Nenzel Hill

Site Name

Primary: Nenzel Hill
Secondary: Silver State
Secondary: Rochester Canyon Tungsten
Secondary: Rochester
Secondary: Rochester Mines 0320270324
Secondary: Rochester Mine
Secondary: Coeur-Rochester
Secondary: Coeur-Rochester Open Pit
Secondary: Rochester Group Mine
Secondary: Rochester Merger Mines 0320270658
Secondary: Rochester Canyon Placer Gold

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Commodity

Primary: Silver
Secondary: Gold

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Location

State: Nevada
County: Pershing
District: Rochester

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Land Status

Land ownership: Mixed
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

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Holdings

Type: Other
Type: Patented
Type: Located Claim

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Workings

Type: Surface

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Ownership

Owner Name: Coeur D'Alene Mines Corp.
Percent: 100.0
Home Office: Idaho
Info Year: 1996
Years: 1983 -

Owner Name: Coeur-Precious Metals Co.
Home Office: Nevada
Info Year: 1996
Years: 1996 -

Owner Name: Royal Apex Silver Inc. (See Comments)
Percent: 100.0
Home Office: Idaho
Info Year: 1983

Owner Name: Asarco (American Smelting And Refining Co.)
Percent: 100.0
Info Year: 1996

Owner Name: Coeur-Rochester, Inc.
Home Office: Nevada
Info Year: 1995

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Production

Year: 1992
Description: Gold Produced 56562 Tr Oz/Yr
Year: 1992
Description: Silver Produced 5431369 Tr Oz/Yr
Year: 1993
Description: Ore Processed 6574869 Mt
Year: 1993
Description: Gold Produced 66412 Tr Oz/Yr
Year: 1993
Description: Silver Produced 5943894 Tr Oz/Yr
Year: 1991
Description: Ore Processed 6336085 Mt
Year: 1991
Description: Gold Produced 60565 Tr Oz/Yr
Year: 1991
Description: Silver Produced 5700000 Tr Oz/Yr
Year: 1992
Description: Ore Processed 6673556 Mt
Year: 1994
Description: Ore Processed 7039424 Mt
Year: 1994
Description: Gold Produced 56886 Tr Oz/Yr
Year: 1994
Description: Silver Produced 5937770 Tr Oz/Yr
Year: 1995
Description: Ore Processed 7478476 Mt
Year: 1995
Description: Gold Production 59307 Tr Oz/Yr
Year: 1995
Description: Silver Production 6481825 Tr Oz/Yr
Year: 1996
Description: Ore Processed 7375400 Mt
Year: 1996
Description: Gold Production 74293 Tr Oz/Yr
Year: 1996
Description: Silver Production 6251180 Tr Oz/Yr

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Deposit

Record Type: Site
Operation Category: Plant
Plant Type: Leach
Plant Subtype: Solvent Extraction-Electrowin
Operation Type: Surface
Mining Method: Open Pit
Milling Method: Leach-Solvent-Extract-Electrowin
Year First Production: 1905
Discovery Year: 1860
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: Y
Deposit Size: L

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Physiography

General Physiographic Area: Intermontane Plateaus
Physiographic Province: Basin And Range Province
Physiographic Section: Great Basin

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Mineral Deposit Model

Not available

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Orebody

Not available

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Structure

Not available

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Alterations

Not available

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Rocks

Not available

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Analytical Data

Not available

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Materials

Unknown: Acanthite
Unknown: Arsenopyrite
Unknown: Tetrahedrite
Unknown: Stromeyerite
Unknown: Sphalerite
Unknown: Sericite
Unknown: Quartz
Unknown: Pyrite
Unknown: Pyrargyrite
Unknown: Iron Oxides-Hydrated
Unknown: Electrum
Unknown: Chalcopyrite
Unknown: Cerargyrite
Unknown: Argentite
Unknown: Silver

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Comments

Comment (Reserve-Resource): GOLD ASSAY GRADE WAS NOT PUBLISHED. VALUES OF SILVER AND GOLD FROM ONE SOURCE DOCUMENT WERE REPORTED AS CONTAINING LOW-GRADE SILVER MINERALIZATION AND MINOR GOLD VALUES. REC 5 ALSO LISTED AS JAN. 1, 1995 (1996) PROVEN + PROBABLE RESERVES IN "R" REFERENCE 033. 1996 1OK: ESTIMATED RECOVERY RATES ARE 55% FOR AG AND 85% FOR AU.

