56 The ratio and Cazo Process. 







Grammes. 



Crushing with mule power, 



- 



- 17.360 



in arrastra, 



. 



57.860 



Washing on the plardlla, 



- 



- 17.360 



{ Labor 



34.720 





| Power - 



- 8.657 





i p ue i 

 Amalgamation. \ « ,. 



72.313 

 - 69.443 





| Mercury 



19.258 





[Distillation 



- 11.573 



215.964 



Cost in grammes per ton - • - - 308.544 



The very friable nature of the gangues has much to do with 

 the small cost of the concentration. The cost elsewhere in 



Grammes 



Cost of extraction and sorting, - - - 92.59 



Transportation, - - - - - 69.44 



Treatment, - - - - - - 231.47 



393.50 



This includes the cost of mercury, and shows a minimum for 

 the metallurgical treatment. The treatment of these ores gives 

 400 grammes in the cazo, which pays the cost, the profit being 

 in the treatment of the tails. 



An attempt was made in Chili* to treat rich sulphurous ores 

 with sulphate of copper and salt, but though it was a rapid process, 

 and the tails were poor, the enormous losses in mercury caused it 

 to be entirely abandoned. It was replaced by a method no longer 

 used, but which is interesting as showing how another grew out 

 of it. 



The ores upon which the i)rocess is used are the rich bromides, 

 chlorides and iodides of the upper part of the reins. The gan- 

 gue is oxide of iron, the carbonates of baryta and lime, and some 

 clay. They contain generally from 1300 to $400 of silver to the 

 ton. When such ores as these became rare, some other process 

 had to be used. This method caused the almost complete aban- 

 donment of the Cazo process proper; and it was not until the 

 ores became so very poor that it was no longer applicable, that it 



* Revue Universelle des Mines, Series 1, Vol. 31, p. 489. 



