454 



CEMENTS, LIMES, AND PLASTERS. 



means for final pulverization; the residues join those of the other screens 

 and with them are returned to the mill and subjected to further grind- 

 ing action of the balls until fine enough to pass the outside or finishing 



screen/ 



FIG. 100. Transverse section of Gates ball mill. (Allis-Chalmers Co.) 



TABLE 179. 

 SIZES, WEIGHTS, ETC., OF GATES BALL MILLS. 



NOTE. From 100 to 120 per cent additional power is required momentarily 

 in starting the above machines. When pulverizing to pass all through 20-mesh 

 from 30 to 40 per cent will pass a 100-mesh sieve. 



