Emigrant Springs

Sediment-hosted gold deposit in Nevada, U.S.A.

Geologic information

CountryU.S.A.
State or provinceNevada
Geographic location:40°37'5"N, 115°58'24"W
(-115.973333, 40.618056)
(click for info)
SubtypeCarlin
Deposit size
Length2km
Width0.6km
Thickness91m
Area0.9sq km
Deposit features
Beds or lenses
Dikes or sills
Fault zone
Ore breccia
Deposit age geologicEocene
Deposit clusterCarlin Trend
Geochemical indicatorsAs, Au, Ba
Intrusive rockmonzonite porphyry
Intrusive rock age37.5±0.8, U-Pb SHRIMP Ma
Ore bearing unitLower Mississippian Webb Fm., bottom part
Ore bearing unit thickness150 m
Tectonic settingNorth-American craton rifted western margin, foreland basin related to Antler orogeny
Minerals
Gold-bearing minerals:
Ore minerals:
Gangue minerals:
Alteration
Associated depositssediment-hosted Au
Geologic map unit-115.973333333333, 40.6180555555556
Nearby scientific dataFind additional scientific data near this location

Economic information

Statusmining operations
Owner or operatorNewmont Gold Co.
Discovery date1982
Startup date2012
Gold particle size≤1; visible
Operation types
Open pit
Heap leach
Total tonnage62tonnes
Contained gold37.3 tonnes
Recovery Au58%
Source of tonnage, gradeNewmont (2009); Doxey and others (2005)

Silver grade

SilverUnitsCriteria
0g/tAll ore in deposit

Gold grade

GoldReservesResourcesUnitsCriteria
0.62g/tOre amenable to open-pit mining
0.62g/tAll ore in deposit

Gold cut-off grades

ReservesResourcesUnitsCriteria
0.1g/tOre amenable to open-pit mining

Reserves and Resources

Mining methodEstimate typeTonnageCriteria
Open pitReserve61.72005, proven+probable

Reference information

Comments

According to Newmont (2009), the undeveloped reserves at the Emigrant deposit consist of 1.2 million ounces of gold (37.3 t Au). Ore-bearing Webb Fm. overlies eroded karstic paleosurface of Devils Gate Limestone with minor mineralization. Mineralized Webb Fm. basal breccia (9 to 45 m thick) overprinted by tectonic breccia (Doxey and others (2005). The breccia contains ≤25% barite as clasts and cement.

References

Doxey, K., Essman, J., Harris, D., Masterman, S., and Nemitz, M., 2005, Geology and mineralization of the Emigrant deposit, Elko County, Nevada, in Sediment-hosted gold deposits of the southern Carlin Trend, northeast Nevada: Reno, Geological Society of Nevada Symposium 2005, Field Trip Guidebook 6, p. 115–136.
Jackson, P.R., 1991, Geology and mineralization at the Emigrant Springs project, Elko County, Nevada, in Buffa, R.H., and Coyner, A.R., eds., Geology and ore deposits of the Great Basin: Reno, Geological Society of Nevada, Field Trip Guidebook Compendium, v. 1, p. 125–130.
Longo, A.A., Thompson, T.B., and Harlan, J.B., 2002, Geologic overview of the Rain subdistrict, in Thompson, T.B., Teal, L., and Meeuwig, R.O., eds., Gold deposits of the Carlin trend: Nevada Bureau of Mines and Geology Bulletin 111, p. 168–189.
Newmont Mining Corp., 2009, Annual report 2009: Annual Report, p. 33, footnote (4), last accessed May 12, 2011, at http://www.newmont.com/interactive-annual/pdf/newmont-09annualreport.pdf.
Thoreson, R.F., 1991, Geology and gold deposits of the Rain subdistrict, Elko 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. 635–642.