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GOLD AND SILVER.
749
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and
426,019 ounces from siliceous ores. The silver output of Yavapai
County, which increased from 2,207,583 ounces in 1917 to 2,502,968
ounces in 1918, was mainly derived from copper ores. Bullion recovered
from gold and silver ores, almost all by cyanidation, yielded 158,476
ounces of silver. Concentrates contained 1,109,510 ounces, and crude
ore shipped to smelters contained 5,372,505 ounces, or 80 per cent of
the total output of silver.
CALIFORNIA.
Gold.—The
mine production of gold in California in 1918 was $16,528,953. The
decrease of $3,558,551 was mainly due to a smaller production from
deep-mine operations.
In
1918 the deep mines produced $8,690,174 (a decrease of $2,323,-300), of
which gold-quartz ores yielded 91 per cent and copper ores 3.9 per
cent. California placers in 1918 produced $7,838,779 in gold, or
$1,235,251 less than in 1917. Of the placer production $7,431,927 was
recovered by dredging. The total dredge production from 1896 to the end
of 1918 has been $102,625,912, andthe yield of gold by dredges was
equal to 45 per cent of the total yield of gold for 1918. The Yuba
County dredges, 12 in number, made the largest output of gold, the
value being $3,750,033, an increase of $90,822. Sacramento County,
with 10 dredges working, made an output of $1,690,-279—a decrease of
$223,225., In Butte County (including Oroville and other districts) 7
dredges produced $626,016 in gold, or $272,125 less than in 1917.
Dredges were also operated in Calaveras, Amador, Merced, Stanislaus,
Placer, Shasta, Siskiyou, San Joaquin, and Trinity counties.
Four
of the 29 counties in California which reported mine production of
gold had a yield of more than $1,000,000 in 1918, as follows: Nevada,
$3,07.0,453; Amador, $3,249,385; Yuba, $3,767,933; Sacramento,
$1,694,724. Of these Yuba and Sacramento counties obtained most of
their gold by dredging, Amador is on the Mother Lode, and Nevada County
produced mainly from siliceous ores of the Grass Valley district. The
five Mother Lode counties—Amador, Calaveras, Eldorado, Mariposa, and
Tuolumne—whose output is mainly gold milling ores, produced $2,657,624
in gold from mill bullion and $1,614,455 from concentrates in 1918,
against a recovery of $3,202,212 from mill bullion and $1,888,961 from
concentrates in 1917.
Silver.—The
mine production of silver in California in 1918 was 1,427,711 fine
ounces—a decrease of 347,720 ounces. About 47 per cent of the output,
or 669,711 ounces, came from the copper ores. Siliceous ore3 yielded
228,332 ounces, silver-lead ores, zinc ores, and lead ores 499,759
ounces, and placers the remainder. The only counties producing more
than 100,000 ounces of silver in 1918 were Shasta, Plumas, and Inyo.
About 69 per cent of all the silver was recovered from crude ores sent
to smelters.
COLORADO.
Gold.—The
total mine production of gold in Colorado in 1918 was $12,751,718, a
decrease of $2,977,506, following a decrease in 1917 of $3,424,597. The
Cripple Creek district, with a decrease of $2,275,100, produced
$8,119,747 in gold, which was 64 per cent of the State output of gold
from all sources, and San Miguel district produced $2,127,-634 in gold
in 1918, as against $2,009,961 in 1917.
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