Ann Mason

Porphyry copper deposit in Nevada, United States

Names and other identifiers

GMRAP ID 46
Tract name Western U.S. and Sonoran Desert Jurassic Arc (003pCu9006x)
Site status deposit

Geographic location

Country United States
State or province Nevada
Geographic location -119.27, 38.96
Geologic map unit -119.27, 38.96
Nearby data

Geologic information

Deposit type Porphyry copper
Age (Ma) 169Ma
Age determination method unknown
Age range 169 Ma
Age reference Singer and others (2008)
Minerals actinolite, albite, biotite, bornite, chalcopyrite, chlorite, epidote, hematite, magnetite, molybdenite, pyrite, rutile, sericite, tourmaline
Associated rocks andesite dike, granite porphyry, rhyolite dike, andesite, argillite, gypsum, ignimbrite, rhyolite, sandstone, volcaniclastic rocks, breccia, dolomite, granite, limestone, quartz monzodiorite, quartz monzonite, skarn
Tectonic setting mixed
Stratigraphic age Middle Jurassic

Commodity and development information

Development status Prospect
Major commodities Cu, Mo
Tonnage (Mt) 2,250Mt
Cu grade (%) 0.29%
Mo grade (%) 0.005%
Au grade (g/t) 0.025g/t
Ag grade (g/t) 0.58g/t
Contained copper 3,800,000t
Gold-Moly ratio 5

Reference information

Comments Resource update as of August 2012: indicated + inferred resources at 0.15% Cu cutoff (lowest reported) for Ann Mason, not including neaby Blue Hill mixed oxide/sulfide ore (72.13 Mt at 0.17% Cu).
Study area name United States
References Albino (1995); Dilles and Einaudi (1992); Dilles and Proffett (1995); Entrée Gold Inc. (2013); Giralia Resources (2004); Pacific Magnesium Corp. Ltd. (2006); Watkins and others (2012); Singer and others (2008); Singer and others (2005)
Site reference U.S. Geological Survey National Mineral Resource Assessment Team (2002)
Albino, G.V., 1995, Porphyry copper deposits of the Great Basin—Nevada, Utah, and adjacent California, in Pierce, F.W., and Bolm, J.G., eds, Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest 20, p. 267–296.
Dilles, J.H., and Einaudi, M.T., 1992, Wall-rock alteration and hydrothermal flow paths about the Ann-Mason porphyry copper deposit, Nevada—A 6-km vertical reconstruction: Economic Geology, v. 87, p. 1963–2001. (Also available at http://dx.doi.org/10.2113/gsecongeo.87.8.1963.)
Dilles, J.H., and Proffett, J.M., 1995, Metallogenesis of the Yerington batholith, Nevada, in Pierce, F.W., and Bolm, J.G., eds., Porphyry copper deposits of the American Cordillera: Tucson, Arizona Geological Society Digest 20, p. 306–315.
Entrée Gold Inc., 2013, Projects: Entrée Gold Inc. Web page accessed September 25, 2013, at http://www.entreegold.com/projects/.
Giralia Resources NL, 2004, AGM Presentation, 25 November, 2004: Giralia Resources NL presentation 26 p., accessed [date unknown] at http://www.giralia.com.au/pdf/asx/AGMPresentationNov%202004.pdf. [Web page no longer available.]
Pacific Magnesium Corp. Ltd., 2006, Ann Mason copper deposit—New results: Pacific Magnesium Corp. Ltd. press release, June 1, 2006, 4 p., accessed February 6, 2014, at http://www.pacmag.com.au/aurora/assets/user_content/File/010606annmasonresults.pdf.Singer, D.A., Berger, V.I., and Moring, B.C., 2005, Porphyry copper deposits of the world—Database, map, and grade and tonnage models: U.S. Geological Survey Open-file Report 2005-1060, [9] p. and digital data, accessed December 31, 2013, at http://pubs.usgs.gov/of/2005/1060/.Singer, D.A., Berger, V.I., and Moring, B.C., 2008, Porphyry copper deposits of the world—Database and grade and tonnage models, 2008: U.S. Geological Survey Open-File Report 2008-1155, [45] p. and digital data, accessed December 31, 2013, at http://pubs.usgs.gov/of/2008/1155/.Watkins, Thomas; Page, Norman; Gant, Jonathan; and Limbach, Fred, 2012, An update on the Ann Mason copper-molybdenum porphyry, Lyon County, NV: Entrée Gold Inc. presentation, 29 p., accessed February 27, 2014, at http://www.entreegold.com/_resources/Watkins_NWMA_7Dec2012_Final_2.pdf.