this class of ores, chiefly in San Miguel County (Telluride district), but most of the silver
is derived from dry ores containing lead and zinc in Leadville and
Creede, equivalent to Lake and Mineral County ores. These ores are, as
a rule, concentrated and smelted.
Copper ores.—Silver
to the amount of 15,762,947 tine ounces was obtained from copper ores
in 1905. This is a decrease of 5,360 ounces compared with the figures
for 1904, a somewhat surprising result in view of the considerable
expansion of the copper mining industry in the Western States. By far
the greatest quantity is derived from copper ores carrying only a few
ounces of silver, and the metal is really won as a by-product in the
electrolytic refineries. A little over two-thirds of the whole
quantity—to be exact, 10,624,594 ounces—is obtained from Butte, Mont.,
which State also shows an increase of about 400,000 ounces over last
year's figures for copper ores. Utah is next in rank, with 2,301,349
ounces, a decrease of 271,233 ounces from 1904. This decrease is really
technical rather than actual, for some of the ores classed as copper
ores in 1904 have this year been tabulated as copper-lead ores.
Arizona
is third in rank, with 1,480,732 ounces against 1,464,731 in 1904. The
principal source of argentiferous copper ores is the United Verde mine
at Jerome. At Bisbee a largely increased tonnage of copper ores was
mined, but they are extremely poor in silver.
Other
States which yielded over 100,000 ounces of silver from copper ores are
as follows: Idaho, California, and Michigan. California shows a notable
decrease, and Idaho took its place. Colorado produced only 55,388
ounces from ores which could be classed as copper ores.
Almost
all of the silver-bearing copper ores of the West are now sulphides.
Small quantities of oxidized ores are still contributed by Arizona and
New Mexico.
Lead ores.—Like
the gold, the silver from this source has been subdivided, according
to derivation, from lead ores proper or from lead-copper ores. The
total is about 21,500,000 ounces, which is a slight decrease from the
figures of 1904. In production of silver from lead ores Idaho leads
with over 7,000,000 ounces, an increase of nearly 700,000 ounces over
1904. The Coeur d'Alene mines in Shoshone County increased their yield
very considerably, while the Wood River districts in Blaine County show
a decrease. Colorado follows Idaho with a production of 3,883,827
ounces, representing a decrease of over 500,000 ounces compared with
1904. Pitkin (Aspen district), Lake (Leadville), San Juan, and Clear
Creek counties contain the principal contributing camps. Utah ranks
third and adds 3,104,375 ounces to the silver production from lead
ores. A comparison with the output of 1904 shows that the production of
silver from the combined lead and lead-copper ores was about 900,000
ounces less in 1905 than in 1904. The decreased output from the mines
of Summit and Wasatch counties (Park City district) was thus not fully
compensated by the increase from the Bingham, Tintic, and Frisco camps.
Montana
ranks fourth among the States producing silver from lead ores, and is
followed by Arizona and Nevada, but none of the three yields a million
ounces from this source.
Only
a very small amount of silver is derived from oxidized lead ores, which
are beginning to get very scarce, and which, moreover, ordinarily
contain but little silver.
Copper-lead ores.—Copper-lead
ores are marketed from Arizona, Idaho, and Montana. The similar ores
from Colorado contain, as a rule, too little copper to be properly
classed as copper-lead ores. In Utah copper-lead ores are especially
abundant, and a large quantity of silver, 5,290,122 ounces, was
derived in 1905 from the Park City, Tintic, Bingham, and San Francisco
districts, ranking in the order named. At Tintic, as well as at
Bingham, the larger part of the silver was derived from copper-lead
ores rather than from straight copper or lead ores.
