total value of the gold produced from placers was $14,560,770 in 1919
against $15,673,424 in 1918. The placer production in Alaska decreased
by 44,989 ounces, owing to the scarcity of labor and the high cost of
supplies. The decrease in placer gold from Montana was 5,070 ounces;
from Nevada, 4,165 ounces; from Oregon, 5,689 ounces; from Idaho, 4,144
ounces. The only States showing a considerable increase in gold
produced from placers were California, with an increase of 9,400
ounces, and Colorado, with 1,178 ounces.
placer gold is derived chiefly from dredging, from drift mining (which
is of decreasing importance in Alaska in frozen ground at no
great depth, but of
continued importance in California in ancient buried river channels,
often at considerable depth), and from hydraulic and sluicing placers.
In California, especially, hydraulic mining was of much importance in
the past and had become a special branch of the industry in itself, but
restrictive laws relative to the debris and to disturbance of navigable
streams have in recent years greatly confined mining activity of this
kind. Finally, there is a small annual output of gold from dry placers
in the Southwest and also a production of gold and platinum from
ocean-beach mining in California and Oregon.
Some interesting notes on beach mining in California and Oregon and on dry placers in California, by Charles G. Yale, and on dry