excavation (Smith and Gilbert 1975). Although mining of sand and gravel is 

 sometimes done by drag lines and front-end loaders, most excavation in the 

 study area is by hydraulic dredge. Nearly all of the sand and gravel is 

 processed by washing (Simpson and Smith 1968). 



Based on a maximum thickness of 3 m (10 ft) for the Citronelle Formation 

 and terrace deposits, and a minimum of 1.3 m (4 ft) for the alluvial 

 deposits, it has been estimated by Szabo et al . (1969) and Szabo and Clarke 

 (1969) that Mobile County contains over 218 million metric tons (240 million 

 short tons) of commercially available sand, while an additional 9.1 billion 

 metric tons (10 billion short tons) lie in Baldwin County. 



Beg (1980) gives a figure for total sand and gravel production in Alabama 

 of 8,219,180 metric tons (9,053,955 short tons) per year. The Atlas of 

 Alabama (Lineback 1973) states that the value of sand and gravel production 

 statewide was $9 million as of 1973. Figure 11 shows the variability in the 

 quantities of sand, gravel, and clay produced in Baldwin and Mobile Counties 

 from 1969 to 1975. Statewide production quantities and values for sand and 

 gravel from 1975 to 1979 are given in Table 29. Production quantities and 

 values from sand and gravel, sand and clay, and sand in Mobile and Baldwin 

 Counties in 1977 and 1979 are in Table 30. 



OO 



o 



o 







Q 



O 



CL. 

 Q- 



70 71 72 73 74 

 FISCAl YEAR 



r 



75 



Figure 11. Sand, gravel, and 

 clay production in Baldwin and 

 Mobile Counties, 1969-75 (for 

 October 1-September 30 fiscal 

 year)(Moser and Chermock 1978). 



122 



