Sacramento
obtained most of their gold by dredging; Amador and Calaveras are 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 $2,820,455 in gold from mill bullion and
$863,102 from concentrates in 1921, against $2,558,597 from mill
bullion and $862,845 from concentrates in 1920.
Silver.—The
mine production of silver in California in 1921 was 3,629,223 fine
ounces—an increase of 1,922,896 ounces. Siliceous ores yielded
3,329,530 ounces, copper ores 175,870 ounces, lead ores 82,267 ounces,
zinc ores 2,926 ounces, and placers the remainder. The only counties
producing more than 100,000 ounces of silver in 1921 were San
Bernardino and Plumas. About 91 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 1921 was $6,835,328, a
decrease of $740,991, following decreases of $2,310,-308 in 1920,
$2,865,091 in 1919, $2,977,506 in 1918, and $3,424,597 in 1917. The
Cripple Creek district, with a decrease of $32,115, produced $4,291,883
in gold, or 63 per cent of the State output from all sources.
The
San Juan region, in Dolores, La Plata, Ouray, San Juan, and San Miguel
counties, produced $1,597,358; and Lake County produced $309,144, a
decrease of $459,221. Siliceous and dry ores, 96 per cent of all the
ore sold or treated, yielded 93 per cent of the total output of gold; a
little more than 1.5 per cent came from lead ore, 5 per cent from
placers, and the remainder from other classes of ore.
The
placer production in 1921 was $344,640, a decrease of $169,948. Dredges
in Summit County produced more than 98 per cent of the placer gold.
Silver.—The
mine production of silver in Colorado in 1921 was 5,631,657 fine
ounces, an increase of 222,322 ounces. Lake County, principally
Leadville, produced 1,043,497 ounces, a decrease of 56,191 ounces. San
Miguel County produced 1,776,963 ounces, an increase of 712,296 ounces.
Siliceous and dry ores yielded nearly 83 per cent of the silver
recovered, lead ores 9.3 per cent, and copper ores 6.8 per cent. The
remainder came from placers, zinc ores, and copper-lead ores.
IDAHO.
Gold.—The
mine production of gold in Idaho in 1921 was $545,731, an increase of
$60,141. The total production of gold from Idaho from the discovery of
placer gold in 1863 to the end of 1921 is estimated by C. N. Gerry2 at $133,358,344.
Boise
County produced about 47 per cent of the total output in 1921. The lode
mines produced gold valued at $364,131 and the placers at $181,600, of
which $151,762 was won by dredging. The total output of gold recovered
by dredges from 1897 to the end of 1921 has been $4,439,560. Of the
total gold in 1921 about 33 per
> U. R. Geol. Survey Mineral Besources, 1921, pt. 1, p. 399.
