Robinson Mine

Producer in White Pine county in Nevada, United States with commodities Gold, Copper, Molybdenum, Silver

Geologic information

Identification information

Deposit ID 10310402
MRDS ID W700594
Record type Deposit
Current site name Robinson Mine
Alternate or previous names Aultman Pit, Kimberly Pit, Liberty Pit, Ruth Pit, Tripp Pit, Veteran Pit, Wedge Pit, Veteran Extension, Twin Peaks, Puritan, Pilot Knob, Northwest Ruth, New Liberty, Nellie, Los Angeles, Kranovich, J. D. Hill, Alpha, Rob Roy, Robinson Gold

Comments on the site identification

  • This record includes information from earlier MRDS records W700594 and W031574 as well as many other individual mine records form the many properties that make up the Robinson mine property.

Geographic coordinates

Geographic coordinates: -114.99948, 39.25661 (WGS84)
Relative position The Robinson Mine area is located from about 1.5 mile west of Ely to about 6.5 miles west of Ely, Nevada, in the central part of the Egan Range.
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Geographic areas

Country State County
United States Nevada White Pine

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 016N 062E 07-18 Nevada
Mount Diablo 016N 063E 08, 09, 16-18 Nevada

Comments on the location information

  • The Robinson district mine workings are spread out in an east-west linear belt extending from about 1.5 mile west of Ely to about 6.5 miles west of Ely.

Commodities

Commodity Importance
Gold Primary
Copper Primary
Molybdenum Secondary
Silver Secondary

Comments on the commodity information

  • Ore Materials: chalcocite, chalcopyrite, molybdenite, copper oxides; chrysocolla, malachite, azurite, cuprite, native copper, bornite, sphalerite, galena, pyrite, magnetite chalcopyrite, argentite
  • Gangue Materials: pyrite, sericite, clay minerals, fluorite, quartz, garnet- diopside skarn, magnetite, limonite

Materials information

Materials Type of material
Chalcocite Ore
Chalcopyrite Ore
Molybdenite Ore
Chrysocolla Ore
Malachite Ore
Azurite Ore
Cuprite Ore
Copper Ore
Bornite Ore
Sphalerite Ore
Galena Ore
Pyrite Gangue
Chalcopyrite Gangue
Argentite Gangue
Pyrite Gangue
Sericite Gangue
Clay Gangue
Fluorite Gangue
Quartz Gangue
Magnetite Gangue
Limonite Gangue

Alteration

  • (Local) Most significant is the hydrothermal alteration from monzonite intrusion. The deposit generally follows the typical porphyry copper deposit model in the pattern of alteration and mineralization. Anhydrous skarn developed in sedimentary rocks adjacent to potassically altered quartz monzonite. Peripheral to this is a quartz-sericite alteration zone followed by a quartz-clay-pyrite zone. Lacally present are advanced argillic alteration and some formation of retrograde hydrous skarn.
  • (Local) potassic, quartz-sericite, quartz-clay-pyrite, argillic

Mineral occurrence model information

Model code 78
USGS model code 20c
Deposit model name Porphyry Cu-Au
Mark3 model number 34
Model code 58
USGS model code 18a
Deposit model name Porphyry Cu, skarn-related
Mark3 model number 9

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
    Rock unit name Ely Limestone
    Stratigraphic age (youngest) Early Permian
    Stratigraphic age (oldest) Late Mississippian
  • Host or associated Host
    Rock type Plutonic Rock > Porphyry
    Rock type qualifier altered quartz monzonite
    Stratigraphic age (youngest) Cretaceous
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Rock type qualifier altered porphyry
    Stratigraphic age (youngest) Cretaceous
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Siltstone
    Rock type qualifier impure
    Rock unit name Chainman Shale
    Stratigraphic age (youngest) Late Mississippian
    Stratigraphic age (oldest) Early Mississippian
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
    Rock type qualifier impure
    Rock unit name Chainman Shale
    Stratigraphic age (youngest) Late Mississippian
    Stratigraphic age (oldest) Early Mississippian
  • Host or associated Associated
    Rock type Plutonic Rock > Porphyry
    Rock type qualifier quartz monzonite
    Rock unit name Weary Flat quartz monzonite
    Stratigraphic age (youngest) Oligocene
    Stratigraphic age (oldest) Eocene
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Rock type qualifier porphyry
    Rock unit name Weary Flat quartz monzonite
    Stratigraphic age (youngest) Oligocene
    Stratigraphic age (oldest) Eocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock type qualifier dikes and flows

