Ch. 3— Minerals Supply, Demand, and Future Trends • 111 



production costs continue to rise and investment 

 in new mines is not justified, the shortfall between 

 domestic supply and domestic demand will have 

 to come from imports of lower-cost phosphate 

 rock. 98 



Sand and Gravel 

 Properties and Uses 



Sand and gravel is a nationally used commodity 

 which is an important element in many U.S. in- 

 dustries and is used in enormous quantities. Sand 

 and gravel can be used for industrial purposes such 

 as in foundary operations, in glass manufacturing, 

 as abrasives, and in infiltration beds of water treat- 

 ment facilities. 



Most sand and gravel, however, is used in con- 

 struction. Much of the aggregate is used in con- 

 crete for residential housing, commercial buildings, 

 bridges and dams, and in concrete or bituminous 

 mixes for highway construction. A large percent- 

 age of sand and gravel is also used without binders 

 as road bases, as road coverings, and in railroad 

 ballast. 



obtainable. Minable resources occur both onshore 

 and in coastal waters. Large offshore deposits have 

 been located in the Atlantic continental shelf and 

 offshore Alaska. ^^ The availability of construction 

 sand and gravel is controlled largely by land use 

 and/or environmental constraints. Local shortages 

 of sand and gravel are becoming common, espe- 

 cially near large metropolitan areas, and therefore 

 onshore resources may not meet future demand. 

 Crushed stone is being used often as a substitute, 

 despite its higher price. 



Domestic Production 



In 1986, about 837 million tons of construction 

 sand and gravel were produced in the United 

 States, industrial sand and gravel production ap- 

 proached 28.5 million tons' "'° and about 2.5 mil- 

 lion tons of construction and industrial sand and 

 gravel were exported."" The domestic industry is 

 made up of many producers ranging widely in size. 

 Most produce materials for the local market. The 

 western region led production and consumption of 

 sand and gravel, followed by the east north-central, 

 mountain, and southern regions. 



National Importance 



Generally, there is an abundance of sand and 

 gravel in the United States. Even though these ma- 

 terials are widely distributed, they are not univer- 

 sally available for consumptive use. Some areas are 

 devoid of sand and gravel or may be covered with 

 sufficient material to make surface mining imprac- 

 tical. In some areas, many sand and gravel sources 

 do not meet toughness, strength, durability, or 

 other physical property -equirements for certain 

 uses. Similarly, many sources may contain mineral 

 constituents that react adversely when used as con- 

 crete aggregate. Furthermore, even though an area 

 may be endowed with an abundance of sand and 

 gravel suitable for the intended purpose, existing 

 land uses, zoning, or regulations may preclude 

 commercial exploitation of the aggregate. 



Domestic Resources and Reserves 



Sand and gravel resources are so extensive that 

 resource estimates of total reserves are probably not 



Future Demand and Technological Trends 



Demand forecasts for U.S. construction sand and 

 gravel for 2000 range between a low of 650 mil- 

 lion tons and a high of 1.2 billion tons, with the 

 demand probably about 1 bUlion tons. Average an- 

 nual growth in demand is expected to be about 2.9 

 percent annually through 2000. '"^ Apparent con- 

 sumption in 1986 was about 836 million tons. 



Offshore resources may find future markets in 

 certain urban areas where demand might outpace 

 onshore supply because of scarcity or limited pro- 

 duction due to land use or environmental con- 



"Ibid. 



593. 



"J. Williams, "Sand and Gravel Deposits Within the United States 

 Exclusive Economic Zone: Resource Assessment and Uses," OTC 

 5197, Proceedings of the 18th Annual Offshore Technology Confer- 

 ence, Houston, Texas, May 5-8, 1986, p. 377. 



looy Xepordei, "Sand and Gravel," Mineral Commodity Sum- 

 maries— 1987 (Washington, DC: U.S. Bureau of Mines, 1985), pp. 

 136-137. 



'°'V. Tepordei and L. Davis, "Sand and Gravel," Minerals Year- 

 book— 1984 (Washington, DC: U.S. Bureau of Mines, 1985), p. 775. 



102Y Tepordei, "Sand and Gravel," Mineral Facts and Problems — 

 1985 Edition, Bulletin 675 (Washington, DC: U.S. Bureau of Mines, 

 1986), p. 695. 



