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 36.22, 21.49, 30.19, 8.56 per cent, respectively,
in 1920, against 36.69, 24.82, 27.65, 10.16, respectively, in 1919. The
bulk of the dry and siliceous silver ores are milled and cyanided at or
near the mines, although a small quantity of richer ore is shipped to
copper and lead smelters. The silver obtained as 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 in 1920 was $334,-987,600, and the value from 1860 to 1920, inclusive, was $13,672,-929,924.
In
1920 the estimated production of gold in the world decreased
$30,801,000, following a decrease of about $38,500,000 in 1918 and of
$15,136,000 in 1919. The production in the United States decreased
about $9,146,000; Mexico, $411,000; Africa, $6,004,000; Australasia,
$3,262,000; India, $1,458,000.
In the following table is shown the output of gold, by countries, as given by the Bureau of the Mint:
World's production of gold, 1916-1920.
