Twin Creeks Mine
Location: Northern Nevada, United States.
Products: Gold.
Owner: Newmont.
Deposit size: Length 4 km
Width
1 km
Area 3 sq km
Deposit features: Beds or lenses
Dikes or sills
Fault zone
Deposit age geologic: Eocene
Intrusive rock: Dacite porphyry
Ore bearing unit: Pennsylvanian–Permian Etchart
Fm.; Ordovician Valmy
Fm. and Comus Fm.
Ore bearing unit thickness: 3000 m
Tectonic setting: North-American craton rifted
western margin, imbricate structure.
Alteration : Contact
metamorphism (?) decarbonatization, oxidation & silicification (jasperoid)
Associated deposits: sediment-hosted Au
Discovery date: 1984
Operation types: Open pit, Crushing and milling
& Heap leach.
Total tonnage: 223.4tonnes
Contained gold: 484 tonnes
Recovery: Au 80%
Gold grade: 2.67 g/t
Reserves (December 31, 2014): 0.158M
oz. gold
BY -Dr.R.N.Mishra-
Nevada is one of the most
important metal-mining States of the West and has produced large quantities of
gold, silver, and lead. At present her production of precious metals is again
rising rapidly, and although the output of lead is much smaller than formerly
the State is now an important producer of copper. The mining districts number
about 200.
The northern boundary line of
Nevada lies within the province of the Columbia River lava, and these flows of
basalt and rhyolite extend for some distance into the State. At the bend of the
California State line the Sierra Nevada forms the boundary of Nevada and a
small part of that great range is included within its limits.
TWIN CREEKS MINE has
Sediment-hosted gold deposit in Nevada, U.S.A. The USGS recognised the deposit
as Carlin Subtype, manifested as Beds or lenses, Dikes or sills or of Fault
zone kind of mineralisation. The Twin Creek Deposit has been surveyed and the
dimensions are 4 km long x 1 km wide with an area of 3 sq.km. Generally, The
Carlin–type deposits represent some of the largest hydrothermal gold deposits
in the world.
The Carlin type deposits show
enrichment in the elements gold, antimony, mercury, thallium and barium. This
enrichment is created by hydrothermal circulation with a temperature of up to
300 °C. The underlying rocks out of which the minerals are dissolved are
normally silty carbonates, although also silicates and other sediments are
possible. The material in the deposit is altered in a way that the carbonate
minerals are either dissolved or converted to the silicates by silicate rich
hydrothermal water. For example dolomite is transformed into jasperoid. Another
alteration is the formation of clay minerals by interaction of water and
feldspar.
-Dr.R.N.Mishra-
Reference information
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D.R., 1991, Discovery, geology, and mineralization of the Rabbit Creek gold
deposit, Humboldt County, Nevada, in Raines, G.L., Lisle, R.E., Schafer, R.W.,
and Wilkinson, W.H., eds., Geology and ore deposits of the Great Basin,
Symposium Proceedings: Reno, Geological Society of Nevada, p. 821–843.
Breit, F.J., Jr., Ressel, M.W., Anderson, S.D., and Muirhead,
E.M.M., 2005, Geology and gold deposits of the Twin Creeks mine, Humboldt
County, Nevada, in Rhoden, H.N., Steininger, R.C., and Vikre, P.G., eds.,
Symposium 2005—Window to the world: Reno, Nevada Geological Society, p.
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Unpublished.
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1997, 40Ar/39Ar dating and mineral paragenesis for Carlin-type gold deposits
along the Getchell Trend, Nevada—Evidence for Cretaceous and Tertiary gold
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Clarke, L.J., 2000, The geology and gold mineralization of the Twin Creeks gold
deposits, Humboldt county, Nevada, in Crafford, A.E.J., ed., Geology and ore
deposits—The Great Basin and beyond; Geology and ore deposits of the Getchell
region, Humboldt County, Nevada: Geological Society of Nevada Symposium 2000,
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