Nearby scientific data

(1) -114.99948, 39.25661

Geologic structures

Type Description Terms
Local Host rocks have been folded, faulted, and fractured. Mineralization follows fractures in some cases.
Regional Rocks in the are folded into na east-trending anticline with moderate to gentle dipping flanks, later intruded by pluton and cut by nomal faults.
Local Host rocks have been folded, faulted, and fractured.
Regional east-trending anticline with moderate to gentle dipping flanks

Ore body information

  • General form variable from tabular to blanket to disseminated

Controls for ore emplacement

  • The main influence on mineralizationi s the metamorphic aureole surrounding the porphyry intrusion, but mineralization also follows fractures in some cases.
  • local fractures and alteration:

Comments on the geologic information

  • In mid-Cretaceous time, Paleozoic miogeosynclinal sedimentary rocks were deformed into an overturned E-W-trending anticline whose upper limb was thrust to the southwest. The axis if the anticline was subsequently intruded by a composite quartz monzonite stock dated at 110 million years. Hydrothermal alteration and mineralization associated with emplacement of the pluton formed the Ruth porphyry copper-gold system. Basin-and-Range normal faulting successively down-dropped the upper portions of the system to the east. A post-ore rhyolite intrusive cut the system 30 million years ago.

Economic information

Economic information about the deposit and operations

Operation type Surface-Underground
Development status Producer
Deposit size Large
Significant Yes
Discovery year 1868
Discoverer Thomas Robinson (1868)
Mining method Open Pit
Year of first production >1860
Year of last production 2009
Production years Late 1800's-1978, 1986-1999, 2005-present
Milling method Flotation

Mining district

District name Robinson District

Land status

Ownership category Private
Area name Ely BLM Administrative area

Ownership information

  • Type Owner-Operator
    Owner Quadra Mining Limited
    Home office Suite 2414, Four Bentall Centre 1055 Dunsmuir Street, P.O. Box 49185 Vancouver, BC, Canada
    Year 2004
    First year 2003
  • Type Owner-Operator
    Owner Nevada Mines Divison of Kennecott Copper Coporation
    Year 2004
    First year 1958
    Last year 1978
  • Type Owner-Operator
    Owner Magma Copper Company
    Year 2004
    First year 1990
    Last year 1997
  • Type Owner-Operator
    Owner BHP Ltd.
    Year 2004
    First year 1997
    Last year 2003

