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MINERAL RESOURCES, 1912.
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lead
ores, 599,110 ounces; and dry and siliceous ores 373,255 ounces.
Bullion at gold and silver mills yielded 45,660 ounces of silver in
1912; concentrates smelted, 387,159 ounces; and crude ore smelted,
2,982,049 ounces.
CALIFORNIA.
Gold.—The
mine production of gold in California in 1912 was $19,713,478, against
$19,738,908 in 1911. The total gold output from placers and from
copper, lead, and zinc ores, decreased in 1912, but the production from
siliceous ores increased nearly in equal amount, the net falling off
for the gold output for the State being only $25,430.
The
deep mines yielded $11,067,815 in gold, of which $10,771,759 came from
siliceous ores (almost wholly gold milling), $293,946 from copper ores,
$1,717 from lead ores, and $393 from zinc ores. The placers produced
$8,645,663, of which $689,682 came from hydraulic mines, $7,429,955
from dredges $387,992 from drift mines, and $138,034 from sluicing
mines.
The
dredges produced 37.68 per cent of the total and 85.93 per cent of the
placer yield in 1912. The total dredge output of California for the
last 14 years has been $55,415,191 in gold. The dredge output has
increased nearly every year, but three decreases being recorded—for
1900, 1907, and 1912. The rate of increase has steadily declined since
1908. The Yuba County field decreased in dredge output by $248,540 in
1912, and Sacramento County by $132,274; but Butte County, as a whole,
increased its yield by $20,232, and the Oroville field alone by $92,935.
The
leading counties in gold production ranked as follows in 1912: Amador,
$2,796,194; Yuba, $2,753,408; Butte, $2,346,229; Nevada, $2,081,958;
Sacramento, $1,712,587; Tuolumne, with $1,113,291. The largest
increases in output were $272,949 in Kern County, $271,475 in Sierra,
and $166,533 in San Bernardino. The largest decreases were $243,664 in
Yuba, $205,187 in Inyo, $150,170 in Calaveras, and $146,673 in Shasta.
Of the counties named, Yuba, Butte, and Sacramento are essentially
dredging counties; Amador, Calaveras, and Tuolumne are Mother Lode
counties; Shasta County produces gold mainly from siliceous and copper
ores; and Nevada County production is mainly from gold-quartz milling
ores of the Grass Valley district. Two of the largest increases, those
in Kern and San Bernardino counties, were from the southern part of the
State.
The
five Mother Lode counties—Amador, Calaveras, El Dorado, Mariposa, and
Tuolumne—whose ores are mainly gold quartz, produced altogether in
1912 gold valued at $4,741,497, against $4,877,651 in 1911 and
$4,408,990 in 1910. The average total gold and silver recovery per ton
from Mother Lode ore in 1912 was $3.69, against $3.57 in 1911, and
$3.78 in 1910.
Silver.—The
production of silver in California in 1912 was 1,300,136 fine ounces,
against 1,270,445 ounces in 1911 and 1,840,085 ounces in 1910. The
larger part of the output—792,445 ounces in 1912 and 864,397 ounces in
1911—came from smelting copper ores. The siliceous gold-silver ores
produced 409,873 ounces in 1912, and the placers, lead ores, and zinc
ores the small remainder. The copper
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