434 MINERAL RESOURCES, 1821—PART I.
actually
yielded on remelting 208,622,056.8 fine ounces. The purchases of silver
from domestic mines in 1920 at the price fixed under the Pittman Act
amounted to 29,907,361 fine ounces. The purchases in 1921 by months
were as follows, in fine ounces: January, 4,677,188; February,
4,615,842; March, 5,912,065; April, 4,334,741; May, 6,836,500; June,
4,442,000; July, 4,670,119; August, 4,913,614; September, 3,471,436;
October, 5,917,997; November, 3,447,000; December, 5,424,025; total,
58,662,527. The total purchases under the Pittman Act to December 31,
1921, were 88,569,888 fine ounces. The purchases in the first nine
months of 1922 were as follows, in fine ounces: January, 2,532,000;
February, 3,444,740; March, 6,938,980; April, 6,549,748; May,
4,122,400; June, 5,204,750; July, 2,841,000; August, 8,325,000;
September, 4,377,445. The total purchases under the Act to September
30, 1922, have been 132,905,951 fine ounces, leaving 75,716,106 ounces
to be purchased.
Kesumption
of mining at base-metal mines will increase the quantity of domestic
silver, but it is impossible at present to predict when the total
purchases will reach the total quantity of silver necessary to replace
the silver dollars remelted. From present indications the period
required will probably be about one year from January 1, 1923.
The
domestic supply of new gold comes chiefly from dry or siliceous gold
ores, treated mainly in gold mills by amalgamation or cyani-dation or
both and partly by smelting, and from placer gravels worked largely by
dredges. As shown on page 452 these ores and placer gravels supplied
nearly 95 per cent of the yield of gold in 1921. Considerable gold is
usually recovered also from the refining of copper bullion from copper
ores, especially in the West Mountain or Bingham district, Utah, and
the Summit Valley or Butte district, Mont. In 1921 the copper ores of
the United States produced only 2.25 per cent of the total gold,
against 7.2 per cent in 1920. The natural tendency has been for the
proportionate output from gold ores to decrease with declining yield
from some of the principal gold camps and for that from copper ores to
increase, with a general net decline of total yield of gold owing to
the preponderant output from gold and gold-silver ores. This tendency
was suspended in 1921, owing to the large decrease in the output of
copper.
The
principal domestic supply of new silver came from dry or siliceous
silver and silver-gold ores, copper ores, lead ores, and lead-zinc ores
in the proportion of 51.88, 10.36, 32.30, 4.30 per cent, respectively,
in 1921, against 36.22, 21.49, 30.19, 8.56 per cent, respectively, in
1920. The greater part of the dry and siliceous silver ores is milled
and cyanided at or near the mines, but a small quantity of richer ore
is shipped to copper and lead smelters. The silver obtained as a
by-product from copper, lead, and zinc ores is derived from refining
the copper and lead bullion produced in smelting those and other ores.
WORLD'S PRODUCTION OF GOLD."
The value of the gold produced in the world from 1860 to 1921, inclusive, was $14,004,835,624.
In
1921 the estimated production of gold in the world decreased
$7,145,300, after a decrease of about $28,769,000 in 1920, of
$15,-136,000 in 19.19, and of $38,500,000 in 1918. The production in the
'» See also pp. 513-564.