Production statistics

  • Year 1996
    Material Metal contained in concentrates. Major Mines of Nevada 1996. http://minerals.state.nv.us/forms/mining/MajorMinesOfNevada/mm1996.pdf
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 1,200,000g
    Primary Copper Copper 38,000mt
    Secondary Silver Silver 5,300,000g
  • Year 1997
    Material Metal in concentrates. Nevada Major Mines of 1997. http://www.nbmg.unr.edu/Pubs/mm/p9/mm97.htm
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 2,200,000g
    Primary Copper Copper 62,600mt
    Secondary Silver Silver 9,770,000g
  • Year 1998
    Material Metal in concentrates. Major Mines of Nevada 1998. http://www.nbmg.unr.edu/dox/mm/mm98.pdf
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 2,700,000g
    Primary Copper Copper 67,352mt
    Secondary Silver Silver 9,315,000g
  • Year 1999
    Material Metal in concentrates. Major Mines of Nevada 1999. http://www.nbmg.unr.edu/dox/mm/mm99.pdf
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 816,470g
    Primary Copper Copper 28,012mt
    Secondary Silver Silver 4,762,070g
  • Year 2004
    Material Quadra NR 22_Feb_2005.
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 326,280g 0g/mt
    Primary Copper Copper 10,700mt 1wt-pct
  • Year 2005
    Material Ore milled. Quadra NR 09_Jan_2006. Quadra NR 10_Mar_2006.
    Ore mined 13,748,000mt
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 2,517,500g 0g/mt
    Primary Copper Copper 57,240mt 1wt-pct
  • Year 2006
    Material Ore milled. 15,281,000 mt ore mined. Quadra NR 15_Jan_2007.
    Ore mined 13,860,000mt
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 2,335,100g 0g/mt
    Primary Copper Copper 55,070mt 1wt-pct
  • Year 2007
    Material Ore milled. Quadra NR 19_Jan_2009.
    Ore mined 14,171,000mt
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 3,362,880g 0g/mt
    Primary Copper Copper 59,830mt 1wt-pct
  • Year 2008
    Material Ore milled. Quadra NR 19_Jan_2009.
    Ore mined 13,842,000mt
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 4,280,710g 0g/mt
    Primary Copper Copper 72,600mt 1wt-pct
  • Year 2009
    Material Ore milled. Quadra NR 11_Jan_2010.
    Ore mined 13,549,000mt
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 3,078,300g 0g/mt
    Primary Copper Copper 55,570mt 1wt-pct
  • Year 2010
    Material Quadra NR 24_Jan_2011
    Accuracy Accurate
    Best? Y
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Gold Gold 2,300,000g
    Primary Copper Copper 49,400mt

Reserves and resources

  • Type In-situ
    Estimate year 1993
    Reserves 1,911,148
    Total resources 201,384,000
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.11 g/mt Gold Primary 1993
    Copper Cu 0.605 wt-pct Copper Primary 1993
  • Type In-situ
    Estimate year 1997
    Proved 213,000,000mt ore
    Probable 7,000,000mt ore
    Total resources 220,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.26 g/mt Gold Primary 1997
    Copper Cu 0.55 wt-pct Copper Primary 1997
  • Type In-situ
    Estimate year 1998
    Proved 217,000,000
    Probable 9,000,000
    Total resources 226,000,000
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.23 g/mt Gold Primary 1998
    Copper Cu 0.54 wt-pct Copper Primary 1998
  • Type In-situ
    Estimate year 1999
    Proved 168,000,000
    Probable 8,000,000
    Total resources 176,000,000
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.26 g/mt Gold Primary 1999
    Copper Cu 0.59 wt-pct Copper Primary 1999
  • Type In-situ
    Estimate year 2004
    Reserves 146,300,000mt ore
    Remarks Used 0.10 (%Cu) Cut Off
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.13 g/mt Gold Primary 2004
    Copper Cu 0.678 wt-pct Copper Primary 2004
  • Type In-situ
    Estimate year 2004
    Proved 128,433mt ore
    Probable 4,282mt ore
    Total resources 132,714mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 0.285 g/mt Gold Primary 2004
    Copper Cu 0.687 wt-pct Copper Primary 2004
  • Type In-situ
    Estimate year 2006
    Reserves 145,516,000mt ore
    Remarks Quadra 20_Jan_2006 NR
    Commodity Subtype Grade units Group Importance Year
    Gold 0.249 g/mt Gold Primary 2006
    Copper 0.69 wt-pct Copper Primary 2006
  • Type In-situ
    Estimate year 2007
    Reserves 103,788,000mt ore
    Remarks Quadra 2007 AIF p. 15.
    Commodity Subtype Grade units Group Importance Year
    Gold 0.23 g/mt Gold Primary 2007
    Copper 0.68 wt-pct Copper Primary 2007
  • Type In-situ
    Estimate year 2009
    Reserves 121,693,000mt ore
    Remarks Quadra NR 20_Feb_2009
    Commodity Subtype Grade units Group Importance Year
    Gold 0.23 g/mt Gold Primary 2009
    Copper 0.54 wt-pct Copper Primary 2009

