Hansen Creek Deposit

Producer in Humboldt county in Nevada, United States with commodities Gold, Silver, Arsenic, Tungsten, Antimony, Mercury, Barium-Barite, Molybdenum, Fluorine-Fluorite, Thallium, Tellurium, Bismuth, Tin, Lead, Zinc, Copper

Sections on this page

Identification information
Geographic coordinates
Site location context
Geographic areas
Public Land Survey System information
Commodities
Materials information
Alteration
Mineral occurrence model information
Host and associated rocks
Nearby scientific data
Geologic structures
Ore body information
Controls for ore emplacement
Economic information about the deposit and operations
Mining district
Land status
Ownership information
Bibliographic references
General comments
Reporter information

Geologic information

Identification information

Deposit ID	10310490
Record type	Site
Current site name	Hansen Creek Deposit
Alternate or previous names	satellite deposit of Getchell Gold Mines
Related records	10310336, 10310488

Geographic coordinates

Geographic coordinates:	-117.25874, 41.20989 (WGS84)
Elevation	1710
Relative position	The Getchell Mine is located in Potosi Mining District, about 45 miles (70 kilometers) northeast of Winnemucca, Nevada. Access to the property is by paved road from the main Interstate Highway, I-80.

Site location context

Political divisions (FIPS codes)

Humboldt(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Adam Peak(quadrangle 1:24,000 scale)

Osgood Mountains(quadrangle 1:100,000 scale)

McDermitt(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Middle Humboldt(hydrologic unit)

Humboldt(hydrologic accounting unit)

Black Rock Desert-Humboldt(hydrologic subregion)

Great Basin(hydrologic region)

Geographic areas

Country	State	County
United States	Nevada	Humboldt

Public Land Survey System information

Meridian	Township	Range	Section	Fraction	State
Mount Diablo	038N	042E	04, 09		Nevada
Mount Diablo	039N	42E	28, 29, 32, 33		Nevada

Comments on the location information

UTM is to center of Main Pit, which has encompassed earlier South and Central pits.

Commodities

Commodity	Importance
Gold	Primary
Silver	Primary
Arsenic Critical	Secondary
Tungsten Critical	Tertiary
Antimony Critical	Tertiary
Mercury	Tertiary
Barium-Barite Critical	Tertiary
Molybdenum	Tertiary
Fluorine-Fluorite Critical	Tertiary
Thallium	Tertiary
Tellurium Critical	Tertiary
Bismuth Critical	Tertiary
Tin Critical	Tertiary
Lead	Tertiary
Zinc Critical	Tertiary
Copper	Tertiary

Comments on the commodity information

Ore Materials: native gold, native silver, electrum
Gangue Materials: realgar, orpiment, pyrite, scheelite, pyrrhotite, arsenopyrite, marcasite, magnetite, stibnite, ilsemmanite, cinnabar, hubnerite, calcite, chabazite, sericite, chlorite, barite, gypsum, fluorite, getchellite, galkhaite, laffittite, arsenolite, guerinite, haidingerite, pharmacolite, weilite, coloradoite, bismuthinite, cassiterite, molybdenite, ferrimolbdite, galena, sphalerite, covellite, chalcocite, garnet, epidote

Materials information

Materials	Type of material
Gold	Ore
Silver	Ore
Electrum	Ore
Orpiment	Ore
Pyrite	Ore
Scheelite	Ore
Pyrrhotite	Ore
Arsenopyrite	Ore
Marcasite	Ore
Magnetite	Ore
Stibnite	Ore
Ilsemannite	Ore
Cinnabar	Ore
Hubnerite	Ore
Calcite	Ore
Chabazite	Ore
Sericite	Ore
Chlorite	Ore
Barite	Ore
Gypsum	Ore
Fluorite	Ore
Getchellite	Ore
Galkhaite	Ore
Laffittite	Ore
Arsenolite	Ore
Guerinite	Ore
Haidingerite	Ore
Pharmacolite	Ore
Weilite	Ore
Coloradoite	Ore
Bismuthinite	Ore
Cassiterite	Ore
Molybdenite	Ore
Ferrimolybdite	Ore
Galena	Ore
Sphalerite	Ore
Covellite	Ore
Chalcocite	Ore
Garnet	Ore
Epidote	Ore
Realgar	Gangue

