The
output of gold by cyanidation decreased about 21,000 ounces. It was
derived mainly from Colorado, Nevada, Arizona, and South Dakota. The
principal decreases were in Arizona, 25,302 ounces; Colorado, 12,589
ounces; California, 10,859 ounces; and Oregon, 10,351 ounces.
Nevada
led in yield of silver by cyanidation and was followed by Texas, New
Mexico, and Arizona. The most notable losses were in Colorado, 91,839
ounces, and Texas, 153,492 ounces. The only considerable gain was about
11,000 ounces in Nevada.
Of
the gold-producing States whose output is derived chiefly from milling
ores, Alaska, California, "Idaho, and South Dakota still yield more
gold by amalgamation than by cyanidation, but cyanidation produces
more gold than amalgamation in Arizona, Colorado, Montana, and Nevada,
and it produces much more silver in Arizona, Montana, Nevada, New
Mexico, Texas, and Utah. Only in Alaska, California, and South Dakota
did the recovery of silver by amalgamation exceed that by cyanidation.
Altogether amalgamation produced gold and silver valued at $16,030,037
from milling ores in 1921 against $18,815,450 produced by cyanidation.
QUICKSILVER AND POTASSIUM AND SODIUM CYANIDE CONSUMED IN
CERTAIN STATES.
For
details of the consumption of quicksilver in the amalgamation milling
process and of potassium cyanide and sodium cyanide in the cyanidation
process the reader is referred to the mines reports of the several
Western States. The consumption of quicksilver at mills treating ore,
in dredging, and in other methods of placer mining is given in the
separate chapters on quicksilver in Mineral Resources for 1917-1921.
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