Placers.—The
output of silver from placers, mainly in Alaska and California, was
159,381 fine ounces in 1910, as against 152,040 ounces in 1909. The
recovery is by refining the placer gold.
Dry and siliceous ores.—The
output of silver from dry and siliceous ores was 23,125,042 fine ounces
in 1910, as against 19,826,890 ounces in 1909. The most notable gain
was in Nevada, from 9,456,840 ounces in 1909 to 11,763,012 ounces in
1910. Other increases in output of silver from this source were: In
Arizona, from 407,757 ounces to 440,126 ounces; in Colorado, from
5,716,373 to 6,117,719 ounces; in Montana, from 1,660,061 to 2,139,465
ounces; in Xew Mexico, from 323,962 to 708,762 ounces; in Utah, from
402,313 to 548,498 ounces; and in Washington, from 64,078 to 194,078
ounces. Output of silver from these ores decreased in California from
456,826 to 257,355-ounces, and in Idaho from 715,858 to 393,795 ounces.
The production from Texas showed little change. In order of production
of silver from this source the States ranked as follows: Nevada,
Colorado, Montana, New Mexico, Utah, Arizona, and Texas. With a few
notable exceptions, where there are mines producing true silver ores,
as in San Bernardino County, CaL, the dry or siliceous ores are
gold-silver or silver-gold ores (the latter notable at Tonopah, Nev.).
In Colorado the output is largely from Leadville, but also from San
Miguel County and from Creede in Mineral County. The largest output of
silver from the gold-silver siliceous ores is with the gold by
amalgamation and cyanidation, and the metals are separated in refining
the gold. Rich ores are usually smelted and the silver is then
recovered in the refining of the copper or lead bullion.
Copper ores.—The
production of silver from copper ores was 16,024,543 fine ounces in
1910, as against 18,300,705 ounces in 1909, corresponding to a reduced
output of copper in 1910, owing chiefly to curtailment at some of the
large mines. The silver production from copper ores is from
electrolytic refining of blister copper produced by smelting.
The copper ores are mainly sulphides, with a greater tonnage containing
chalcocite than chalcopyrite, and the great disseminated deposits of
Utah, Arizona, Nevada, and New Mexico, in the arid region of the Great
Basin, are of constantly increasing importance. These ores are mainly
concentrated before smelting. Oxidized copper ores of decreasing
relative importance, which are sought for as fluxing ores and commonly
smelted crude, still come from the Bisbee and the Tintic districts.
In
output of silver from copper ores Montana led with 9,153,590 ounces in
1910, as against 10,281,046 ounces in 1909. Utah followed with
2,036,909 ounces, against 2,500,717 ounces in 1909. Arizona produced
1,934,363 ounces, as against 1,830,998 ounces in 1909, and California
1,363,668 ounces in 1910, as against 1,539,665 in 1909. The decreases
in these States are marked, but the production in Colorado also
decreased from 1,058,894 to 436,358 ounces, and that in Idaho from
599,331 to 475,363 ounces. The output of Montana is mainly from Butte,
that of Utah from Tintic and Bingham, that of California from Shasta
County, and that of Arizona from Bisbee and Jerome. Of these the
Bingham camp alone represents the deposits of the disseminated type,
and the silver output from other copper ores is still chiefly from deep
lodes.
Lead ores.—Silver production from argentiferous lead ores was 15,028,076 fine ounces in 1910, as against 17,027,737 ounces in 1909.
