158 



UNITED STATES MINERAL RESOURCES 



entirely self-sufficient with respect to stone requirements. 

 Volumewise, imports and exports are approximately equal, 

 but the value of imports, about $20 million in 1968, is ap- 

 promiately double that of exports. 



Use of dimension stone began when early man 

 gave up nomadic life, and it flourished when early 

 civilization built cities and temples. It is still an 

 important industry — 598 quarries produced $95 

 million worth of dimension stone in the United 

 States in 1970 (Division of Nonmetallic Minerals, 

 1972, p. 141) — but United States production was 

 highest in the 1920's, averaging about 4 million 

 short tons annually between 1925 and 1930 (Cur- 

 rier, 1960, p. 15). Following a period of small pro- 

 duction in the 1930's and early 1940's, production 

 increased after World War II from less than 1 mil- 

 lion short tons to 21/2 million short tons in 1955, but 

 has declined slightly since then. 



The crushed stone industry began in England in 

 about 1815 (Severinghaus, 1960, p. 285) and ex- 

 panded rapidly after the invention of the mechani- 

 cal rock crusher in 1858, especially during periods 

 of extensive railroad and highway building. In 

 1969, more than 4,500 quarries in the United States 

 produced 861 million short tons of crushed stone 

 (Wood and Carrales, 1970, p. 16), with a total 

 value of $11/3 billion. 



The recent, rapid growth of our domestic stone 

 industry is shown by table 34. These figures, from 



Table 34. — Production of stone, United States 



[AH figures are in millions] 



the U.S. Bureau of Mines Minerals Yearbooks, show 

 the tremendous increase in production of crushed 

 stone, chiefly caused by demands of expanded high- 

 way and other construction, and the gradual decline 

 of the dimension stone industry as use of concrete 

 and steel for structural materials increased. 



Imports in 1970 were valued at $35.7 million but 

 amounted to only about 2.5 percent of the total 

 value of stone consumed in the United States in 

 that year. About 84 percent of the imported stone 

 (by value) was dimension stone, chiefly marble from 

 Italy and Portugal and granite from Canada and 



Italy. Total value of stone exports was $5.6 million — 

 only 0.004 percent of the year's production (Drake, 

 1972). Prosperity of the stone industry does not 

 depend on either exports or imports. 



Demand is expected to increase, over the next 30 

 years, at an annual rate of 2.3-3.3 percent for di- 

 mension stone and 3.5-5.1 percent for crushed stone 

 (Cooper, 1970, p. 1229). 



DISTRIBUTION 



Stone was produced in 1970 in all States except 

 Delaware, and the total value of stone produced in 

 the United States reached a new record high of 

 $1.48 billion. More than 99 percent of the total 

 quantity, with 93.5 percent of the total value, was 

 crushed stone (Drake, 1972, p. 1). Stone was the 

 principal mineral, by value, produced in eight States 

 in 1970, was the second in 12 States, third in 10 

 States, and fourth in three (Daugherty and Fahr- 

 ney, 1972, p. 6). 



The eight most populous States produced 45 per- 

 cent of the total output of stone, which represented 

 40 percent of the total value in 1970. This reflects, 

 of course, the importance of the cost of shipping or 

 hauling stone from the quarry site to the place of 

 use. Inasmuch as the present heavily populated areas 

 will continue to be the principal areas of grovsd;h 

 and construction, they will continue to be the lead- 

 ing consumers of construction materials, and a 

 healthy and adequate stone industry must be main- 

 tained in and near all major population centers. 

 Nearly three-fourths of all crushed stone produced 

 in the United States in 1970 was shipped by truck 

 (Drake, 1972, p. 15). After a very few miles, the 

 cost of trucking can exceed the total of all other 

 production costs of crushed stone. 



Most kinds of rock are suitable for use as crushed 

 stone ; as a result no area in the United States is far 

 from an active or potential source of crushed stone. 

 Distribution of these sources of stone is shown in 

 figure 18. About 73 percent of the total output of 

 crushed stone, which represents 67 percent of the 

 total value, is limestone; traprock and granite are 

 the other principal varieties produced (table 35). 



Distribution of types used for dimension stone is 

 shown in figure 19. Granite is the leading variety 

 representing 37 percent of the total output and 46 

 percent of the total value; limestone and sandstone 

 are next in abundance (table 35). 



The principal competitor of and substitute for 

 crushed stone is another ubiquitous mineral com- 

 modity, sand and gravel. It is commonly used as a 

 substitute for stone in road construction and as 

 concrete aggregate. Usually, the availability and 