Comment (Reserve-Resource): CAPACITY ESTIMATED FROM 1995 PRODUCTION OF 7,480,589 MT.

Comment (Workings): VALLEY FILL HEAP LEACH. CRUSH TO 1/2 AT 18,500 TPH, LEACH WITH 1.5 LB/TON SOLUTION USING DRIP LINE APPLICATION. AG AND AU ARE RECOVERED USING MERRILL-CROWE SYSTEM. PRESENT EMPLOYMENT IS 300.

Comment (Exploration): FROM 1969-82 ASARCO REPORTEDLY SPENT 2.9 MILLION DOLLARS IN EXPLORATION COSTS ON THE PROPERTY. WORK IN 1984 INCLUDED LARGE-SCALE HEAP LEACH TESTING AND ABOUT 1800 METER OF CORE DRILLING. IN 1984 DRILLING EXPANDED THE TOTAL MINERALIZED ZONE TO 102.1 MILLION MT. COEUR ENTERED INTO A 3-R LEASE OPTION AGREEMENT WITH THE RIGHT TO EXPLORE AND BUY THE ADJACENT NEVADA PACKARD PROPERTY, WHICH HAS A GEOLOGIC STRUCTURE VERY SIMILAR TO ROCHESTER. THE PROPERTY INCLUDES 35 CLAIMS AND ABOUT 1200 ACRES. A 22,000 FT DRILL PROGRAM SCHEDULED TO START 8/96. (PRESS RELEASE, 8/14/96)

Comment (Geology): GENERAL SIZE OF ORE BODY IS MEDIUM. THE ORE BODY STRIKES TO THE NE. THE THICKNESS VARIES FROM 0 TO +200 METERS. MINERAL ZONE DIMENSIONS REPRESENT DISSEMINATED AG GRADES OF MORE THAN 34 G/MT (1 OZ/T) AG. TOTAL AREA COVERED IS ABOUT 10,000 ACRES (4070 HTAC)

Comment (Geology): THE KOIPATO GROUP CONSISTS OF ROCKS FROM THE WEAVER ROCHESTER AND LIMERICK FORMATIONS WITH AGES FROM PERMIAN- TRIASSIC. LROCK 1101 IS A RHYOLITE TUFF.

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References

Reference (Deposit): NEVADA. NV BUREAU OF MINES AND GEOL. BULL 24, 1935, 73 PP.

Reference (Deposit): JOHNSON, M. G. GEOLOGY AND MINERAL DEPOSITS OF PERSHING

Reference (Deposit): COUNTY, NEVADA. NEVADA BUREAU OF MINES AND GEOLOGY

Reference (Deposit): BULLETIN 89, 1977, 115 PP.

Reference (Deposit): KOFP, A. GEOLOGY AND ORE DEPOSITS OF THE ROCHESTER

Reference (Deposit): DISTRICT, NEVADA. U.S. GEOL. SURV. BULL. 762, 1924,

Reference (Deposit): PP. 78.

Reference (Deposit): UPDATE 1980. NV BUREAU OF MINES AND GEOL. REP. 36, 1983,

Reference (Deposit): PP. 36-41.

Reference (Deposit): NEV. BUREAU OF MINES AND GEOLOGY SPECIAL PUBLICATION 10, 1990,

Reference (Deposit): P. 8.