Alteration

(Local) Alteration comments: there is a metamorphic aureole around the Osgood Mountains granodiorite which has produced in the surrounding shaly rocks a mineral assemblage consisting of cordierite-, biotite-, and andalusite-hornfels. Locally limy beds are recrystallized and calc-silicate minerals are developed. Hydrothermal alteration consists chiefly of decarbonatization accompanied by silicification in the limestone beds. Cordierite, andalusite, and biotite of the metamorphic aureole are altered to sericite and/or chlorite. Igneous dikes and portions of the main stock are altered such that plagioclase is altered to sericite and kaolinite and biotite is altered to sericite, chlorite, and pyrite.

Mineral occurrence model information

Model code	173
USGS model code	26a.1
Deposit model name	Sediment-hosted Au
Mark3 model number	17

Host and associated rocks

Host or associated

Host

Rock type

Sedimentary Rock > Clastic Sedimentary Rock > Shale

Rock unit name

Preble Formation

Stratigraphic age (youngest)	Late Cambrian
Stratigraphic age (oldest)	Middle Cambrian

Host or associated

Host

Rock type

Sedimentary Rock > Carbonate > Limestone

Rock type qualifier

silty

Rock unit name

Preble Formation

Stratigraphic age (youngest)	Late Cambrian
Stratigraphic age (oldest)	Middle Cambrian

Host or associated

Associated

Rock type

Plutonic Rock > Granitoid > Granodiorite

Rock unit name

Osgood Mountains pluton

Stratigraphic age (youngest)	Late Cretaceous
Chronological age	90

Nearby scientific data

(1)	-117.25874, 41.20989	ListMap

Economic information

Geologic structures

Type of structure	Local
Structure description	Gold mineralization is generally found at the intersection of a number of high-angle and low-angle fault sets. The low-angle faults and associated folds are the result of Devonian and Permian-age compressional events and the higher angle faults and fracture sets formed during Tertiary extension. Mineralization is both structurally and stratigraphically controlled. The Getchell fault is a zone of overlapping fractures which have an overall strike of N10W. Hotz and Willden (1964) offer evidence for up to 3500 feet of left lateral strike slip displacement and only a relatively small amount of dip slip movement along the Getchell fault. McCollum and McCollum (1991) indicate that the sense of movement on the Getchell fault is right lateral.
Type of structure	Regional
Structure description	thrust faults to the north and NNW-trending faults.

Ore body information

General form Individual orebodies are roughly tabular

General form	Individual orebodies are roughly tabular

Controls for ore emplacement

Economic amounts of gold are restricted to tabular sheet-like zones (termed "veins" by Joralemon) within the Getchell fault zone and within favorable calcareous lithologies.

Comments on the geologic information

Geology comments: Bagby and Cline (1991) offer preliminary results from research which indicate that confining pressures on the Getchell ore system varied from approximately 370-430 bars either during, or at some time subsequent to mineralization. These fluid pressures are greater than those which are normally accepted as epithermal.

Economic information about the deposit and operations

Operation type	Surface
Development status	Producer
Commodity type	Both
Deposit size	Medium
Significant	Yes
Discovery year	1933
Discoverer	Edward Knight and Emmet Chase
Year of first production	1938
Year of last production	1999
Production years	1938-1945; 1948-1950; 1962-1967; 1985-1999

Mining district

District name	Potosi District
District name	Getchell District

Land status

Ownership category	Private
Ownership category	BLM Administrative Area
Area name	Winnemucca BLM Administrative District

Ownership information

Type Owner-Operator

Owner Placer Dome Gold

Year 2003
Type Owner-Operator

Owner Newmont Gold Mining Company

Year 2003

Type	Owner-Operator
Owner	Placer Dome Gold
Year	2003

Type	Owner-Operator
Owner	Newmont Gold Mining Company
Year	2003

Comments on the workings information

The mine has been developed by both underground and surface workings at various times during its production history.
The Getchell deposit was developed by the North, Center, South, and Hansen Creek Pits

Comments on other economic factors

From 1938 to1996 the Getchell property produced 66.8 kilotonnes of gold and more than 1.2 kilotonnes of silver from 18361 kilotonnes of ore.

