COPPER ORES.
The
mine production of silver from domestic copper ores in 1914 was
14,829,828 fine ounces, against 18,250,253 ounces in 1913 and
18,744,661 ounces in 1912. The decrease was largely due to curtailment
of output of copper at some of the largest properties in the latter
part of the year.
The
production of silver from copper ores is from the electrolytic refining
of Lake and blister copper produced by smelting. The copper ores are
mainly sulphides (except the Lake ores of Michigan, which are native
metal in amygdaloid and conglomerate matrix), and a greater tonnage
contains chalcocite than chalcopyrite or cupriferous pyrite. The great
disseminated copper deposits of Utah, Arizona, Nevada, and New Mexico
are of increasing importance, and the lode deposits of Butte, Mont.,
have long been famous. The silver tenor of the extensive Chino
disseminated deposits of the Santa Rita district, N. Mex., is notably
low, but similar deposits elsewhere add large quantities of silver.
Copper ores, especially sulphides, are mainly concentrated before
smelting. Oxidized copper ores, sought for as fluxing ore and commonly
smelted crude, still come from the Bisbee district of Arizona and the
Tintic district of Utah.
In
output of silver from copper ores Montana continued to lead with
8,015,694 ounces in 1914, against 10,311,809 ounces in 1913 and
10,655,055 ounces in 1912. Arizona followed with 2,604,371 ounces in
1914, against 2,885,115 ounces in 1913, and Utah ranked third with
1,726,230 ounces in 1914, against 2,314,348 ounces in 1913. California
produced 703,042 ounces in 1914, against 833,672 ounces in 1913. The
production of Montana is mainly form Butte, that of Arizona has been
chiefly from Bisbee and Jerome, that of Utah from Tintic and Bingham,
and that of California from Shasta County. Of these districts Bisbee
well represents the disseminated type; Bingham produces from both lode
and disseminated deposits; and the remainder produce silver chiefly
from copper ore mined from deep lodes.
LEAD ORES.
The
mine production of silver from argentiferous lead ores in 1914 was
19,302,081 fine ounces, against 18,629,246 ounces in 1913, a
considerable increase in 1914 over 1913 and a notable increase over
1912 and 1911. The output from Idaho increased from 7,806,445 ounces in
1913 to 8,697,580 ounces in 1914, but that of Utah decreased from
7,537,361 ounces to 7,350,213 ounces, and that of Colorado from
1,645,186 ounces to 1,532,943 ounces. The yield in Idaho is mainly from
the silver-lead ores of the Coeur d'Alene, that in Utah is chiefly from
the Park City and Tintic districts, and that in Colorado from Aspen and
Leadvifle. Most of the output is from the desilverization of lead
bullion from smelting of western ores and concentrates.
ZINC, LEAD-ZINC, AND MIXED ORES.
Argentiferous
zinc ores produced 145,264 ounces of silver in 1914, against 86,432
ounces in 1913, mainly as refinery by-products from the smelting of
zinc concentrates from Nevada, Montana, and Arizona.
