776 MINERAL RESOURCES, 1915----PART I.
MINE PRODUCTION OF GOLD AND SILVER BY STATES.
ALASKA.
It
is estimated by A. H. Brooks that the total yield of gold from Alaska
from earliest mining, in 1880, to the end of 1915, has been
$260,858,943, of which $186,192,992 has come from placers. The total
silver production has been 4,923,198 fine ounces, of which 2,360,187
ounces was recovered from copper ores and 1,576,823 ounces from the
refining of placer gold.1
Gold.—The
mine production of gold in Alaska in 1915 was $16, 702, 144, an
increase of nearly $1,000,000 more than that of 1914. The yield from
sdiceous ores increased from $4,863,028 in 1914 to $6,069,023 in 1915;
the yield from copper ores decreased from $171,231 in 1914 to $153,121
in 1915. The placer output in 1915 was $10,480,000, against $10,730,000
in 1914. Thirty-five dredges produced $2,330,000 of the placer gold,
which was $20,000 less than the yield from dredging in 1914.
The
production of gold from the Yukon and Kuskokwim basins in 1915 was
about $500,000 less than in 1914; but the output from southeastern
Alaska and Prince William Sound region increased about $1,300,000, that
from Copper River and Cook Inlet regions increased $7,700, and that
from Seward Peninsula and northwestern Alaska increased $185,000. Of
the productive gold lode mines 13 were in southeastern Alaska, 5 on
Prince William Sound, 4 in Kenai Peninsula, 3 in Willow Creek district,
and 3 in Fairbanks district. The 13 deep gold mines in southeastern
Alaska yielded nearly 90 per cent of the gold derived from siliceous
ores.
In
1915 the average value of the gold and silver content of all the
siliceous ores treated was $2.79 a ton. The 3,020,607 tons of siliceous
ores treated in 1915 yielded $2 02 in gold and silver a ton and the
369,600 tons of copper ore contained $1.65 in gold and silver a ton and
had a copper content of 11.7 per cent.
About
38 per cent of the total gold output of Alaska came from lode mines in
1915, against 32 per cent in 1914, 31.6 per cent in 1913, and 29 per
cent in 1912, indicating a more accelerated transition from placer to
lode mining. The 700 placers operated in 1915 yielded approximately
8,100,000 cubic yards of auriferous gravel, of whicb the dredges
handled about 4,600,000 cubic yards and made an average recovery of 51
cents a yard in 1915, against 52 cents a yard in 1914. The estimated
total recovery of gold by dredging for the period 1903-1915, inclusive,
is $12,430,894.
No new placer districts were discovered in 1915, though new ground was opened in regions previously known to be gold bearing.
Silver.—The
mine production of silver in Alaska in 1915 was 1,071,782 fine ounces,
against 394,805 ounces in 1914. The copper mines produced 897,839
ounces, an increase of 614,484 ounces. The siliceous ores yielded
91,341 ounces in 1915, against 28,254 ounces in 191(4, and the placers
82,602 ounces in 1915, against 83,196 ounces in 1914.
i U. S. Geol. Survey Mineral Resources, 1915, pt. 1, p. 179, 1916.