Comments on the reserve resource information

  • Quadra Robinson property, expected mine life - 2016 (2017 with stockpile processing). Quadra website accessed on 3/1/2011. http://www.quadrafnx.com/s/RobinsonMine.asp

Comments on the workings information

  • The mine area has been developed by many large open pits, several of which have merged and have obliterated many of the early underground workings. The resulting pit is one of the largest in the world; in 1998, the copper pit measured 2 miles long, 1 mile wide and 1000 feet deep.

Comments on other economic factors

  • Robinson is considered by the USGS to be one of the ?Giant Porphyry-Related Metal Camps of the World. By 1978, when the large porphyry copper mines closed, the Robinson mine area deposits had produced nearly 360 million tons of 1% copper ore, which included 2.7 million ounces of byproduct gold. In 1994, the geologic resource of the deposit was reported as 252 million tons of ore grading 0.553% Cu, 0.0102 opt Au. In 1996, the reserves of the deposit were reported as 264 million tons of ore grading 0.55% Cu and 0.316 opt Au. In 1999 reserves were reported as 194 million tons of ore grading 0.59% Cu and 0.007 opt Au proven and probable. The Robinson mine produced 61.8 million pounds of copper concentrate in 1999, along with 26,250 ounces of gold and 153,104 ounces of silver, the last year of production. In 2004, Quadra Mining Ltd. announced updated proven and probable reserves at its Robinson Mine total 146.3 million tons grading 0.687% Cu and 0.008 opt Au. Over 97% of the mineral reserves at the mine are in the proven category. Contained and recoverable copper at the Robinson Mine has increased from 1.67 and 1.38 billion pounds to 2.0 and 1.67 billion pounds respectively. The increased reserves add 2 years to the estimated 8 year mine life. Quadra began commercial production at Robinson on October 1, 2004, and produced 23.6 million pounds of copper and 10,490 ounces of gold in concentrate in the remainder of 2004. In 2006, proven and probable reserves were reported as 160,067,000 tons grading 0.69% copper and 0.007 ounces of gold per ton.

