total value of the gold placer output was $22,515,889 in 1910, against
$27,036,705 in 1909. The placer gold output of Alaska was $11,984,806,
against $16,252,638 in 1909, the heaviest decrease in gold output from
Alaska and from the United States and from the placer production as a
whole. The placer gold output of California was 88,888,795 in 1910,
against $9,104,433 in 1909. Placer
production decreased in 1910 also in Colorado, Idaho, and Oregon, but increased in Montana and Nevada.
supplied $9,293,106 in 1910, against $8,783,380 in 1909. California
produced $7,550,254 from dredges in 1910, against $7,382-950 in 1909.
The total production of gold from dredging in California to the end of
1910 has been $40,318,775. In 1910 Alaska produced $800,000, Colorado
$344,210, Idaho $91,247, Montana $473,385, and Oregon $34,010. There
were 113 dredges in all in operation in 1910, of which 72 were in
California, 18 in Alaska, 6 each in Colorado, Idaho, and Oregon, and 5
in Montana. The remainder of the placer output was mainly from drift
mining, which is especially important in Alaska and California, and
from hydraulic and sluicing placers. There is annually also a small
production by hand-washing and a yet smaller output from "dry-washing"
operations in the arid regions of the Southwest. Although numerous
machines have been on trial for these last-named operations, the total
production from this source to date has been small.
Dry and siliceous ores.—In
1910, dry or siliceous ores, including true gold ores, and precious
metal bearing ores not classed as copper, lead, or zinc ores, produced
$65,313,092 in gold, against an output from tills source of $64,341,781
in 1909. States producing over $1,000,000 from these ores in 1910
ranked as follows: Colorado, Nevada, California, South Dakota, Alaska,
Montana, and Arizona, or in the same relative order as in 1909. Notably
increased output from this source