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874 MINERAL RESOURCES, 1913—PART I.
ores,
as in parts of Colorado and Arizona; or smelting ores. Tailings both
from old dumps and from present milling are largely reworked by
concentration and subsequent cyanidation. The all-sliming cyanidation
method is also of increasing importance, and crushing is largely by
tube mills as well as by stamp and gyratory mills.
The
loss in tailings from gold mills is being constantly cut down and the
most serious present loss is in tailings from concentrating
g
iants. The
chlorination process is of decreasing relative importance melting is
mainly of concentrates and of siliceous and pyritic ores, which are
also valuable as fluxes. Exact figures of relative output by methods
will appear in detail by States in another table.
COPPER ORES.
The
production of gold from the electrolytic refining of blister copper
smelted from copper ores and concentrates sold or treated in 1913 was
$5,097,855, against $5,424,047 in 1912 and $5,450,079 in 1911. Increase
in gold output from these ores was made in 1913 in Arizona, California,
and Nevada and decrease in Montana and Utah. States producing over
$1,000,000 in gold from copper ores in 1913, as in 1912, were Utah and
Arizona, in order named, followed by the important contributors of less
than $1,000,000—Nevada, Montana, and California in 1913. The output of
gold from copper ores in the United States has increased from 5.63 per
cent of tho total gold yield from all sources in 1911 to 5.86 per cent
in 1912, and to 6.39 per cent in 1913.
LEAD ORES.
The
yield of gold from refining lead bullion produced from lead ores sold
or treated in 1913 was $1,527,246, against $1,348,087 in 1912 and
$1,201,606 in 1911. The Utah ores ranked first in output oi gold from
this source, followed by those of Colorado, as in 1912 and 1011. The
remainder of the gold yield from lead ores was chieily from Idaho,
Nevada, Arizona, Montana, and California, in order given. Increases
were noted for Utah, Colorado, and California in 1913, and decreases
from other States named.
LEAD-ZINC, ZINC, AND OTHER ORES.
Production
of gold from lead-zinc ores was $316,512 in 1913, against $258,177 in
1912, but the figures are not satisfactorily comparable for the reason
that ores from Montana classed as zinc ores in 1912 produced both lead
and zinc in 1913. The output from lead-zinc ores in 1913 was almost
wholly from Utah, Colorado, Montana, and' Arizona. From zinc ores the
gold production was $18,528 in 1913, against $100,898 in 1912, and was
chiefly in 1913 from Arizona.
From
copper-lead and copper-lead-zinc ores the gold output was $97,094 in
1913, against $47,538 in 1912, and was mainly from Nevada and Colorado.
DISTRIBUTION OP SILVER PRODUCTION OF 1913, BY SOURCES.
The
mine production of silver from dry or siliceous ores, copper ores, and
lead ores combined in 1913 was 91.15 per cent of the total
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