292 



MINING INDUSTRY. 



In the patio the chemical loss is frequently very considerable; the 

 amounts of common salt and magistral employed are large, while, at the same 

 time, there is no reducing agent present to act upon the calomel formed, as is 

 the case in the pan. In the patio the loss is said to increase in proportion to 

 the richness of the ore in the sulphurets of silver, ovring to the fact that for 

 every atom of chloride of silver reduced by the mercury a corresponding atom 

 of the latter metal is consumed as sub-chloride. 



In the Washoe process the chemical loss v^^ould seem to be small in pro- 

 portion to the entire consumption. This is probably due to the beneficial ef- 

 fects of the iron, which combines with the chlorine of the calomel, setting the 

 quicksilver free. 



The more the metal is ground the more it must be cat up, and the greater 

 the difficulty in recovering it. Now, if the consumption of iron is assumed to 

 measure the grinding effect exerted by the pan, the relation between the loss 

 of mercury and that of iron should be, in a certain degree, proportional. 



The following table, compiled from the results of several mills, furnishes 

 some interesting details in regard to the loss of mercury : 



Part 1 shows that the loss of mercury is independent of the consump- 

 tion of chemical agents. 



Part 2 shows that the loss of mercury is, in some measure, dependent 

 upon the consumption of the iron of the pan. 



Tons of ore. 



I. 



2. 



Pounds per ton of ore. 



Pounds per ton of ore. 



Salt. 



Sulphate of 

 copper. 



Sulphuric 

 acid. 



Mercury. 



iron. 



Mercury. 



5.400 

 8,605 

 4,713 

 35, 000 

 7.523 



0.23 

 9.00 



0.33 

 1.74 



1.52 

 3.00 

 1.38 



0.18 

 0.31 



1-54 

 1.39 

 1-34 

 1-33 

 .79 



9.42 

 9-79 

 ,9-39 

 7.50 

 7.14 



1.54 

 1.38 

 1.38 

 1-33 

 1. 00 



i 



