Deep seabed mining

Article By:

Cruickshank, Michael J. Marine Minerals Technical Center, University of Hawaii, Honolulu, Hawaii.

Last reviewed:2013

DOI:https://doi.org/10.1036/1097-8542.YB130108

In the last half-century, our understanding of the global mineral resource base has changed drastically. The potential for commercial minerals per unit area in the oceans and seabed now appears to be similar to that on land. Almost three-fourths of the global mineral resources are in or under the sea and are virtually undeveloped. Half of the global seabed minerals are now controlled by coastal nations or small island states within their exclusive economic zones (EEZs), which extend 200 nautical miles (nmi) [370 km] from their shores. The other half are within the areas beyond national jurisdiction, known as the Area, and are controlled by the International Seabed Authority (ISA). The United Nations Convention of the Law of the Sea (UNCLOS), ratified in 1994, has resulted in the largest transfer of control of natural resources in history and in what is probably the most significant development in the history of the modern minerals industry—the exploration of the marine environment and the understanding of the potential for the development of marine minerals. In 1945, the Truman Proclamation on the outer continental shelf provided an initial impetus in the United States to go offshore for minerals other than oil and gas. Now every coastal nation has an EEZ and sovereign rights to its resources. The Area is administered by the ISA as a “common heritage of mankind,” and negotiations for mineral recovery from the oceans are made by the countries or entities involved. In the 1960s, the United States led developments in deep seabed mining, based largely on interest at that time in manganese nodules. Now, successful marine mining research and development is encouraged or subsidized by China, Japan, Canada, the United Kingdom, Australia, New Zealand, Papua New Guinea, Russia, Germany, South Africa, Fiji, the Cook Islands, and others. Extensive exploration and improvements in marine mining technology have resulted in the identification of deep seabed resources that were previously undiscovered or beyond economic recovery. These include, besides the ubiquitous manganese nodules, high-cobalt manganese crusts, metalliferous muds, marine phosphorites, seabed massive sulfides (SMS), methane hydrates, deep placer gold, diamonds, deep offshore sands, and precious corals. The greatest challenges to mining are in technology development and the mitigation of environmental issues. Processing of marine ores may be done on the seabed, onboard a surface platform, or on shore, depending on the particular deposit being mined. For the most part, the mining processes will be similar to those used for terrestrial deposits. Although all of the long-term effects of marine mineral resources recovery are not yet fully known, on the basis of current research it appears that the environmental effects of marine mining will, in general, be more benign than for equivalent recovery on land, and it appears highly likely that nondamaging recovery will be sustainable.

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