Comments on development

  • Gold and silver were first discovered in the area by Thomas Robinson in 1867-1868, who gave his name to the district. Other nearby gold properties were soon claimed and worked sporadically ubtil the end of the19th century. Copper was discovered here in the early 1870s, but insufficient demand, lack of transportation, low grade of the ore, and the difficulty in extracting the copper made it unprofitable to mine it. The abundance of low-grade copper ore interfered with the extraction of the gold and silver using the processes common at that time. In 1897, Charles D. Lane, from California , purchased the Chainman Mine and Mill on the hillside west of Mineral City. The town name was changed to Lane City and Lane spent $168,000 in the next two years on a water ditch, power plant, and cyanide plant to treat the oxide copper ore, but failed. An Eastern company bought the property and erected a second cyanide plant near the first one, but sulfide ore was encountered at 180 feet deep and the cyanide processes were ineffective on the sulfide ore; the mine shut down after just a few months of operations. The Chainman Mine properties then purchased by the Nevada Consolidated Copper Company but litigation stymied operations. On the opposite side of the canyon closer to Ely, the Ely Mining and Milling Company bought the Robinson Group and built a cyanide plant near the mine. Sulfides at a shallow depth caused that mill to shut down too. In 1900, Mark Requa, the son of a Comstock engineer, optioned the copper claims of Edwin Gray and Dave Bartley. His initial interest in the area was to build a feeder railroad to the Eureka and Palisade Railroad. However, the copper soon interested him and he organized the White Pine Copper Company in 1902, and soon solved problems related to metal extraction and transportation. About the same time, Thomas Kearns, David Keith and others organized the McDonald - Ely Company with D. C. McDonald as manager. The Giroux, Ely Mines, Chainman, Ely Central & Butte and Ely Mine companies merged with the White Pine Copper Company financed by Mark L. Requa and this organization became the Consolidated Copper Company, which prepared to build a smelter at McGill that would have a capacity to process 10,000 tons of ore a day. The Consolidated Copper Company led by Requa brought the Nevada Northern Railroad a distance of 150 miles from Cobre (near current Interstate 80) to Ely to transport the copper ore. On September 30, 1906, Mark Requa drove a copper spike made from Ruth Mine copper ore into the ground to celebrate the arrival of the train. With new management, cheap transportation, and more effective extraction processes, the copper deposits of Robinson were finally developed productively, and by 1907, when the smelter in nearby McGill was completed, thirty mining companies were in operation in the Robinson District. The first blister copper was shipped in 1908. The mine earned only $622,470 in the first year, but produced $6,561,787 worth of copper in 1909. Over the years, the Consolidated Copper Company developed the Richards, Alpha, Emma and Morris underground mines and employed about 1,200 men from World War I through the 1920s. Copper prices dropped to 5 cents per pound in 1932 initiating a decline that resulted in the closure of the Kimberly mines until January 1937. By 1941 there were again more than 1,000 men on the payroll and the skip was surfacing 9,000 tons of ore a day. The underground mines shut down in 1949 and by 1951 were converted into open pit mines. In 1958, Kennecott bought out Consolidated Copper Company's Robinson District copper mines, and the Kennecott Copper Company operated until declining copper prices forced closure in 1978. In that time, more than 4.5 billion pounds of copper were taken from the Robinson District. At that time, ore production capa
  • After Kennecott shut down its copper operations in White Pine County, several other mining companies became interested in the Robinson district mines, more for their gold potential than for copper. Alta Gold and Magma Copper operated in the Robinson District from 1995 to 1996 and BHP operated from 1996 until 1999. Due to low copper and gold prices, BHP announced the closure of all of their North American holdings and laid off 462 employees in 1999. In 2004, the mine was acquired by Quadra Mining Ltd. who is reopening the mine (2004) to produce copper and gold. Quadra Mining Ltd. announced updated proven and probable reserves at its Robinson Mine total 146.3 million tons grading 0.687% Cu and 0.008 opt Au. Over 97% of the mineral reserves at the mine are in the proven category. Contained and recoverable copper at the Robinson Mine has increased from 1.67 and 1.38 billion pounds to 2.0 and 1.67 billion pounds respectively. The increased reserves add 2 years to the estimated 8 year mine life. Quadra began commercial production at Robinson on October 1, 2004, and produced 23.6 million pounds of copper and 10,490 ounces of gold in concentrate in the remainder of 2004.

Reference information

Bibliographic references

  • Age

    McDowell, F.W., and Kulp, J.L., 1967, Age of intrusion and ore deposition in the Robinson mining district of Nevada: Economic Geology, v. 62, p. 905?909

  • Deposit

    The Geological Society of Nevada 1996 Spring Field trip, Geology and Gold Deposits of Eastern Nevada, GSN Special Publication No. 23.

  • Geology

    Westra, G., 1982, Alteration and mineralization in the Ruth porphyry copper deposit near Ely, Nevada, Economic Geology; v. 77; no. 4; p. 950-970

  • Ownership

    http://www.quadramining.com/i/pdf/RobinsonNI43-101Final.pdf

  • Production

    Production Results from Quadra Mining Ltd. http://www.quadramining.com/s/RobinsonMine.asp

  • Reserve-Resource

    http://www.quadramining.com/i/pdf/RobinsonNI43-101Final.pdf, pg 68

  • Deposit

    Wilson, W. R., 1978, Geology of the Robinson Mining District, Nevada, Nevada Bureau of Mines and Geology Report 32, pp. 55 - 61.

