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REPORTS FROM THE SECTIONS. 257 
Another reef, the Copenhagen, contains a very considerable 
quantity of galena, a sample of the stone yielding 
Lead 13:47 
Silver 5oz. 16dwt. 48ers. per ton. 
Go QOoz. Odwt. 10grs. Pa 
The method adopted for the treatment of such of the ores as have 
been already washed is exceedingly crude, much of the silver 
being lost by the imperfection of the process. It seems probable 
indeed that most of the silver which has been hitherto obtained 
is that which is present in the ore in the free state, and that on 
further sinking on the reef when the water level is reached, and 
black unweathered ores only are obtained, the produce by the 
present method would be nil. . 
At present the stone after crushing is run over blankets, and 
the material saved on them is subjected to grinding with mercury 
in a Berdan pan, the tailings being run into pits, to be saved for 
subsequent treatment. The separation of the ore by the blankets, 
uf the slime had also been saved, wou ave been pretty 
Successful in the case of the first ores which I saw, but in recent 
specimens the silver is much more minutely disseminated through 
the quartz. 
If the contents of the stone going through the battery is com- 
pared with the products, it will be seen that great loss is ex- 
perienced ; thus, a sample of the crushed stuff gave 
Silver 83o0z. 12dwt. 19grs. per ton. 
Gold loz. Odwt. Ogrs. ,, 
Mr. Warden Graham reports that 5 or 6 tons of the stone is 
passed through the machine in twelve hours, and that about half- 
a-ton of this is saved on the blankets and yields 1000z. of silver. 
Now 5 tons contain 4180oz. of silver and 5oz. of gold, whilst the 
eaten of tailings from the Berdan would contain by my assay 
This grea 
the silver ores,—the finest slimes, which take many hours to settle 
in still water, invariably containing more silver than the original 
re. Phillips says of the Nevada ores that they yield 207 of 
slimes (not tailings), which from an ore containing 80oz. per ton 
contain 100oz. per ton of silver. I have myself found in. one 
the slimes to be much more enriched, and that, when the 
Mineral was carefully hand-crushed and dressed, but the quantity of 
the slimes produced was not more than 12% of the ore operated on. 
So 
