tiippdund Auriferous Ores. 13 



The silver contents of our ores, when mixed, never amounted to 

 more thnn 5 ozs. per ton, so that silver was not specially worth 

 troubling over, though in the laboratory we could extract from 

 the tailings about 60 per cent, of their contents with a hypo- 

 sulphite solution, and 80 per cent., as well as a small quantity of 

 gold, with a cyanide solution. 



Repeated efforts were made to see if gold could not be recovered 

 by amalgamation from the roasted material, but 75 per cent, was 

 the utmost that could be obtained. The tailings from the 

 chlorination vats were also tried, but only 25 per cent, of their 

 gold would yield to amalgamation processes. It is exceedingly 

 diiiicult to amalgamate very fine gold, even when it is free. 



It is evident, though numberless modifications have been 

 suggested, many of which ha\e been carried out on Plattner's 

 original method, that for simplicity and applicability to almost 

 any ore it need never have been departed from. 