In 1997, the remaining Getchell resource was estimated at 14,400 kilotonnes of ore containing 153 kilotonnes of gold and an unknown amount of silver and arsenic.

This resource includes Getchell underground, stockpiles, unmineable resource in Main Pit, and North Getchell underground resource.

Comments on development

Prospectors Edward Knight and Emmet Chase discovered gold in 1933 and located the first claims in 1934. With the financial backing of Noble Getchell and George Wingfield, the Getchell Mine, Inc. was organized in 1936 and was brought into production in 1938. In 1938, the mining rate was about 500 tpd of oxide ore and 150 tpd of sulfide ore. Sulfide ore was roasted at 1500 degrees Fahrenheit for one hour and fifteen minutes preparatory to cyanidization. In 1941, a Cottrell electric precipitating unit was installed to save the arsenic that was liberated by roasting the sulfide ore, and in 1943-45, when government wartime restrictions forced the shutdown of many gold producers, Getchell mine was permitted to continue operations as a producer of "strategic" arsenic. In 1943, arsenious oxide was being produced at the rate of 10-25 tpd from furnace fume. Also in 1942, a 227 tonne scheelite flotation plant was built to recover tungsten from Getchell ore. A slack labor supply, and high supply costs forced the gold operations to cease at the end of World War II. The US Bureau of Mines developed a carbon recovery process on site and the mine reopened in 1948 with expanded mill capacity and more underground development, but closed again in mid-1950 when known oxide reserves were exhausted. Gold production was suspended in 1951. From 1951-56, the mill processed tungsten ores mined from throughout the district. Tungsten production ceased in 1957. in 1960, Goldfield Consolidated Mines Co. purchased the interests in Getchell Mine, Inc. from the estates of Wingfield and Getchell. Gold production resumed in June 1962 and continued to December, 1967, when the mine was closed and the mill dismantled. Cyprus Mines formed a joint venture with Goldfield in 1970, with Cyprus as operator. Cyprus dropped the property at the end of 1971. Conoco leased the property from Goldfield in 1972 and completed exploration including over 300 drill holes. Metallurgically difficult sulfide reserves were identified during this program. Conoco subleased the property from 1975 to 1978 to General Electric Co. who conducted tungsten exploration along the margins of the Osgood Stock. In 1981, Conoco purchased the property from Goldfield Corp., but by 1983 had sold the property to First Mississippi for $5 million. At that time the property consisted of 14,100 acres of fee land and almost 5000 acres of unpatented claims, and reserves at the time of purchase were in excess of 750,000 ounces of gold. Mining feasibility and metallurgical studies were initiated in 1984. Heap leaching of waste rock dumps from previous mining operations commenced at the end of fiscal 1985, producing 91 ounces of gold in that fiscal year. By mid-1985, the Getchell property had increased the area of unpatented claims to 13,900 acres. In May, 1987, the board of First Mississippi Corp. authorized open pit mine development and construction of a new mill utilizing autoclave technology to process 3000 tons of ore per day. The mill was completed and production resumed in 1989 combining a traditional cyanide leach circuit with pressure oxidation. The mill started up on oxide ore in February, 1989. Sulfide ore was run through the first pressure oxidation autoclave in April, 1989 followed by the start up of the other two autoclaves in May and June, 1989. By the end of fiscal year 1989, project capital costs stood at $90.3 million, 14% over the June 1987 feasibility study estimate. In fiscal year 1989, overall gold recovery for combined oxide and sulfide mill ores was 89.8%. Heap leaching of waste rock from previous mining operations was completed in fiscal year 1989. Heap leaching continued beyond this date using oxide reserves from the Summer Camp orebody discovered in 1985.
Production of oxide open pit ore commenced at the nearby Turquoise Ridge mine in 1991 and in the same year, an underground orebody adjacent to the pit area. This ore was to be mined when the pit level was deep enough to provide lateral access. In 1995, FirstMiss Gold changed its name to Getchell Gold. Underground production commenced at Turquoise Ridge Mine in May 1998. On May 27, 1999 Placer Dome completed a merger with Getchell Gold Corporation, resulting in Placer Dome owning 100% of the Getchell gold property. Gold production has been suspended since July 1999 and the property is on care and maintenance. Production from approximately 58% of the property is subject to a 2% net smelter return royalty payable to Franco Nevada Mining Corporation Ltd. Placer Dome wrote off the carrying value of the property in 2001. On October 25, 2001, Newmont Mining Corporation and Getchell Gold Corporation signed a letter of intent under which Newmont would buy ore from the Getchell mine for processing at Newmont's adjacent Twin Creeks mine.

