Silver.—The
mine production of silver in California in 1920 was 1,706,327 fine
ounces—an increase of 599,138 ounces. Siliceous ores yielded 1,243,971
ounces, copper ores 179,752 ounces, lead ores 252,704 ounces, and
placers the remainder. The only counties producing more than 100,000
ounces of silver in 1920 were San Bernardino, Plumas, and Inyo. About
78 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 1920 was $7,576,319, a
decrease of $2,310,308, following decreases of $2,865,091 in 1919,
$3,424,597 in 1917, and $2,977,506 in 1918. The Cripple Creek district,
with a decrease of $1,503,818, produced $4,323,998 in gold, or 57 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 $1,654,139; and Lake County produced $768,365, an
increase of $142,409. Siliceous and dry ores, 78 per cent of all the
ore sold or treated, yielded 86 per cent of the total output of gold; a
little more than 3 per cent came from lead ore; nearly 7 per cent from
placers; and the remainder from other classes of ore.
The
placer production in 1920 was $514,588, a decrease of $35,974. Summit
County produced more than 72 per cent and Lake County nearly 27 per
cent of the placer gold. Dredges in these two counties recovered more
than 99 per cent of the placer gold.
Silver.—The
mine production of silver in Colorado in 1920 was 5,409,335 fine
ounces, a decrease of 348,675 ounces. Lake County, principally
Leadville, produced 1,099,688 ounces, a decrease of 442,636 ounces. San
Miguel County produced 1,064,667 ounces, a decrease of 36,275 ounces.
Siliceous and dry ores yielded 67 per cent of the silver recovered,
lead ores 15.6 per cent, lead-zinc ores 13.4 per cent, and copper ores
less than 2 per cent. The remainder came from placers, zinc ores, and
copper-lead ores.
IDAHO.
Gold.—The
mine production of gold in Idaho in 1920 was $485,590, a decrease of
$227,648. The total production of gold from Idaho from the discovery of
placer gold in 1863 to the end of 1920 is estimated at $132,812,613 by
C. N. Gerry.3
Boise
County produced about 55 per cent of the total output in 1920. The lode
mines produced gold valued at $371,776 and the placers $113,814, of
which $101,679 was won by dredging. The total output of gold recovered
by dredges from 1897 to the end of 1920 has been $4,287,798. Of the
total gold in 1920 about 23 per cent came from placers, 58 per cent
from siliceous ores, 6 per cent from copper ores, and the remainder
from lead, copper-lead, and lead-zinc ores.
Silver.—The
mine production of silver in Idaho in 1920 was 7,326,794 fine ounces,
or 1,747,738 ounces more than in 1919. The total silver from Idaho for
the period 1863 to 1920, inclusive, amounts to 246,784,145 fine ounces.3
