1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Rochester

Producer in Pershing county in Nevada, United States with commodities Silver, Gold, Lead, Zinc, Copper, Antimony
Map
XML
JSON
KML
A
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Land status
  18. Ownership information
  19. Reserves and resources
  20. Links to other databases
  21. Bibliographic references
  22. General comments
  23. Reporter information

Geologic information

Identification information

Deposit ID 10042547
MRDS ID M060371
Record type Site
Current site name Rochester
Alternate or previous names Coeur Rochester, Nenzel Hill, NBMG Sample Site 2645
Related records 10150157, 10247172, 10310354

Geographic coordinates

Geographic coordinates: -118.14153, 40.29073 (WGS84)
Elevation 2195
Relative position 26 MILES NE OF LOVELOCK, ON NENZEL HILL

Site location context

Political divisions (FIPS codes)

Pershing(county)

Nevada(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Rochester(quadrangle 1:24,000 scale)

Lovelock(quadrangle 1:100,000 scale)

Lovelock(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Dixie Valley(hydrologic unit)

Central Nevada Desert Basins(hydrologic accounting unit)

Central Nevada Desert Basins(hydrologic subregion)

Great Basin(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management NV)

Bureau of Land Management NV BLM(Type of land area)

BLM(Federal land areas administered by BLM)

Geographic areas

Country State County
United States Nevada Pershing

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 028N 034E ALL Nevada

Comments on the location information

  • LOCATION IS TO ADMINISTRATIVE BUILDING AT MINE SITE. LATITUDE AND LONGITUDE PROVIDED BY KURT CATO, MINE GEOLOGIST

Commodities

Commodity Importance
Silver Primary
Gold Primary
Lead Secondary
Zinc Critical Secondary
Copper Secondary
Antimony Critical Secondary

Comments on the commodity information

  • SEE VIKRE (1981, FIG 6) FOR PARAGENETIC SEQUENCE. GOLD AND SILVER ARE STRONGLY ZONED. AG-RICH CORE (FOLLOWING NE STRUCTURES) WITH PERIPHERAL AU HALO. AU SHOWS STRONGER AFFINITY FOR ROCHESTER/WEAVER CONTACT. QUARTZ IS THE MOST COMMON HOST MINERAL. UNOXIDIZED BLOCKS OF ORE ARE FOUND THROUGHOUT THE DEPOSIT AND DRILLING HAS SHOWN OXIDATION CONTINUING TO AT LEAST 1,000 FT. BELOW NENZEL HILL.

Materials information

Materials Type of material
Acanthite Ore
Anglesite Ore
Argentite Ore
Chalcanthite Ore
Chalcocite Ore
Chalcopyrite Ore
Chlorargyrite Ore
Covellite Ore
Electrum Ore
Embolite Ore
Galena Ore
Melanterite Ore
Owyheeite Ore
Polybasite Ore
Pyrargyrite Ore
Pyrite Ore
Pyrrhotite Ore
Silver Ore
Sphalerite Ore
Stromeyerite Ore
Goethite Gangue
Hematite Gangue
Limonite Gangue
Quartz Gangue
Sericite Gangue

Alteration

  • (Local) Silicification, Oxidation

Analytical data

Result 1: 800-1000 PPM PB
Result 500-700 PPM ZN
Result 80-100 PPM CU
Result 200-300 PPM AS
Result APPROX. 50 PPM SB 2: 1% FE
Result 0.025 MG
Result 0.005% TI
Result 1500 PPM AS
Result 0.65 PPM AU (BY AA ANALYSIS)
Result 20 PPM B
Result 70 PPM BA
Result 1.5 PPM BE
Result 100 PPM CU
Result 2000 PPM PB
Result 100 PPM SB
Result 10 PPM V
Result 200 PPM ZN

Mineral occurrence model information

Model code 273
USGS model code 36a
Deposit model name Low-sulfide Au-quartz vein
Mark3 model number 27

Host and associated rocks

  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic)
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Volcanic Breccia (Agglomerate)
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock unit name Rochester Rhyolite, Koipato Group;Weaver Formation, Koipato Group
    Rock description Rochester Rhyolite, Koipato Group;Weaver Formation, Koipato Group

Nearby scientific data

(1) Alluvium, undifferentiated
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Broad, Asymmetrical Anticlinal Arch
Type of structure Local
Structure description 2 Major Normal Fault Systems; Post Mineral Faults

