The
great bulk of the ore treated was milled in Alaska, South Dakota,
California, Colorado, Nevada, and Arizona, and here the famous mines
and mills of the Homestake, Mother Lode, Grass Valley, Treadwell,
Cripple Creek, Tonopah, Goldfield, and San Francisco (Oatman) districts
are especially noteworthy. Large numbers of smaller mills, however,
mark the wide distribution of gold mining in these regions and in many
other scattered districts.
The
total yield of gold by amalgamation in the United States in 1922 was
812,396 fine ounces, against 765,397 fine ounces in 1921, and there has
been a decrease of about 152,200 ounces since 1916. Appreciable
increases in 1922 were shown in California, Montana, South Dakota, New
Mexico, Washington, and Nevada, and there were decreases in Alaska,
Idaho, Oregon, Colorado, and Arizona.
The
silver produced by amalgamation came mainly from California, South
Dakota, Colorado, Alaska, and Nevada and consisted chiefly of silver
alloyed with gold.
The
output of gold by cyanidation decreased about 18,000 ounces. It was
derived mainly from Colorado, Nevada, Arizona, and South Dakota. The
principal decreases were in Alaska, 6,325 ounces; Arizona, 10,745
ounces; Montana, 5,398 ounces; and South Dakota, 8,398 ounces. There
were increases in California, Colorado, Nevada, New Mexico, Utah, and
Washington.
Nevada
led in yield of silver by cyanidation and was followed by Texas, New
Mexico, and Arizona. The most notable gains were in Nevada, 1,190,011
ounces, and Texas, 125,669 ounces.
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, Nevada, New Mexico,
and Utah, and it produces much more silver in Arizona, Montana, Nevada,
New Mexico, Texas, and Utah. Only in Alaska, California, Colorado,
Idaho, and Oregon did the recovery of silver by amalgamation exceed
that by cyanidation. Altogether amalgamation produced gold and silver
valued at $16,976,835 from milling ores in 1922, against $19,993,823
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 mine 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 1917-1919.
The following tables were compiled by V. C Heikes:
