102-484, which authorized the disposal of
the entire inventory of zinc from the
National Defense Stockpile (NDS). The
Defense Logistics Agency (DLA), which
maintains the NDS, was authorized to sell
68,000 tons in FY 1993 and 43,545 tons
in FY 1994; it sold 19,000 tons during
calendar year 1993.
Production
Mine Production.-U.S. zinc mine
output decreased 8% in 1993, despite
higher production at the Red Dog Mine in
Alaska. This was a result of several
mine closures. The 20 leading mines
accounted for more than 98 % of
production, with S leading mines
accounting for 75 %.  For the third
consecutive year, Alaska was the leading
zinc-producing  State,  followed  by
Tennessee, New York, Missouri,
Colorado, and Montana. The leading
domestic producers were ASARCO
Incorporated, Cominco Alaska Inc.,
Union Zinc Co., and Zinc Corporation of
America (ZCA).
The Red Dog Mine in northwestern
Alaska and the Greens Creek Mine on
Admiralty Island accounted for nearly all
zinc production in Alaska in 1993. The
Red Dog Mine, which began operations
in late 1989, is owned by NANA
Regional Corp. Inc. and leased to
Cominco Alaska Inc., a subsidiary of
Cominco, Ltd., which owns and operates
the mining and processing facilities.
NANA is paid a royalty that is scheduled
to increase after the capital investment
plus interest is recovered by Cominco.
In 1993, the grinding circuit was
improved,   resulting  in  increased
production. By the end of the year, zinc
concentrate production was at design
capacity. An expansion of the grinding
circuit was initiated late in the year and
completed   early  in   1994,  and
improvements were made to the
concentrator circuit. Zinc concentrate
production was expected to be above
design capacity in 1994. According to
the Cominco annual report, zinc recovery
was 81%, up 5% from 1992, and total
ore milled was 1,700,600 tons, or
265,400 tons more than in 1993. The


ore grade was 18.4% zinc, down 1.5%
from last year. A total of 235,200 tons
of zinc in zinc concentrate and bulk lead-
zinc concentrate was produced in 1993,
an increase of 17,000 tons from 1992.
Ore reserves at yearend were 56.8
million tons averaging 18.4 % zinc, 5.7 %
lead, and 93 grams per ton silver. An
additional 14.1 million tons of lower-
grade ore was classified as inferred
reserves.
The Greens Creek Joint Venture is a
consortium 53% owned by RTZ Ltd,
through its Kennecott subsidiary, Greens
Creek Mining Co.; and 47% owned by
minority partners Hecla Mining Co.,
Exalas Resources Corp., and CSX Alaska
Mining Inc. The mine was closed in
April because of low metal prices. It
produced 5,200 tons of zinc in
concentrates, according to the RTZ
annual report.    Development and
engineering activity continued at the
mine.
In Tennessee, zinc was produced at
seven underground mines, four owned by
Asarco in the eastern part of the State and
three owned by Jersey Miniere Zinc Co.
(JMZ) in the western part. Asarco's
production was 56,000 tons of zinc in
concentrates, down 11,900 tons from
1992. Asarco's ore reserves at yearend
were 4.8 million tons averaging 3.28%
zinc. The drop in production was caused
by the failure of a ball mill at Asarco's
Young Mine in late July, which was not
repaired until November.  This also
forced the temporary closure of three of
the company's mines for the same period.
JMZ reduced output from its Jefferson
City Mine by 25 % in July because of low
metal prices and declining reserves.
In Missouri, zinc was produced as a
coproduct of lead at nine underground
lead mines along the Viburnum Trend by
three companies, Asarco, The Doe Run
Co., and Cominco American Inc., a
subsidiary of Cominco Ltd. According to
the Asarco annual report, production of
zinc in concentrate at the West Fork and  I
Sweetwater Mines was 15,900 tons, an
increase of 2,000 tons. Ore reserves at 4
yearend  were  23.7  million  tons, I
averaging 0. 86 % zinc. Zinc output at the a
Magmont Mine, a joint venture of i


Cominco American and Dresser
Industries, continued to drop as the ore
body was nearly depleted; the mine was
scheduled to be closed in 1994.
According to the Cominco annual report,
the Magmont mill processed 630,000 tons
of ore grading 1.2% zinc, yielding 6,200
tons of zinc in 10,200 tons of
concentrate. At yearend, the ore reserves
were 2.5 million tons, averaging 8.3%
lead, 1.2% zinc, and 0.3% copper.
In Colorado, zinc was produced only
as a coproduct of gold-silver operations at
the Leadville Unit, managed by Asarco,
but owned jointly with the Resurrection
Mining Co.   Production of zinc in
concentrate was 13,900 tons.   At
yearend, ore reserves were 635,000 tons,
averaging 8. 1 % zinc.
In Montana, the Montana Tunnels
Mi nig Co., a subsidiary of Pegasus Gold
Inc., milled 4.6 million tons of ore in
1993, containing 16,300 tons of zinc,
6,350 tons of lead, 2,137 kilograms of
gold, and 43,545 kilograms of silver.
Zinc recovery was 88%, with the mill
feed averaging 0.52% zinc. At yearend,
proven and probable reserves were 32.4
million tons, grading 0.60% zinc, 0.22%
lead, 0.6 gram of gold per ton, and 10
grams of silver per ton. The reserves are
lower than in 1992 because material
containing less than 0.5 gram gold per
ton is being stockpiled for processing
when economic conditions are more
favorable.
In January, Equinox Resources Ltd.,
placed its Van Stone Mine in Washington
on a care and maintenance basis because
of low metal prices. The mine had
reopened in August 1992 after being
closed for 9 months. The mine had an
annual production capacity of 14,000 tons
of zinc in concentrates.
In September, Exxon Coal & Minerals
Co. formed a 50-50 joint venture with
Rio Algom Ltd., of Canada, to develop
the Crandon zinc-copper deposit in
Northeastern Wisconsin. The companies
began permitting procedures early in
1994 and anticipated beginning shipments
of concentrates by the end of 1999.
Development of this project was to
require a capital expenditure of $300
million. The deposit has reserves of 27


1280


ZINC-1993






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