Ore body information

  • Name WEAVER/ROCHESTER CONTACT
    Strike }N10W-N10E}N30-60W
    Dip }30-70W}40-70W
    Thickness 548.64M
    Length 457.2M
    Width 1.83M
    Depth to top 0M
    Depth to bottom 304.8M
  • Name EAST VEIN SET
    Strike }N10W-N10E}N30-60W
    Dip }30-70W}40-70W
    Thickness 304.8M
    Length 487.68M
    Width 457.2M
    Depth to top 0M
    Depth to bottom 304.8M
  • Name WEST VEIN SET
    Dip }30-70W}40-70W

Controls for ore emplacement

  • High Angle Faults

Comments on the geologic information

  • REGIONAL QUARTZ-SERICITE-PYRITE ALTERATION IS BELIEVED TO BE ASSOCIATED WITH EMPLACEMENT OF STOCKS, PARTICULARLY THOSE IN WESTERN PERSHING COUNTY. THE REGIONAL ANTICLINE TRENDS NNW WITH THE AXIAL PLANE DIPPING W. BEDDING DIPS SHALLOWLY E, AS INDICATED BY EPICLASTIC WEAVER UNITS. BOTHE WEAVER AND ROCHESTER FORMATIONS ARE PARTS OF THE PERMIAN-TRIASSIC KIOPATO GROUP. "QUARTZ-SERICITE-PYRITE ALTERATION IS ASSOCIATED WITH MINERALIZED QUARTZ VEINS [IN THE DEPOSIT] AND IS DIFFICULT TO DISTINGUISH FROM THE REGIONAL-TYPE HYDROTHERMAL ALTERATION," (STRUSACKER). "AU, AG, SB, AS, HG, AND S CONCENTRATIONS IN MINERALIZED WEAVER RHYOLITE INCREASE SHARPLY WITH DEGREE OF ALTERATION" (VIKRE, 1981) K/AR DATES OF THE DEPOSIT RANGE FROM 85 TO 114 MY, AVERAGING 99 MY. AT LEAST 3 TRENDS OF POST-MINERAL MOVEMENT HAVE BEEN NOTED: (1) E-W, DIPPING STEEPLY N OR S; (2) N30W-N50W, DIPPING 30-70W; (3) N20W-N20E, 70-80E (LATE MIOCENE BASIN AND RANGE?)

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Large
Significant No
Discovery year 1905
Discoverer John Nenzel
Year of first production 1912
Year of last production 1993
Production years 1912-1928; 1986-PRESENT

Mining district

District name Rochester

Land status

Ownership category
Area name Blm Winnemucca District

Ownership information

  • Type Owner-Operator
    Owner Coeur-Rochester Mines, Inc.
    Home office P.O. Box 1057, Lovelock, Nv 89419

Comments on the production information

  • JOHNSON (1977, P.80) GIVES A YEAR BY YEAR PRODUCTION TABLE FOR 1912-1929, 1931-1951, 1953-1966. FIGURES FROM JOHNSON ARE FOR ENTIRE ROCHESTER DISTRICT, BUT MOST OF PRODUCTION CAME FROM ROCHESTER MINE (PRODUCTION FIGURES FOR PLACER AU NOT GIVEN HERE BECAUSE ROCHESTER MINE IS NOT A PLACER DEPOSIT). "HISTORICALLY, THE DISTRICT PRODUCED 8,769,000 OUNCES OF AG AND 81,343 OUNCES OF AU AND IS SECOND ONLY TO THE COMSTOCK DEPOSIT IN AG PRODUCTION," (STRUHSACKER, 1993).

Reserves and resources

  • Type In-situ
    Estimate year 1985
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 42.353 g/mt Silver Major 1985
    Gold Au 0.31 g/mt Gold Major 1985

Comments on the reserve resource information

  • 1985 TONNAGE ESTIMATES WERE INCREASED FROM 88 MILLION ST TO 112.5 MILLION ST AG-AU ORE BASED ON 1984 DRILLING PROGRAM WHICH WAS EXTENDED TO THE SOUTH WHERE THE MINERALIZATION REMAINED OPEN.

Comments on the workings information

  • 1986 TO PRESENT-OPEN PIT. EARLIER MINING ON EAST AND WEST VEINS CREATED 3 LONG TUNNELS: PITT, FRIEDMAN, AND CROWN POINT LEVELS, SHOWN IN FIG 5 OF VIKRE, 1981.