Reference information

Bibliographic references

Deposit

McCollum, L. B. and McCollum, M., 1991, Paleozoic rocks of the Osgood Mountains, Nevada, in Raines, G. L., et al, eds., Geology and Ore Deposits of the Great Basin, The Geological Society of Nevada, Reno, p. 735-738.
Deposit

Bagby, W. C. and Cline, J. S., 1991, Constraints on the pressure of formation of the Getchell gold deposit, Humboldt County, Nevada, as interpreted from secondary-fluid-inclusion data, in Raines, G. L., et al, eds., Geology and Ore Deposits of the Great Basin, The Geological Society of Nevada, Reno, p. 793-804.
Deposit

Madden-McGuire, D. J., 1991, Stratigraphy of the limestone-bearing part of the lower Cambrian to lower Ordovician Preble Formation near its type locality, Humboldt County, North Central Nevada, in Raines, G. L., et al, eds., Geology and Ore Deposits of the Great Basin, The Geological Society of Nevada, Reno, p. 875-893.
Deposit

Berger, B. R. and Tingley, J. V., 1985, History of discovery, mining, exploration of the Getchell mine, Humboldt County, Nevada, in Hollister, V. F., ed., Discoveries of epithermal precious metal deposits, case histories of mineral discoveries vol. 1, Society of Mining Engineers, New York, P. 49-51.
Deposit

Berger, B. R., 1985 Geological and geochemical relationships at the Getchell Mine and vicinity, Humboldt County, Nevada, in Hollister, V. F., ed., Discoveries of epithermal precious metal deposits, case histories of mineral discoveries vol. 1, Society of Mining Engineers, New York, p. 51-59.
Deposit

Dunning, Gail E., 1988, calcium arsenate minerals new to the Getchell Mine, Nevada, The Mineralogical Record, Vol. 19, No. 4, p. 253-257.
Deposit

Erickson, R. L., Marranzino, A. P., Oda-Uteana, and Janes, W. W., 1964, Geochemical exploration near the Getchell Mine, Humboldt County, Nevada, USGS Bulletin 1198-A, 26 pp.
Deposit

Hardy, R. A., 1940 Geology of the Getchell Mine, AIME Technical Publication No. 1240, 3 Pp.
Deposit

Wise, F. and Wark, C. W., 1940, Metallurgy and milling practice at Getchell Mine, AIME Technical Publication 1260, 9 Pp.
Deposit

First Mississippi Corp., Annual Reports for fiscal years 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991.
Deposit

NBMG, 1994, MI-1993
Deposit

Nevada Division of Minerals, 1994
Deposit

Long, K.R., DeYoung, J.H., Jr., and Ludington, S.D., 1998, Database of significant deposits of gold, silver, copper, lead, and zinc in the United States; Part A, Database description and analysis; part B, Digital database: U.S. Geological Survey Open-File Report 98-206, 33 p., one 3.5 inch diskette.
Deposit