  • Geology

    Bauer, H.L., Jr., Breitrick, R.A., Cooper, J.J., and Anderson, J.A., 1966, Porphyry copper deposits in the Robinson mining district, Nevada, in Titley, S.R., and Hicks, C.L., eds., Geology of the porphyry copper deposits, southwestern North America: Univ. of AZ Press, Tucson, AZ

  • Reserve-Resource

    Revised Reserve Table as of Janurary 1, 2006 http://www.quadramining.com/i/pdf/2006-01-20_NR.pdf

  • Deposit

    Spencer, A. C., 1917, The Geology and Ore Deposits of Ely, Nevada, USGS Professional Paper 96, 189 pp.

  • Geology

    Einaudi, M.T., 1982, Description of skarns associated with porphyry copper plutons, in Titley, S.R., ed., Advances in geology of the porphyry copper deposits, southwestern North America: Tucson, University of Arizona Press, p. 139-183.

  • Deposit

    Mining Magazine, January 1989, p. 44.

  • Geology

    James, L.P., 1976b, Zoned alteration in limestone at porphyry copper deposits, Ely, Nevada: Economic Geology, v. 71, p. 488?512.

  • 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.

  • Geology

    James, L.P., 1990, Gold in the Ely (Robinson) copper district, White Pine County, Nevada: U.S. Geological Survey Bulletin 1857?E, p. E28?E42.

  • Deposit

    Durgin, Dana, 1989, Alta Gold's Robinson Project, in GSN Special Pub. #9, Geology and Mineral Deposits of White Pine County, 1989 Spring Field Trip Guide Book, eds. Schafer and Buffa.

  • Geology

    Maher, David, 1996, Stratigraphy, structure, and alteration of igneous and carbonate wall rocks at Veteran Extension in the Robinson (Ely) porphyry copper district, Nevada, in Coyner, A.R., and Fahey, P.L., eds., Geology and ore deposits of the American Cordillian

  • Deposit

    Felix E. Mutschler, Steve Ludington, and Arthur A. Bookstrom, 1999, Giant Porphyry-Related Metal Camps of the World-A Database; USGS Open-File Report 99-556.

  • Geology

    Seedorff, E., 1993, Robinson mining district geology and mineralization, summer field trip: Geological Society of Nevada Special Publication 17, 69 p.

  • Deposit

    Quadra Mining Ltd. news releases, 8/11/2004, 2/22/2005.

  • Geology

    Shaver, S.A., and Jeanne, R.A., 1996, The geology and evolution of the weakly Au-(Cu)-mineralized far eastern side of the Robinson mining district, Ely, Nevada, in Coyner, A.R., and Fahey, P.L., eds., Geology and ore deposits of the American Cordillera

  • Deposit

    NBMG MI-2004.

  • Geology

    Westra, G., 1979b, Porphyry copper genesis at Ely, Nevada, in Ridge, J.D., ed., Papers on mineral deposits of Western North America, The International association on the genesis of ore Deposits, Fifth Quadrennial Symposium Proceedings, v.2: Nevada Bureau of Mines

  • Deposit

    http://www.quadramining.com/s/RobinsonMine.asp

General comments

Subject category Comment text
Deposit The Ely (Robinson) porphyry Cu-(Au-Mo) deposit, Cu-and Fe-skarns, and precious metaldeposits were once part of a contiguous mineralized system of Cretaceous age that was cut up and rotated by Tertiary Basin and Range-type normal faulting. The Robinson deposit generally follows the typical porphyry copper deposit model in the pattern of alteration and mineralization. associated with emplacement of a quartz monzonite pluton. Additional oreodies formed in adjacent sedimentary rocks. Silty to sandy layers of the Chainman Shale provided initial permeability, enhanced by later faulting. At the Ada, Rob Roy, and Los Angeles deposits, ore formation occurred in a favorable zone bounded by massive Ely Limestone and impermeable Chainman black shales. These ore horizons are oxidized stratabound blankets of silica-clay-pyrite-rich material.
General *****SEE related Deposit-Star Pointer Gold Mine- Deposit ID 10310382 Ruth Mine- Deposit ID 10080427

Reporter information

Type Date Name Affiliation Comment
Reporter 01-DEC-2004 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.