COSTS AND STATISTICS. 



561 



"With such a mill, and using charcoal for burning cement, the cost 

 of manufacture .would be approximately as follows, allowing for power 

 only the proportion necessary for maintaining and operating the electric 

 plant provided": 



Per Barrel. 

 Labor and superintendence $0 . 70 



Raw materials 30 



Fuel for burning 99 



Power (maintenance and operation only) 05 



Repairs and sundries 05 



$2.00 

 This estimate is of interest in connection with the possible erection 



of plants at various points in Spanish America, where similar conditions 



may be encountered. 



The following general estimates have been prepared embodying 



the data presented on pages 554 to 559. It will be seen that they apply, 



except for the second and fifth cases, to very small plants, and that the 



totals are correspondingly high. 



TABLE 215. 

 ESTIMATES OF AVERAGE COST OF PORTLAND-CEMENT MANUFACTURE. 



Statistics of the American Portland-cement Industry. 



Statistics relative to the growth of the Portland-cement industry 

 in the United States will be found serviceable for many purposes, and 

 certain data on this point have been accordingly incorporated in the 

 present chapter. 



Total production and growth of the industry. The following table 

 has been prepared to illustrate the growth of the American Portland- 