Reference (Deposit): VIKRE, P. G. SILVER MINERALIZATION IN THE ROCHESTER DISTRICT

Reference (Deposit): PERSHING COUNTY, NEVADA, ECONOMIC GEOLOGY, V76, 1981, PP.

Reference (Deposit): 580 - 609.

Reference (Deposit): COEUR D'ALENE MINES CORPORATION, "ROCHESTER", FOLDER.

Reference (Deposit): RECONNAISSANCE OF MINING DISTRICTS IN PERSHING COUNTY, NV.

Reference (Deposit): U.S. BUREAU OF MINES IC 6902, 1936, 58 PP.

Reference (Deposit): ROCHESTER - NEVADA'S NEWEST AND LARGEST PRECIOUS METAL

Reference (Deposit): PROJECT, AIME PREPRINT, 87-44, 1987, 6 PP.

Reference (Deposit): ROCKY MOUNTAIN PAYDIRT, DEC. 1986, PP. 4A - 6A.

Reference (Deposit): ROCKY MOUNTAIN PAYDIRT, MARCH 1989, P 11A.

Reference (Reserve-Resource): VIKRE, P. G. GEOLOGY AND SILVER MINERALIZATION OF THE

Reference (Reserve-Resource): ROCHESTER DISTRICT, PERSHING COUNTY, NEVADA. PH.D.

Reference (Deposit): WALLACE, R. E., D. B. TATLOCK, N. J. SIBERLING, AND

Reference (Deposit): W. P. IRWIN. GEOLOGIC MAP OF THE UNIONVILLE QUADRANGLE,

Reference (Deposit): PERSHING COUNTY, NEVADA. U.S. GEOL. SURV. QUAD. MAP

Reference (Deposit): GQ-820, 1969, SCALE 1:62,500.

Reference (Deposit): WATSON, B. N. BULK TONNAGE, LOW-GRADE SILVER DEPOSITS -

Reference (Production): PRODUCTION; FROM COEUR D'ALENE MINES CORP. 1996 FORM 10-K,

Reference (Production): P6.

Reference (Reserve-Resource): MINING ENGINEERING. 1978 ANNUAL REVIEW. NEVADA. V. 31,

Reference (Reserve-Resource): NO. 5.

Reference (Reserve-Resource): COEUR D'ALENE MINES CORPORATION, 1996 ANNUAL REPORT, P13 &

Reference (Reserve-Resource): FORM 10-K REPORT, P5.

Reference (Deposit): CAMERON, E. N. GEOLOGY AND MINERALIZATION OF THE

Reference (Deposit): NORTHEASTERN HUMBOLDT RANGE, NEVADA. GEOL. SOC. AM.

Reference (Deposit): BULL., V. 50, 1939, PP. 563-634.

Reference (Deposit): COEUR D'ALENE MINES CORPORATION PRESS RELEASE, DECEMBER 19,

Reference (Deposit): 1983, 1 P.

Reference (Deposit): JENNEY, C. P. GEOLOGY OF THE CENTRAL HUMBOLDT RANGE,

Reference (Deposit): ANNUAL REPORT, 1986, COEUR D'ALENE MINES CORP, PP. 6, 28.

Reference (Deposit): ANNUAL REPORT, 1987, COEUR D'ALENE MINES CORP, P32.

Reference (Reserve-Resource): DISS., STANFORD UNIV., STANFORD, CA, 1977-78, 404 PP.

Reference (Reserve-Resource): ENGINEERING AND MINING JOURNAL. EXPLORATION ROUNDUP.

Reference (Reserve-Resource): ONGOING PROJECTS: U.S. - ASARCO, INC. V. 181, NO. 1,

Reference (Reserve-Resource): 1980, P. 170.

Reference (Reserve-Resource): BONHAM, H. F., JR. RESERVES, HOST ROCKS, AND AGES OF

Reference (Reserve-Resource): BULK-MINEABLE PRECIOUS METAL DEPOSITS IN NEVADA. NV BUR.

Reference (Reserve-Resource): MINES AND GEOL. OFR 82-9, 1982, 4 PP.

Reference (Reserve-Resource): ANNUAL REPORT, 1983, COEUR D'ALENE MINES CORPORATION, P6.

Reference (Reserve-Resource): RANDOL MINING DIRECTORY, 1994/95, U.S. MINES & MINING

Reference (Reserve-Resource): COMPANIES, PP. 345, 346.

Reference (Reserve-Resource): RANDOL MINING DIRECTORY, 1996/97, U.S. MINES & MINING

Reference (Reserve-Resource): COMPANIES, P268.

Reference (Reserve-Resource): PP. 24, 25.

Reference (Reserve-Resource): 1995 FORM 10K, COEUR D'ALENE MINES CORPORATION, PP. 3-5.

Reference (Reserve-Resource): 1995/96, NEVADA MINES DIRECTORY, PP. 7, 28.

Reference (Reserve-Resource): AMERICAN MINES HANDBOOK, 1996, P68.

Reference (Reserve-Resource): 1995 ANNUAL REPORT, COEUR D'ALENE MINES CORPORATION,

Reference (Deposit): ANNUAL REPORT, 1988, COEUR D'ALENE MINES CORP, P32.

Reference (Deposit): 1986 FORM 10K COEUR D'ALENE MINES CORP. P21

Reference (Deposit): 1987 FORM 10K COEUR D'ALENE MINES CORP. P22

Reference (Deposit): 1988 FORM 10K COEUR D'ALENE MINES CORP. P23

Reference (Deposit): EM-KAYAN, MORRISON-KNUDSEN, DEC., 1986.

Reference (Deposit): NEVADA MINING ASSOC., NOV-DEC, 1986, P17.

Reference (Deposit): FIRST QUARTER FORM 10Q, 1989, COEUR D'ALENE MINES CORP. P14.

Reference (Deposit): SECOND QUARTER FORM 10Q, 1989, COEUR D'ALENE MINES CORP P12.

Reference (Deposit): THE MINING RECORD, VOL 107, #34, AUG. 21, 1996, P5.

Reference (Deposit): THE MINING RECORD, VOL 107, #??, AUG. 31, 1996, P5.

Reference (Deposit): SCHRADER, F. C. THE ROCHESTER MINING DISTRICT, NEVADA,

Reference (Deposit): U.S. GEOL. SURV. BULL. 580-M, 1914, PP. 325-273.

Reference (Deposit): SLAVIK, G. (ED.). PINSON MINE, FLORIDA CANYON DESOSIT,

Reference (Deposit): ROCHESTER DISTRICT, AND RELIEF CANYON DEPOSIT. GEOL.

Reference (Deposit): SOC. NV 1984 MEETING, FIELD TRIP, AND ROAD LOG,

Reference (Deposit): SEPT. 21-23, 1984, RENO, NV, 68 PP.

Reference (Deposit): VIKRE, P. G. SILVER MINERALIZATION IN THE ROCHESTER

Reference (Deposit): DISTRICT, PERSHING COUNTY, NEVADA. ECON. GEOL. AND BULL.

Reference (Deposit): SOC. ECON. GEOL., V. 76, NO. 3, 1981, PP. 580-609.

Reference (Deposit): WATSON, B. N. LARGE LOW GRADE SILVER DEPOSITS IN NORTH

Reference (Deposit): AMERICA. WORLD MIN., V. 30, NO. 3, 1977, PP. 44-49.

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Nevada Gold

Nevada has a total of 368 distinct gold districts. Of the of those, just 36 are major producers with production and/or reserves of over 1,000,000 ounces, 49 have production and/or reserves of over 100,000 ounces, with the rest having less than 100,000 ounces. Read more: Gold Districts of Nevada.