Comments on development

  • EARLY (1912 ) UNDERGROUND MINING OF THE DEPOSIT OCCURRED ON THE EAST AND WEST VEINS ON NW SIDE OF NENZEL HILL. BETWEEN 1912 AND 1913, ORE AVERAGING <35 OZ/TON COULD NOT BE PROFITABLY MINED DUE TO SHIPPING COSTS. BY 1915, ORE ASSAYING AS LOW AS 8 OZ/TON COULD BE EXTRACTED PROFITABLY DUE TO CONSTRUCTION OF A CYANIDE MILL AND THE NEVADA SHORT LINE RAILWAY. A 12,016 FT. TRAMWAY WAS BUILT IN 1917 TO HAUL ORE FROM THE FOOT OF NENZEL HILL TO THE MILL IN LOWER ROCHESTER CANYON. THE 72 BUCKETS EACH HELD 600 LBS OF ORE, REDUCING THE COST OF DELIVERING ORE TO THE MILL TO $0.17/TON. MAJOR PRODUCTION ENDED BY 1923, CAUSED BY GRADE AND PRICE FLUCTUATIONS AND BY LITIGATION. LIMITED MINING CONTINUED UNTIL 1928. OWNERSHIP/LEASEES: 1960-69 SILVER STATE MINING CO.; 1969-1984 ASARCO DRILLED 485 HOLES (160,000 FT.); 1983 COEUR D'ARLENE MINES PURCHASED PROPERTY. ; TOTAL$: >$44 MILLION ; ECON.COM: COEUR ROCHESTER IS AN OPEN PIT, HEAP LEACH MINE. RELATIVELY UNIFORM GRADES AND SIMPLE METALLURGY, MINIMAL
  • STRIPPING, AND DOWNHILL HAULAGE HELP KEEP PRODUCTION COSTS LOW. 1993 RECOVERY RATES AVERAGE 55% OF THE AG AND 80-85% OF THE AU IN HEAP LEACH PADS. IN 1993, THE MINE EMPLOYED ABOUT 290 PEOPLE. WEEKLY DORE PRODUCTION AVERAGES 100,000 TROY OZ (98% AG, 1% AU, 1% MISC. IMPURITIES). RELATIVELY UNIFORM GRADE AND SIMPLE METALLURGY, MINIMAL STRPPING, AND DOWNHILL HAULAGE HELP KEEP PRODUCTION COSTS LOW. 1993 CUT OFF GRADE IS 1.4 PER TON AG EQUIVALENT, WITH A STRIP RATIO OF 2.0:1. REMAINING MINE LIFE IS 10 YEARS IN 1993 (STRUHSACKER, 1993).

Reference information

Bibliographic references

  • Analytical Data

    1: ORAL PRESENTATION DURING ROCHESTER MINE TOUR, GSN, 25 SEPT/93 2: DATA FRO M NBMG SAMPLE 2645

  • Deposit

    STRUSACKER, E., (ED.), 1993, GOLD AND SILVER DEPOSITSF WESTERN NEVADA: GEOLOGICAL SOCIETY OF NEVADA SPECIAL PUBLICATION NO.18, 1993 FALL FIELD TRIP GUIDE

  • Deposit

    SCHRADER, F.C., 1914, THE ROCHESTER MINING DISTRICT, NEVADA: USGS BULLETIN 580-M

  • Deposit

    KNOPF, A., 1924, GEOLOGY AND ORE DEPOSITS OF THE ROCHESTER DISTRICT, NEVADA: USGS BULLETIN 762, PP.78-81

  • Deposit

    VIKRE, P.G., 1977, GEOLOGY AND SILVER MINERALIZATION OF THE ROCHESTER DISTRICT, PERSHING COUNTY, NEVADA: STANFORD UNIVERSITY, UNPUBLISHED PHD. DISSERTATION

  • Deposit

    VIKRE, P.G., 1981, SILVER MINERALIZATION OF THE ROCHESTER DISTRICT, PERSHING COUNTY, NEVADA: ECONOMIC GEOLOGY, V.76, PP 580-609

  • Deposit

    JOHNSON, M.G., 1977, GEOLOGY AND MINERAL DEPOSITS OF PERSHING COUNTY, NEVADA: NBMG BULLETIN 89, PP.78-80

  • Deposit

    BONHAM, H.F. AND HESS, R.H., 1993, IN, THE NEVADA MINERAL INDUSTRY-1992: NBMG SPECIAL PUBLICATION MI-1992, P26

  • Deposit

    TINGLEY, J.V., 1985, NENZEL HILL, NBMG SAMPLE 2645, PERSHING COUNTY, ROCHESTER DISTRICT; NBMG UNPUBLISHED MINING DISTRICT (TINGLEY) FILES

  • Deposit

    NEVADA BUREAU OF MINES AND GEOLOGY, MINING DISTRICT FILES, VARIOUS CLIPPINGS, 1983-1985

  • Deposit

    MINSEARCH ANNUAL, 1984-1985, V. VII, PP 380-384; METALS ECONOMICS GROUP, BOULDER, CO

  • Deposit

    BONHAM, H.F., GARSIDE, L.J., JONES, R.B., PAPKE, K.G., QUADE, J., TINGLEY, J.V., 1985, A MINERAL INVENTORY OF THE PARADISE-DENIO AND SONOMA-GERLACH, WINNEMUCCA DISTRICT, NEVADA: NBMG OPEN FILE REPORT 85-5

  • Deposit

    NBMG, 1994, MI-1993

  • Deposit

    NEVADA DIVISION OF MINERALS, 1994

  • Production

    JOHNSON (1977, P.80); BONHAM AND HESS (1993, P.26) MI-1993

  • Reserve-Resource

    MI-1993

General comments

Subject category Comment text
Deposit SPACED AND OFTEN LAMINAR. N-S VEINS CUT E-W VEINS. TWO BROAD WEST VEIN ZONES AND AT LEAST 6 SEPARATE EAST VEIN SETS HAVE BEEN IDENTIFIED. INTESECTIONS OF THESE ZONES ARE EXCELLENT HOSTS. WHEN THE VEIN SET INTERSECTIONS CUT THE WEAVER/ROCHESTER CONTACT, ORE DEVELOPMENT IS FUTHER ENHANCED. DURING EARLY MINING (1912-1915), THE EAST AND WEST VEINS AVERAGED 6 FT. IN WIDTH AND CARRIED 12 OZ AG AND 0.100 OZ AU/TON. VEINS NARROWED (AND SOME DIPS FLATTENED) AND BECAME LOWER GRADE WITH DEPTH (VIKRE, 1981).; MODEL NAME COULD ALSO BE: COMSTOCK EPITHERMAL VEINS.
Deposit ROCHESTER DEPOSIT HAS SOME OF THE CHARACTERISTICS OF ADULARIA-SERICITE MODEL, BUT STUDIES BY VIKRE AND MINE STAFF SHOW THAT DEPOSIT WAS PROBABLY FORMED AT GREATER DEPTH (>12,000 FT?), TEMPERATURE (300-400C), AND PRESSURE (1KB) THAN ADULARIA-SERICITE MODEL . LOW VOLUME OF CLAYS. NO EVIDENCE OF BOILING. MESOTHERMAL DEPOSIT? VIKRE (1981) GENETICALLY LINKS RICHER VEINS (LIKE EAST AND WEST VEINS) WITH LOWER GRADE, HIGHER TONNAGE ORE, BUT REPORTS STRUCTURAL DIFFERENCES. ROCHESTER DEPOSIT IS OXIDIZED THROUGH TO ITS KNOWN BOTTOM. EAST AND WEST VEINS AVERAGE 8 OZ AG AND 0.1 OZ AU/TON; THE ENTIRE ROCHESTEREPOSIT AVERAGES 1.5 OZ AG AND 0.011 OZ AU/TON (1993). AU GRADE IS EXPECTED TO RISE TO 0.02-0.025 NEAR THE END OF THE MINE LIFE AS A HIGH-GRADE VEIN IS MINED NE AR THE PRESENT TERTIARY CRUSHER. MOST ROCHESTER ORE IS DISSEMINATED IN STOCKWORK AND SILICEOUS BRECCIA. HIGH-GRADE, FAULT-CONTROLLED VEINS PROVIDE SMALLER QUANTITY BUT RICHER ORE. VEINS ARE REPLACEMENT, TIGHT (FEW VUGS), CLOSELY

Reporter information

Type Date Name Affiliation Comment
Reporter 01-DEC-1979 Harner, Joy L. (Roberts, Ralph J.) U.S. Geological Survey
Updater 01-MAY-1986 La Pointe, D.D. Nevada Bureau of Mines and Geology
Updater 01-NOV-1993 Marcus, Susan U.S. Geological Survey
Updater 01-SEP-1994 Li, Zhiping (Moyer, Lorre A.) U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Current status (per MSHA)

StatusActive since 10/21/1985
MSHA mine ID2601941
Mine name (MSHA)Rochester Mine
Current operatorCoeur Rochester, Inc.
Current controller (parent)Coeur Mining, Inc.
Mine typeSurface (Metal / non-metal)

Inferred by coordinate + name similarity (1128 m, 1.00 match). Confirm against MSHA if precision matters — non-USGS-curated cross-references may occasionally point at a neighbouring mine.

Open MSHA's Mine Data Retrieval System for inspections, accidents, and violations for this mine.

External references

Maps centered on this site

Authoritative Nevada resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.