Environmental Science Marine Mining
Andrew David Thaler
  • 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.

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