mines
of Shasta County produced 684,381 ounces in 1912, against 706,445
ounces in 1911 and 1,192,520 ounces in 1910. This falling off is due to
decreased copper smelting owing to litigation by agricultural
interests complaining of smelter fumes. Calaveras County also produced
97,819 ounces from copper ores in 1912, against 107,987 ounces in 1911.
Mono County produced 100,291 ounces and San Bernardino County 81,022
ounces of silver in 1912 from silver and silver-gold, dry or siliceous
ores. There were 12 silver mines and 25 silver-lead-zinc mines
producing argentiferous ores in California in 1912, mainly in Inyo,
Kern, Mono, and San Bernardino counties.
COLORADO.
Gold.—The
gold production of Colorado in 1912 was $18,588,562, against
$19,001,975 in 1911, a decrease of $413,413 from the production of
1911, of $1,918,496 from that of 1910, and of $3,400,774 from that of
1909.
The
Cripple Creek district (Teller County) produced $11,008,362 in gold in
1912 (an increase of $445,709), or 59 per cent of the gold output from
all sources, or nearly 61 per cent of that from all Colorado deep
mines. The San Juan region (Dolores, La Plata, Ouray, San Juan, and San
Miguel counties) produced $4,119,191 in 1912, against $5,035,610 in
1911, $5,822,422 in 1910, and $6,170,201 in 1909. Ouray County alone
produced $903,368 in gold less than in 1911, this decrease being nearly
equal to the decrease for the entire region.
Of
the total material treated, dry or siliceous ores yielded $17,391,129
in gold in 1912, or nearly 94 per cent of all the gold output from the
State, the value and relative yield being about the same in 1911. Lead
ores and placers each supplied about 2 per cent, and the remainder of
the output was from copper, copper-lead, and zinc and lead-zinc ores,
in three nearly equal parts. The production of placer gold was
$423,885, against $319,759 in 1911, the greater part of the output
being from Summit County where three dredges and eight other placers
were in operation in 1912.
Silver.—The
silver production of Colorado in 1912 was 8,212,070 fine ounces,
against 7,330,168 ounces in 1911, 8,509,598 ounces in 1910, and
8,902,633 ounces in 1909. Lake County (chiefly the Leadville district)
production showed a decrease of 6,899 ounces in 1912, following
decreases of 314,719 ounces in 1911 and of 101,627 ounces in 1910; but
the county produced 37 per cent of the State yield in 1912, against 41
per cent in 1911, 39 per cent in 1910, and 38 per cent in 1909.
Decreases of note were also made in La Plata and Clear Creek counties,
but notable increases were recorded from San Juan, Mineral, and San
Miguel counties.
Dry
or siliceous ores in Colorado yielded 5,397,439 ounces of silver in
1912; lead ores, 1,470,930 ounces; lead-zinc ores, 594,427 ounces;
copper-lead ores, 389,449 ounces; copper ores, 224,327 ounces; and zinc
ores, 130,392 ounces.
MARYLAND AND PENNSYLVANIA.
Silver.—In
Maryland a small production of copper concentrates was made from the
New London mine in 1911 and 1912, resulting in a nominal output of
silver from refining the copper produced. In Pennsylvania the Cornwall
iron mines produce a small quantity of
