Development of Aggregate Resources in Pacific Tropical Islands

Abstract

Small tropical Pacific islands suffer from a common problem of acquiring and maintaining an adequate supply of sand and aggregate for infrastructure develop ment, coastal protection, and beach maintenance. This is most critical in countries where atolls predominate, such as the Federated States of Micronesia, and the Republic of Marshall Islands, but presents difficulties in even the largest and most highly developed island communities such as Hawaii and American Samoa. Recent studies by the Marine Minerals Technology Center and others have indicated a Pacific-wide sea-level stillstand about 40,000 years ago which resulted in the formation of coastal terraces with significant sand beaches at depths of about 70 m. It is proposed that such deposits, in water depths of 50-100 m and seaward of the reefs, will serve as resources for sustainable development. Exploration should result in the discovery, throughout the region, of sand deposits containing tens to hundreds of millions of cubic yards of clean sand close to shore. These large deposits should be amenable to dredging by advanced technology at low unit cost. Stockpiles located appropriately throughout the region, integrated with a bulk transportation service, could supply projected needs at a cost which would be affordable to each community.