The
total quantity of ore sold or treated and from which gold and silver
were produced decreased from 45,754,308 short tons in 1913 to
43,050,703 tons in 1914. The output continued, however, much greater
than that of 1912 and of preceding years and will probably materially
increase in 1915.
Utah,
Arizona, and Montana continued to lead in quantity of ore owing to
their vast output from copper mines, that from the first two States
being largely from low-grade disseminated ores and that from Montana
largely from the Butte vein deposits. Nevada ranked next in quantity of
ore, with output mainly from the Ely copper ores but also largely from
Tonopah, Goldfield, and other dry or siliceous ores. Colorado,
California, Idaho, and New Mexico came next, with tonnage for the first
two chiefly from dry and siliceous ores from many famous camps, for
Idaho mainly from the lead and lead-zinc ores of the Coeur d'Alene, and
for New Mexico chiefly from the copper ores of the disseminated type.
South Dakota, Michigan, and Alaska ranked next, the first and third
notable for the great outputs of siliceous ore from the Homestake and
Juneau regions, and Michigan for the great output of copper ores.
The
average gold and silver extraction values were high for the siliceous
ores of Nevada, Colorado, New Mexico, and a few other States and low
for the great ore bodies of California, South Dakota, and Alaska. They
were also high for the copper ores of Colorado and low for the ores of
most of the other important copper-producing States, notably so for
Utah, Nevada, Arizona, and New Mexico. The lead ores of Utah also
averaged more than double those of Idaho in precious metal value per
ton.
A
early 26 per cent of the output of ore considered as producing gold and
silver was dry or siliceous ore, against 23 per cent in 1913; and 64
per cent was copper ore, against 67 per cent in 1913; only about 5 per
cent was lead ore; and a little over 3 per cent was lead-zinc ore in
either year. The average precious-metal extraction value per ton of
siliceous ores decreased from $7.15 to $6.95 for the entire United
States, and of copper ore from $0.54 to $0.49 per ton. The average gold
and silver value of lead ores increased from $4.98 to $5.29 per ton,
however, and of lead-zinc ores from $2.48 to $2.90 per ten.
DISTKXBTTTION OF PRODUCTION OF GOLD IN 1914, BY SOURCES.
As
shown bv the following table, the great bulk of the domestic output of
gold is from dry or siliceous ores—normally gold quartz and gold-silver
quartzose ores—and from placers, nearly 92 per cent of the total
production of gold coming from these sources alone. The total
contribution cf gold derived from the great copper, lead, and zinc
mines of the country is therefore relatively small, notwithstanding
then- recent enormous development and tonnage. The changes in
relative-output from the various sources given in the table have been
unimportant in the last four years. It is interesting to note, however,
the gradual increase in placer production from 23.76 per cent in 1910
to 24.17 per cent in 1911, to 24.94 per cent in 1912 to 24.96 per cent
in 1913, and to 25.30 per cent in 1914; also corresponding decreases in
cutput from dry or siliceous ores from 68.91 per cent in 1910 to 68.52
per cent in 1911, to 67.29 per.cent in 1912, and to 66.45 per cent in
1913. There was a slight increase in
