of
1906, the increase being traceable to Chaffee, Clear Creek, and Eagle
counties. Siliceous and dry ores yielded 91 per cent of the total gold
production. The tonnage of copper ore was small. The outlook for 1908
indicates a maintenance of the gold production at approximately the
same figures.
Colorado
produced 11,229,776 fine ounces of silver, a decrease of 987,054 fine
ounces. The principal reason for this lessened yield is to be found in
the closing of several mines toward the end of 1907. The smelting ores
of Lake County (Leadville) led, as usual, in the output of silver and
produced in 1907 4,154,913 ounces, an increase of about 250,000 ounces
over 1906. Pitkin County (Aspen) reported 1,719,446 ounces, a decrease
of over 400,000 ounces as compared with 1906. Mineral County (Creede)
produced 870,456 ounces, a decrease of about 250,000 ounces. The three
districts of Leadville, Aspen, and Creede yielded together 6,744,815
ounces. The San Juan country gave a total of 3,233,535 fine ounces, to
which San Miguel County (Telluride) contributed 1,438,299 ounces and
San Juan County (Silverton) 1,175,176 ounces. The Gilpin group of
counties reported 751,191 ounces, of which 518,364 came from Clear
Creek County. Ores classed as siliceous, which include a considerable
part of the Leadville ores, gave 7,409,999 ounces, or 66 per cent of
the output of the State. The lead ores proper yielded 2,357,981 ounces.
A further decrease in the production of silver is probable in 1908.
Idaho.—The
mines of Idaho yielded $1,255,911 in gold, an increase of $106,811. The
bulk of the gold came from the siliceous ores of Owyhee County (Silver
City) and amounted to $355,919. Boise County came next with a
production of $235,276, derived in large part from the placers of the
Idaho Basin. Custer County produced $175,869. The placers of the State
yielded $353,481, a slight increase over 1906. Siliceous ores
predominate in the gold-producing counties. Only a small quantity of
gold was obtained from copper ores. About $72,000 in gold were obtained
from dredging.
Of
silver 8,415,451 ounces were produced, a decrease of 603,384 ounces; of
this total, 7,266,862 ounces came from lead ores of the Cceur d'Alene
district, which is a small decrease as compared with 1906. Owyhee
County added 793,942 ounces from siliceous ores of Silver City, and
Blaine County (Wood River district) 170,367 ounces from lead ores.
Michigan.—The
mines of Michigan yielded 299,764 ounces of silver, an increase of
77,542 ounces as compared with the output of 1906. This silver was
produced by 10 companies operating copper mines and was chiefly derived
from electrolytic refining of Lake copper. A small part of the output
came, however, from '' pickings'' or metallic lumps saved in the "stamp
batteries. Amygdaloid ores contributed about 95 per cent of the
production, the remainder coming from the conglomerate ores. The yield
per ton of ore averaged 0.03 ounce of silver and from 1 to 2 per cent
of copper.
Missouri.—A
small quantity of silver is annually recovered from the lead of
southeastern Missouri. The silver content is only from 1 ounce to If
ounces per ton of lead. In 1907 25,692 ounces were obtained.
Montana.—The
gold production of Montana in 1907 amounted to $3,286,212, a decrease
of $1,182,802 from the output of 1906. This decrease was largely due to
the suspension of operations of many
