derived,
both from copper ores and from siliceous ores. A reduced copper
production is likely to be felt in a reduced gold production for 1907.
The
silver production was 11,980,705 ounces, a decrease of 1,350,595
ounces. The decrease is about evenly divided between the copper ores of
Butte and the siliceous ores of other counties. Among the latter
Granite, Jefferson, Lewis and Clark, and Cascade are the principal
producers.
Nevada.—Nevada
mines yielded $10,470,704 in gold, an increase of $5,200,885 over 1905.
The unexpectedly heavy output of the Gold-field mines was $7,026,154,
an increase of over $5,000,000 over the preceding year. The Tonopah
district in Nye County produced $1,304,677 in gold, a figure not
materially different from that of 1905. Lincoln County furnished in the
Searchlight and De Lamar (Ferguson) districts an almost equal quantity
of gold. Elko and Storey are the only remaining counties whose output
exceeded $1,000,000. Elko, in the northeastern portion of the State,
maintains a considerable output of siliceous ore from several districts
near or north of Tuscarora. The Comstock output was diminished to about
$300,000. The product is almost wholly from siliceous ores of high
average grade. The placers contributed only about $50,000. An increase
in Nevada gold for 1907 seems probable.
The
silver output was 6,770,611 ounces, an increase of 288,530 ounces,
which was pretty evenly distributed over all of the counties,
corresponding to the general mining activity, only the Comstock mines
in Storey County and White Pine County showed a decline. The Fairview
district changed the insignificant output of Churchill County
(including Douglas) to nearly 200,000 ounces. The Tonopah district was
still the principal producer with 5,697,928 ounces. Of the total output
6,500,000 ounces were derived from siliceous ores. The remainder came
chiefly from lead ores.
New Mexico.—The
gold produced bv the New Mexico mines was valued at $293,019, a
decrease of $24,491. The Mogollon district in Socorro County and the
Pinos Altos district in Grant County are the only regions of important
production. Nearly nine-tenths of the gold was derived from siliceous
ores, the remainder being placer product, and a small amount from
copper ores.
A
fair increase is noted in the silver product, which was now 491,127
ounces, mainly divided between Socorro and Grant counties. This
statement hardly represents the real state of the mining industry,
since there is a large and increasing tonnage of zinc ores which are
very poor in silver or in which the silver is not recovered.
Michigan.—The
mines of Michigan yielded 222,222 fine ounces of silver in 1906, a loss
of 30,789 ounces compared with the output of 1905. This silver, to
which 8 companies contributed, was chiefly-derived from electrolytic
refining of certain grades of Lake copper; part of it came, however,
from "pickings" or metallic lumps saved in the stamp batteries. The
amygdaloid ores contributed about three-fourths of the production, the
remainder coming from the conglomerate lodes. The average value of
silver in the ores is extremely small, rarely rising above 0.038 ounce
per ton of ore. A detailed article on the Lake Superior copper mines
for 1906 is contained in the report on copper production by L. C.
Graton in this volume.
