IV-318 



1966, with a value of approximately 33 million dollars. 



Yet, the mining of sand, gravel, and shell has a significant impact 

 on estuarlne conditions wherever it is practiced. Unlike petroleum, 

 the mining of these aggregates is not the spur for industrial and 

 population expansion. The reverse 1s true. Demand for coastal and 

 estuarine deposits of aggregates is the direct result of metropolitan 

 growth and related urban demands for cheap construction material in 

 the form of concrete and other building products. 



Since suitable construction aggregates are found nearly universally 

 on the Atlantic, Gulf, and Pacific coasts, and transportation of these 

 materials often makes up one-half or more of the costs to the consumer, 

 present and future growth of this industry in the coastal -estuary zone 

 will be dependent on increasing urban developments, and the availability 

 of competing deposits on the land surface. Thus, projections of growth 

 of coastal -estuarine extraction of aggregates are difficult due to the 

 fact that local demand and supply conditions are now and will continue 

 to be the major determining factor in decisions to exploit marine 

 aggregate resources. 



Sources of aggregate extracted from supplies in coastal rivers and 

 estuaries already provide the principal source of sand and gravel for 

 such metropolitan areas as New York, Philadelphia, Baltimore, 

 Washington, D.C., Norfolk, Mobile, and New Orleans. Oyster shell 1s 

 a major source of cement and associated lime requirements in Galveston 

 Bay, texas. Significant quantities are also mined in the San Francisco 



