In This Article Expand or collapse the "in this article" section Marine Mining

  • Introduction
  • General Overview and Overarching Policy
  • Offshore Diamond Mining
  • Manganese and Phosphorite Nodules
  • Cobalt-Rich Crusts
  • Rare-Earth Element-Enriched Sediment

Environmental Science Marine Mining
Andrew David Thaler
  • LAST REVIEWED: 30 November 2015
  • LAST MODIFIED: 30 November 2015
  • DOI: 10.1093/obo/9780199363445-0047


In his underwater epic 20,000 Leagues Under the Sea (1869), Jules Verne speculated that the seafloor would one day yield untold mineral resources. Although he was correct, it would be nearly a century before the first marine mines became viable commercial prospects. This nascent industry has a short but complex history, with numerous stops and starts as the value of precious metals rises and falls. The first marine mines were established in the 1960s off the coast of Namibia, where fluvial diamond deposits could be found in relatively shallow (less than 400 meters) water. These diamond mines have remained in operation into the 21st century. Even with more than fifty years of continuous production, scientific evaluations of the environmental impact of offshore diamond mining on the surrounding marine environment are scarce. This phenomenon continues through the emergence of new marine mining industries, as technology and the promise of untapped mineral resources in the high seas progresses rapidly, with comprehensive environmental impact assessments conducted often in hindsight. Valuable marine mineral resources include manganese and phosphorite nodule deposits, cobalt-rich manganese crusts, polymetallic seafloor massive sulfides, and, most recently, rare-earth element-enriched sediment. The technologies needed to develop these mineral resources present a major barrier-to-entry for marine mining institutions and represent one of the largest bottlenecks to the successful establishment of a deep-sea mining industry. To date, and with the exception of offshore diamond mines, the marine mining ventures discussed in this article have yet to demonstrate commercial sustainability. As the marine mining industry matures and the inevitability of the first deep-sea mine draws closer, the scientific understanding of these ecosystems lags behind; conservation and policy initiatives are only beginning to be put into practice.

General Overview and Overarching Policy

Understanding the environmental consequences of mining in the ocean is a discipline still largely in its infancy. The deep sea provides essential ecosystem services that may or may not be threatened by the emerging deep-sea mining industry, described in Thurber, et al. 2014. The International Seabed Authority (ISA) has jurisdiction over seafloor mineral deposits that fall outside of states’ exclusive economic zones (EEZ) and is tasked with managing those resources “for the good of mankind,” summarized by Marvasti 1989. Currently, the ISA has adopted draft policies for the exploration and exploitation of manganese nodules (Clark, et al. 2013) cobalt-rich crusts (International Seabed Authority 2012) and seafloor massive sulfides (International Seabed Authority 2010), three of the potentially most profitable mineral resources. Although the ISA lacks jurisdiction within national EEZs, many nations have adopted policies informed by ISA regulations. Even as the marine mining industry makes significant progress in exploration and technological advancement, the regulations surrounding assessing and managing the environmental impacts of deep-sea mines, in particular, lag behind, according to Van Dover 2011, and include principles such as establishing baseline diversity measurements, assessing community connectivity, and identifying adequate and appropriate set-asides. Although the first era of deep-sea mining, beginning in the 1960s and ending in the mid-1980s, was considered an economic failure, documented by Glasby 2000, the future impacts of deep-sea mining, as outlined by Glover and Smith 2003, are uncertain.

  • Clark, A. L., J. C. Clark, and S. Pintz. 2013. Towards the development of a regulatory framework for polymetallic nodule exploitation in the area. ISA Technical Study 11. Kingston, Jamaica: International Seabed Authority.

    This report by the ISA lays out the proposed regulations for the exploitation of polymetallic nodules, including manganese and phosphorite nodule deposits in international waters.

  • Glasby, G. P. 2000. Lessons learned from deep-sea mining. Science 28:551–553.

    DOI: 10.1126/science.289.5479.551

    A short review of the early attempts at deep-sea mining drawing attention to the critical lessons learned in the early development of the industry.

  • Glover, A., and C. R. Smith. 2003. The deep-sea floor ecosystem: Current status and prospects of anthropogenic change by the year 2025. Environmental Conservation 30:219–241.

    DOI: 10.1017/S0376892903000225

    A forward-looking paper anticipating the potential anthropogenic impacts to the deep seafloor in the near future. This paper is a valuable introduction for students interested in human impacts on the seafloor, including the impacts of marine mining.

  • International Seabed Authority. 2010. Decision of the Assembly of the International Seabed Authority relating to the regulations on prospecting and exploration for polymetallic sulphides in the area. International Seabed Authority Assembly, 16th session. Kingston, Jamaica: International Seabed Authority.

    This report by the ISA lays out the proposed regulations for the exploitation of polymetallic seafloor massive sulphides deposits in international waters.

  • International Seabed Authority. 2012. Decision of the Assembly of the International Seabed Authority relating to the regulations on prospecting and exploration for cobalt-rich ferromanganese crusts in the area. International Seabed Authority Assembly, 18th session. Kingston, Jamaica: International Seabed Authority.

    This document lays out the requirements for exploitation of cobalt-rich ferromanganese crusts in international water.

  • Marvasti, A. 1989. Conceptual model for the management of international resources: The case of seabed minerals. Ocean Development & International Law 20:273–284.

    DOI: 10.1080/00908328909545893

    This policy paper provides an overview of the ISA’s role in the management and regulation of seabed mining activities in the high seas.

  • Thurber, A. R., A. K. Sweetman, B. E. Narayanaswamy, et al. 2014. Ecosystem function and series provided by the deep sea. Biogeosciences 11:3941–3963.

    DOI: 10.5194/bg-11-3941-2014

    This review covers the ecosystem services provided by the deep sea and investigates the potential consequences, both environmental and economic, to disrupting those ecosystem services.

  • Van Dover, C. L. 2011. Tighten regulations on deep-sea mining. Nature 470:31–33.

    DOI: 10.1038/470031a

    This position paper, by leading deep-sea ecologist Dr. Cindy Lee Van Dover, argues for increased regulations for deep-sea mining and was foundational in launching the current push toward enhanced awareness of the environmental consequences of deep-sea mining.

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