Twin Creeks Mine

Humboldt County, Nevada, United States

GoldSilverLeadZincArsenicMercuryAntimonyBarium-Barite

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Description

Gold Fields Mining Corp./ Santa Fe Pacific Gold

Commodities

PrimaryGold, Silver

TertiaryLead, Zinc, Arsenic, Mercury, Antimony, Barium-Barite

Commodity typeB

Deposit

Deposit typeSediment-hosted Au

Model173: Sediment-hosted Au

Deposit sizeL

Orebody formtabular to irregular

Ore controlThe "Rabbit Suture" is considered a first order control. The DZ fault was probably a feeder fault. Favorable calcareous lithologies within NW- trending overturned anticline are stratigraphic controls. Bedding in the lower member of the Etchart Limestone. Complex tectonics, stratigraphy and alteration.

Materials

Ore mineralsGold

GangueAlbite, Chlorite, Kaolinite, Sericite, Calcite, Amphibole, Quartz, Pyrite, Augite, Epidote, Limonite, Leucoxene, Feldspar, Tourmaline, Fluorite, Barite, Goethite

Geology

Host rockShale,Siltstone,Chert,Mafic Volcanic Rock,Limestone · "Valmy and Comus Formations", "Etchart Limestone"

Associated rockTuff,Basalt,Mixed Clastic/Volcanic Rock,Ultramafic Intrusive Rock

StructureThe Conelea overturned anticline dominates the structural picture of the early Rabbit Creek Mine area. The fold axis strikes N20-30W, dips 20-30 degrees southwest, and plunges 5 degrees northwest. The Conelea Anticline is offset by three NE-striking faults; the northernmost of the three (DZ fault) has about 2000 ft. of dextral offset. The DZ fault is interpreted as a Riedel "R" shear associated with an inferred major N-S basement suture with right lateral offset, the "Rabbit Suture". Low angle unconformity developed in the Gough's Canyon Formation. The Chimney Creek deposit occurs along a northeasterly range front lineament that is probably an extension of the Getchell Fault. Host rocks strike NE, dip 21-32 NW., Leviathan allochthon. Antler orogenic belt. major, deep seated, N-S structural zone (suture) 40 km (25 miles) long, known as the Getchell high-angle fault system bounds the eastern flank of the Osgood Mountains. N-S trending belt of gold mineralization that is at least 5.6 km (3.5 miles) long and 300 m (1000 ft) to 450m (1500ft) wide. Roberts Mountain Thrust (below) and the Golconda Thrust (above), intruded by the mid-Cretaceous Osgood Mt. granodiorite and related trachyandesite dikes.

Tectonic settingback-arc thrust belt

AlterationDecalcification, silicification, dolomitization, argillization, and minor sericitization of sediments. Albitization and propylitization of basalt. Decalcification increased porosity, allowing introduction of mineralizing fluids. Silica was introduced in several stages in the HGO orebody. Dolomitization accompanied one of the silicification stages. Argillization is important in the LGO orebody. Hydrothermal alteration formed sericite, kaolinite, dickite, alunite, natroalunite. A zone of phyllic alteration, 50 m wide around feeder zone, contains ore-grade mineralization. Carbonate dissolution zones; two generations of silicification (jasperoid); propylitic alteration of basalts.

Economic & production

Development statusProducer

Production years1987-present

First production1986

Last production2006

Discovery year1985

Identification

Deposit ID10310333

MRDS IDM242950

Alternate namesDZ Zone, Main, Chert Zone, HGO Zone, Jackrabbit Zone, LGO Zone, Sage, Section 8, Snowshoe Zone, South Layback, Section 30, South Oxide, Upper Sill Zone, West Pit, Chimney Creek Mine, Rabbit Creek Mine, Mega pit (the merged pit), SWS Zone

RegionNA

Data scoreA

Coordinates41.28322, -117.15096

References

Santa Fe Pacific Gold 1996 SEC Form 10KMining Engineering, 1/1/97Northern Miner, 2/6/95,Northern Miner, 6/3/96California Mining Journal, 3/1/95California Mining Journal, 3/1/96Pay Dirt, 2/1/96Pay Dirt, 3/1/96Pay Dirt, 11/1/96David P. Stenger, Stephen E. Kesler, Dean R. Peltonen, and Charles J. Tapper, 1998, Deposition of gold in Carlin-type deposits; the role of sulfidation and decarbonation at Twin Creeks, Nevada, Economic Geology; April 1998; v. 93; no. 2; p. 201-215.Bloomstein and others, 1991; Bonham, 1986, 1989, 1991; F. Breit, oral communication, 2000; Davis and Tingley, 1999; Gardiner, 1989, 1990Gardiner and Giancola, 1991Giancola, 1995, 1996, 1997, 1998, 1999, 2000Harding, 2004mMason and others, 1996;Nevada Bureau of Mines and Geology, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004; Newmont Mining Corp., 2003; Osterberg and Guilbert, 1991; Santa Fe Pacific Gold Corp., 1995a, 1995c; Schack, 2003; Tingley, 1998; United States Bureau of Land Management, 1979g, 1996e, 1996h; United States Bureau of Mines, 1995; United States Geological Survey, 1980d, 1980e.Nevada Mining Association Bulletin, Oct-Nov., 1985.The Mining Record, Nov. 13, 1985, P.3Reno Gazette Journal, Nov. 11, 1985.The Northen Miner Newspaper, Nov. 11, 1985.Mine Search Annual, 1984-85, Metals Economics Group, Boulder, Co, Vol vii, p. 93-94.Oral Communication from Jim Delong, 16 Jul. 1986, geologist formerly with Gold Fields.Geol. Soc. Nevada, 1987, Precious Metals Symposium, lectures, abstracts.E. I., Massengill, G.L. et. al., 1991, Discovery, geology and mineralization of the Rabbit Creek gold deposit, Humboldt Co., NV. Geology and Ore Deposits of the Great Basin, GSN Symposium Proceedings Reno, Nevada, p. 821-843.Madden-Mcguire, Dawn J., Smith, Steven M., et al., 1991, Nature and origin of alluvium above the Rabbit Creek gold deposit, Getchell Gold Belt, Humboldt Co., Nv. Geology and Ore Deposits of the Great Basin, GSN Symposium Proceedings Reno, Nevada,p. 895-911.Grauch,V.J.S., and Bankey, Viki, Preliminary results of aeromagnetic studies of the Getchell disseminated gold deposit trend, Osgood Mountains North Central Nevada. Geology and Ore Deposits of the Great Basin, GSN Symposium Proceedings Reno, Nevada, p. 781-791.California Mining Journal, April 1990The Humboldt Sun, Winnemucca, NV, July 27, 1990, p. 32 and 34.Rabbit Creek Mine, Santa Fe Pacific Ld Corp. brochure.The Nevada Mineral Industry, 1990, NBMG Spec. Pub. MI-1990.Willden, Ronald 1964, Geology and Mineral Deposits of Humboldt County, Nv: Nbmg Bull. 59p.NBMG, 1994, MI-1993Long, 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.