP, the guidance emphasises the expert design, management and monitoring of tailings facilities.
The Initiative for Responsible Mining Assurance standard (IRMA, 2018), created by a coalition of non-government organisations, mining companies, and businesses purchasing minerals and metals for resale, states in section 4.1.8.1 'At the present time, mine sites using riverine, submarine and lake disposal of mine waste materials will not be certified by IRMA.' The June 2023 explanatory notes specify 'At the present time neither shallow nor deep sea tailings placement is allowed by IRMA.'
'The main message for mining companies from this and other guidance is that they should only use marine tailings disposal methods when it offers a lower risk profile compared to terrestrial options,” says Rollin. “If DSTP is the only option, it must be accompanied by a transparent approach, community consultation, and by expert design, monitoring and reporting, including independent reviews of the impacts of DSTP on waterways and the communities that rely on them.'
Breakout Box
Best practice: Eight key considerations for DSTP
1. Good international industry practice: Ensure tailings designs and management plans have been developed following recognised international good practices and standards and are signed off by an Engineer of Record.
2. Consultation: Develop and implement a stakeholder engagement plan and grievance mechanism within the wider community and activism groups to identify and address potential concerns regarding the use of the DSTP system.
3. Impact assessment: Develop an environmental and social impact assessment to demonstrate that tailings are not likely to have significant adverse effects on marine and coastal resources, or local communities.
4. Assess alternative strategies: Develop a prefeasibility study and environmental and social impact assessment including all tailings management alternatives (marine tailings disposal and alternative land-based facilities) and assess all alternatives based on comprehensive technical, economic, environmental and social criteria.
5. Management plan: Develop an environmental and social management plan to demonstrate sufficient mitigation and monitoring of the potential impacts and provision of the associated costs.
6. Closure: Develop a closure plan and a cost estimate for post-closure monitoring of the DSTP system towards relinquishment.
7. Independent review: Evaluate the need for an independent third-party review of the impact studies and management plans related to the implementation of the DSTP system, to be completed by a company known for its expertise in the marine environment.
8. Compliance: Secure the required permits for the project and ensure compliance with regulations.
References
[1] https://eippcb.jrc.ec.europa.eu/sites/default/files/inline-files/jrc109657_mwei_bref_-_for_pubsy_online.pdf
[2] https://news.mongabay.com/2020/05/locals-stage-latest-fight-against-png-mine-dumping-waste-into-sea/
[3] https://fjordsoksmalet.no/
* Since this article was published, Nordic Mining has won the court case, you can read about it here.
