Hard Mineral Resources Around the US Continental Margin
Authors: Manheim Frank T. , Hess Harold D. 
Published: October 2008

The territorial waters surrounding the united States contain vast quantities of hard mineral resources. Some, such as sand and gravel in the New York Bight, Beaufort Sea, portions of southern California, and submerged lands near Hawaii are relatively well known and characterized by local need and immediate mining potential with available technology. Commoditie of interest to industry and having nearterm eCOnomic potential that might require new or innovative technology, inlcude phosphqrites such as those in the south eastern Atlantic margin, and manganese nodules on the Blake Plateau (which have potential for catalyst material, manganese, cobalt, nickel, and platinum). Commodities having significant potentia£, but which are poorly known and which may require innovative recovery technology, include chrome, gold, platinum, and tin placer deposits, with special emphasis on the continental margins of northern California, Oregon, Washington, and Alaska; rock salt and evaporite minerals in the Gulf of Mexico and Atlentic; titanium and other heavy minerals in the Atlantic continental margin, and calcium carbonate.

A. U.S. Department of the Interior moratorium on offshore leasing in federal waters has existed since 1968. Leasing and regulatory systems will be required to begin commercial mining or intensive exploration of the above resources.

Introduction

Conditions that bring National attention to offshore hard mineral resources include:increasing shortages of national or regional mineral suppliesthe expanding need for new sources of minerals in order to reduce pressure on existing supplies, and, in some cases, to lessen environmental impacts of land mining;the urgency of lessening U.S. dependence on foreign sources of minerals for industry, agriculture, transportation and defense;the economic and technological viability of offshore mineral recovery systems, as shown by mining activities of eight or more European coastal nations and several Asian nations;potential economic and other benefits, such as improvement of technological capability to be derived from commercial-scale offshore mining. A moratorium on offshore hard minerals.leasing by the U.s. Department of the Interior has been in effect since 1968. However, taking into arcount a variety of alternative uses of submerged lands, a Federal interagency task force study concluded that "sufficient interest and economic incentives exist to initiate commercial-scale hard-minerals mining in selected areas of the Outer Continental Shelf (OCS)," and that given appropriate federal policies to permit mineral development, "mining could be under~aken within acceptablelimits of environmental risk."

Resource Assessment

The Continentalzshelf of the United states has an area of 3 million km almost exactly one-third of the land of the Nation. Under the terms of the 1958 Law of the Sea Convention (Geneva), coastal nations have jurisdiction over their continental margin areas for mineral resource purposes to a depth of 200 m and as far beyond as superadjacent waters permit exploitation i.e. a seaward "technological exploitability" limit.