820 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1909. 
sulphide ore, so expensive in labor and fuel, were still practiced. We 
all, therefore, imagined in our shortsightedness that the day of doom 
for the copper interests of southern Arizona would date from the 
transition from oxidized to sulphide ore. Of the three districts, the 
only prosperous one during the succeeding fifteen years or so was the 
Warren, and for reasons which we now more clearly appreciate than 
we then did. The ores of the Copper Queen, or rather such of them 
as were then selected for treatment, were self-fluxing. They contained 
about 10 per cent of copper. The slags of that period, which we are 
now resmelting, contained about 2.5 per cent of copper. Assuming 
the slags to represent 65 per cent of the charge, about 16 per cent 
of the total copper content was being stored away in them. Less 
favorable conditions, however, existed at both Globe and Clifton. 
The ores of both these districts were extremely siliceous and the 
furnace charge of ore had to be diluted with from 40 to 50 per cent of 
limestone. The siliceous ores as treated were probably of about 12 
“per cent. The furnace charge was reduced by fluxing to between 7 
and 8 per cent of copper. The old slags—65 per cent of the total 
charge—yield at Glebe about 3.5 per cent and, therefore, must have 
carried from 30 to 32 per cent of the total copper fed into the fur- 
naces. We have retreated all the old slags of the Detroit Copper 
Company, at Morenci, near Clifton, and know that they carried on an 
average of 4.5 per cent of copper and must, therefore, have contained 
at least 40 per cent of the copper in the ore. At neither Clifton nor 
Globe was the dust collected, which probably represented a loss of 
another 5 per cent. Considering the high cost of fuel and labor, 
it is not to be wondered at that neither the Old Dominion, the 
Arizona Copper Company, nor the Detroit Copper Company, was 
financially successful for the first fifteen or sixteen years of their 
existence. It was not until all the richer carbonate ores had been 
wasted by being largely converted into slags that the companies 
recognized that their salvation depended upon securing sulphide 
ores; upon making metallic copper through the medium of matte, 
and throwing away less copper in their slags. So little, however, 
was this fact appreciated at first that we all envied the Arizona 
Copper Company, because it could turn the San Francisco River 
into its works and granulate and wash away this valuable refuse. 
And when the Old Dominion mine struck large volumes of water, 
the Old Dominion Company committed the same act of folly, wash- 
ing its 3.5 per cent slags into Pinal Creek. 
Had the companies realized the losses they were incurring and the 
only remedy applicable, they would have been obliged to lees both 
mines and furnaces; for except at the Copper Queca where sulphide 
ores were encountered within three or four years after the mine was 
opened and were considered a nuisance, heavy sulphides are rare. 
