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MINERAL RESOURCES.
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Source
of gold in 1911 in States and Territories, as reported from the mines
to the United States Geological Survey, by kinds of ore and by States,
in fine ounces—Continued.
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RECOVERIES BY METHODS OF TREATMENT.
In
another table data are given showing relative recoveries of deep mine
gold by methods of treatment in mills and by smelting. For 1911 the
placers, whose product is largely mechanical, although in part by
amalgamation, produced 24.2 per cent of the total gold, as shown above;
the gold mills produced (all from siliceous ores) 54.2 per cent of the
total output—23.9 per cent by amalgamation, 26.5 per cent by
cyanidation, and 3.8 per cent by chlorination; and the smelters
produced the remaining 22 per cent—14.7 per cent from dry or siliceous
ores and 7.3 per cent from all other ores combined. These figures can
not be compared with those for previous years, for detailed data of
this kind were obtained for the first time, so far as known, for 1911.
It will probably be found from future comparisons that relative
recoveries from placers and by chlorination will in general decrease.
PLACERS.
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The
total value of the gold placer production was $23,415,168 in 1911,
against $22,515,889 in 1910. These figures represent 24.17 per cent of
the total domestic gold output for 1911 and 23.76 per cent of that for
1910. The place/production of Alaska was $12,540,000 against $11,984,806 in 1910, and that of California was $8,986,527 against $8,888,795 in 1910.
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