" Porto Rico and Philippine Islands excluded.
i>
Recovered by chlorination, 5,769.83 ounces of gold and 3,631 ounces of
silver in California. Value of gold recovered by chlorination was
$119,173, that of silver, $3,631.
c Part of ore amalgamated followed by cyanidation of new tailings. Total ore and new tailings cyanided, 1,161,161 tons.
Figures
corresponding to those in this table were collected and compiled for
the entire United States by the Geological Survey for the first time in
1911, and comparison for eight years can therefore now be made.
The
total quantity of crude ore treated and old tailings re-treated in gold
and silver mills was 8,524,496 short tons in 1918, against 11,076,211
tons in 1917, 11,393,838 tons in 1916, 11,878,287 tons in 1915,
9,849,085 tons in 1914, 9,401,856 tons in 1913, 9,677,360 tons in 1912,
and 9,670,483 tons in 1911. In 1918 ores from Alaska, South Dakota,
Colorado, California, and Nevada treated at gold and silver mills
amounted to about 92 per cent of the total quantity.
The
great bulk of the ore treated, as shown, was milled in Alaska, South
Dakota, Colorado, California, and Nevada, in the order named, and here
the famous mills of the Homestake, Mother Lode, Grass Valley,
Treadwell, Cripple Creek, Tonopah, and Goldfield mines are especially
in evidence. 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 1918 was
678,359 fine ounces, valued at $14,022,925, against 828,681 fine
ounces, valued at $17,130,357, in 1917, and 964,589 ounces, valued at
$19,939,824, in 1916. The output in 1918 was 283,293 ounces in
California, 202,219 ounces in South Dakota, 116,363 ounces
