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GOLD AND SILVER.
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averaged
15.61 ounces of silver a ton, supplied nearly 32 per cent of the
silver, and concentrates, which averaged 19.66 ounces of silver a ton,
contained nearly 68 per cent of the total silver. Inability to handle
and smelt all the ores mined had the effect of curtailing the
production of silver.
MAINE, PENNSYLVANIA, NEW HAMPSHIRE, NEW YORK, AND VERMONT.
A
small quantity of gold and about 11,107 ounces of silver were obtained
from copper ores and old slag shipped from the Pike Hill, Ely, and
Elizabeth mines in Vermont, the Douglas mine at Blue Hill in Maine, and
from zinc-lead ore containing silver shipped from the Silver Lake mine
in Carroll County, N. H., and a few tons of silver-bearing galena
shipped from Sullivan County, N. Y., by the Summit-ville Ore
Concentrating Co.
MICHIGAN.
Silver.—The copper mines of Michigan produced 509,467 fine
unces of silver in 1918, against 688,551 fine ounces of silver in 1917.
The silver was mainly derived from the electrolytic treatment of
56,127,000 pounds of copper. The average recovery of silver per ton
of "rock" treated was 0.18 ounce a ton. Of the total output of silver
453,957 ounces came from mines in Houghton County.
MISSOURI', OKLAHOMA, ILLINOIS, AND KENTUCKY.
Silver.—The
lead and zinc mines of the Central States produce no gold and only a
comparatively small quantity of silver. Nearly all the silver is a
by-product from the refining of lead from concentrates of lead ores
mined in southeastern Missouri. The total yield of silver from Missouri
in 1918 was 46,939 fine ounces, which, with the exception of 7,892
ounces recovered from copper ore and copper concentrates, was derived
from lead recovered from 52,000 tons of galena concentrates. The
average recovery was slightly more than 0.75 ounce of silver per ton of
concentrate smelted.
The
lead-zinc fluorspar deposits of the Kentucky-niinois field carry
silver, and from the lead concentrates shipped from Illinois in 1918, a
recovery of 8,171 ounces was recorded, against 7,186 ounces in 1917.
The average silver content per ton recovered from lead concentrates
from Illinois in 1918 was 6.65 ounces. No silver ore was shipped from
the Criswell mine, near Byars, McClain County, Okla., in 1918.
MONTANA.
Gold.—The'
mine production of gold in Montana decreased from $3,517,253 in 1917 to
$3,104,764 in 1918. The placer yield was $396,232—a decrease of
$70,831. Silver Bow County had the largest total output—$902,094. Most
of the placer gold was recovered by one company, which operated three
dredges in Alder Gulch, in Madison County. Lewis and Clark County
produced $634,497, and Deer Lodge County $453,083, chiefly from
siliceous ores. At amalgamation and cyanidation plants $930,309 in
gold was produced, or an average recovery of $5.32 per ton of ore and
tailings treated. Ore
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