O94 ON A METHOD OF EXTRACTING GOLD, SILVER, 
I bad also a small lot of copper pyrites from this Colony con- 
taining 24 per cent. of copper, and gold equal to 78 oz. 8 dwt., 
and silver 4 oz. 2 dwt. 10 grs. per ton; are pyrites con- 
taining when thoroughly roasted 11 ozs, 18 dwts. O grs. per ton; 
iron pyrites containing when roasted 5 ozs. 6 dwts. 3 grs. gold per 
on. 
As much attention has been given, by others more conversant 
than myself with mechanical manipulation, to the extraction of 
presence of heavy spar, &., or of tenacity from the presence of 
clay, seriously ‘reduce the yield of precious metals, consisting in 
their case principally of silver; and that nearly all the gold is Tost 
in the tailings, with about 15 oz. of mere reury per ton of ore treated. 
e loss of silver by amalgamation, he are with ores con- 
sidered suitable for that process, has been found to va r- 
many from 5 to 10 per cent. of the dcniaaaad quantity.* 
With the gue cri ores in Ban igT the ips is 12 per 
~ by barrel amalgamation, whilst with pore same ores by pan 
‘Att the Port Phi ip Works at Clun r - Latta reports that 
the average loss of gold by amalgamation of seven 
years was 6 O grs. per ton, the highest ie being 7 dwts. 
dwts. 
15 grs., the lowest 4 dwts. 8 grs., ths pyrites being free or nearly 
80 mort ees 
and le. 
Le treatment by fasion it is found at cosas ges in beta P 
dwts 
that after repeated fusion slags carry away 1 
‘ auriferous silver per ton; and in Lower Sesion by a similar 
_ loss is in the slags 1 oz. Po cages - ton, besides a 
does not exceed 65 per cent. of the assay, which is itself open nto 
losses. Acco to many Rage gas experiments, the lo 
arsenical pene to more than 50 per cent. The loss ae 
aren working on a large scale is less than in laboratory assays. 
att’s Dictionary of Chemistry, article 8 
+ S.A. Pillip Mining tnd Metallergy ot Gold and Silver. 
} Trans. R. Soc., Nsv S.W. 
Te Pe en te RE EME BSE NT oe Ret et Se ERED te ETSY 