Placer Dome Gold Company website, 2003

General comments

Subject category	Comment text
Deposit	The known gold deposits within the Getchell Trend are Carlin- type, sediment-hosted, replacement deposits containing micron gold. Gold mineralization is found in a number of different rock types generally at the intersection of a number of high-angle and low-angle fault sets. The low-angle faults and associated folds are the result of Devonian and Permian-age compressional events and the higher angle faults and fracture sets formed during Tertiary extension. Mineralization is both structurally and stratigraphically controlled. Gold is associated with arsenic, mercury, and to a lesser extent antimony, and commonly with pervasive decalcification, silicification and carbonaceous alteration. Gold is micron-scale generally intergrown with arsenical pyrite, which in turn, is encrusted in barren, diagenetic pyrite. Late stage realgar and orpiment are commonly associated with high-grade ores. The main deposit is confined to a zone nearly 7000 ft. long at the northern end of the Getchell fault zone. Deep exploration shows that the mineralization persists at least 1 km down-dip on the Getchell fault system and also occurs along the parallel Village fault. Maximum width of ore is 200 ft., with an average width of 40 ft. Within ore zones, gold occurs as native grains that range in size from <1 micron to nearly 1 mm, with smaller grains more abundant than larger grains. Most of the gold is intimately associated with the fine grained quartz-carbon matrix of the altered rock termed "gumbo" by Joralemon (1951). Of the sulfides, pyrite and marcasite are principal hosts to gold. As of 1951, the gold:silver ratio in bullion ranged from 2:1 to 134:1 and averaged 10:1 for the entire bullion production to that date. Joralemon (1951) observed microscopic metallic grains in the Getchell ore that he concluded were native silver, although the particles were so small that conclusive chemical tests were not possible. No other silver minerals have been recognized except for very rare grains of electrum. Geochemical work at the Getchell mine and vicinity has demonstrated that As-W-Hg anomalies occur in rocks and soils over the arsenic-gold deposits and that these anomalies are not broad haloes but are restricted to the mineralized area. The highest metal contents are found in oxidized iron-rich material along fractures and bedding planes in barren bedrock, lesser values in caliche coatings on exposed bedrock, and lowest but still anomalous values in soil.

Subject category

Comment text

Deposit

The known gold deposits within the Getchell Trend are Carlin- type, sediment-hosted, replacement deposits containing micron gold. Gold mineralization is found in a number of different rock types generally at the intersection of a number of high-angle and low-angle fault sets. The low-angle faults and associated folds are the result of Devonian and Permian-age compressional events and the higher angle faults and fracture sets formed during Tertiary extension. Mineralization is both structurally and stratigraphically controlled. Gold is associated with arsenic, mercury, and to a lesser extent antimony, and commonly with pervasive decalcification, silicification and carbonaceous alteration. Gold is micron-scale generally intergrown with arsenical pyrite, which in turn, is encrusted in barren, diagenetic pyrite. Late stage realgar and orpiment are commonly associated with high-grade ores. The main deposit is confined to a zone nearly 7000 ft. long at the northern end of the Getchell fault zone. Deep exploration shows that the mineralization persists at least 1 km down-dip on the Getchell fault system and also occurs along the parallel Village fault. Maximum width of ore is 200 ft., with an average width of 40 ft.
Within ore zones, gold occurs as native grains that range in size from <1 micron to nearly 1 mm, with smaller grains more abundant than larger grains. Most of the gold is intimately associated with the fine grained quartz-carbon matrix of the altered rock termed "gumbo" by Joralemon (1951). Of the sulfides, pyrite and marcasite are principal hosts to gold. As of 1951, the gold:silver ratio in bullion ranged from 2:1 to 134:1 and averaged 10:1 for the entire bullion production to that date. Joralemon (1951) observed microscopic metallic grains in the Getchell ore that he concluded were native silver, although the particles were so small that conclusive chemical tests were not possible. No other silver minerals have been recognized except for very rare grains of electrum.
Geochemical work at the Getchell mine and vicinity has demonstrated that As-W-Hg anomalies occur in rocks and soils over the arsenic-gold deposits and that these anomalies are not broad haloes but are restricted to the mineralized area. The highest metal contents are found in oxidized iron-rich material along fractures and bedding planes in barren bedrock, lesser values in caliche coatings on exposed bedrock, and lowest but still anomalous values in soil.

Reporter information

Type	Date	Name	Affiliation	Comment
Reporter	01-JUN-2005	LaPointe, D.D.	Nevada Bureau of Mines and Geology
Editor	01-SEP-2007	Schruben, Paul G.	U.S. Geological Survey	Converted from S&A FileMaker format to Oracle. Edit checks on rocks, units, and ages with Geolex search, and other fields.

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