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Grassy Mountain Mine

Plant in Malheur county in Oregon, United States with commodities Gold, Silver
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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. Mineral occurrence model information
  8. Nearby scientific data
  9. Ore body information
  10. Economic information about the deposit and operations
  11. Mineral rights holdings
  12. Land status
  13. Ownership information
  14. Reserves and resources
  15. Workings at the site
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10250858
MRDS ID OR07000
MAS/MILS ID 0410450111
Record type Site
Current site name Grassy Mountain Mine
Alternate or previous names Musgrove Creek, Grassy Mtn Property
Related records 10054018

Geographic coordinates

Point of reference Ore Body
Geographic coordinates: -117.3624, 43.66737 (WGS84)
Elevation 1146
Location accuracy 100(meters)

Site location context

Political divisions (FIPS codes)

Malheur(county)

Oregon(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Grassy Mountain(quadrangle 1:24,000 scale)

Vale(quadrangle 1:100,000 scale)

Boise(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Malheur(hydrologic unit)

Middle Snake-Boise(hydrologic accounting unit)

Middle Snake(hydrologic subregion)

Pacific Northwest(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management OR)

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

BLM(Federal land areas administered by BLM)

Geographic areas

Country State County
United States Oregon Malheur

Public Land Survey System information

Meridian Township Range Section Fraction State
Willamette 022 S 044 E 08 SW Oregon

Commodities

Commodity Importance
Gold Primary
Silver Secondary

Mineral occurrence model information

Model code 104
USGS model code 25a
Deposit model name Hot-spring Au-Ag
Mark3 model number 45

Nearby scientific data

Ore Body (1) -117.3624, 43.66737
ListMap

Economic information

Ore body information

  • Field Value
    MAS Matrix # 1
    MAS Column # 1
    Type of Orebody #1 DISSEMINATED
    Shape of Orebody #1 UNKNOWN
    Type of Orebody #2 BRECCIA FILL
    Primary mode of Origin HYDROTHERMAL
    Primary Ore Control FRACTURING
    Secondary Ore Control FAULTING
    Degree of Wallrock Alter. UNKNOWN
    Type of Wallrock Alter. #1 SILICIFICATION
    Type of Wallrock Alter. #2 PYRITIZATION
    Date of Last Modification 910814

Economic information about the deposit and operations

Operation type Surface
Development status Plant
Commodity type Metallic
Significant Yes
Discovery year 1986
Mining method Open Pit
Plant type Leach
Plant subcategory Hydromet
Milling method Hydrometallurgy Unspecified

Mineral rights holdings

Type of mineral rights Located Claim

Land status

Ownership category BLM Administrative Area

Ownership information

  • Type Owner-Operator
    Owner Atlas Corp.
    Interest 100
    Home office Colorado
    Year 1992
    First year 1986
  • Type Operator
    Owner Newmont Exploration, Ltd. (Newmont Gold Co.)
    Home office Colorado
    Year 1996
    First year 1992

Comments on the production information

  • YIELD IS 2,156 KG/A AU/AG DORE OF UNDETERMINED GRADE.
  • CAPACITY IS COMBINED PRODUCT OF MILL & SOLUTION FROM HEAP LEACH. CAPACITY OUTPUT PRODUCTION COST, AND INVESTMENT IS COMBINED CIL AND HEAP LEACH.

Reserves and resources

  • Type In-situ
    Estimate year 1992
    Demonstrated 14424162mt ore
    Total resources 14424162mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 2.13 g/mt Gold Major 1992
  • Type In-situ
    Estimate year 1994
    Demonstrated 14500000mt ore
    Total resources 14500000mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 2.13 g/mt Gold Major 1994
  • Type In-situ
    Estimate year 1995
    Demonstrated 14500441mt ore
    Total resources 14500441mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 2.13 g/mt Gold Major 1995
    Silver Ag 5.29 g/mt Silver Minor 1995
  • Type In-situ
    Estimate year 1997
    Demonstrated 14514955mt ore
    Total resources 14514955mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 2.13 g/mt Gold Major 1997

Comments on the reserve resource information

  • THIS MATERIAL HAS BEEN RECLASSIFIED AS MINERALIZED MATERIAL.
  • 1994 RESERVES FROM SKILLINGS MINING REVIEW MARCH 5, 1994. RANDOL, 1996/97 RESERVES RECLASSIFIED AS MINERALIZED MATERIAL PENDING ADDITIONAL EVALUATION. R-RECORDS 2 AND 3. R-RECORD 4 SILVER GRADE NOT GIVEN: POSSIBLY SAME AS R-RECORD THREE.
  • SULFIDE ORE FOR CIL PLANT. OXIDE ORE FOR HEAP LEACH. M3C1=M1C1 +M261. M3C1 IS SOURCE OF ORE.

Workings at the site

  • Type of workings Surface
    Area 34HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 1
    Status of Mining Method PROPOSED
    Mining Method OPEN PIT
    Percent Waste Rock 84.9
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 6.1
    Max. Pit Slope (degrees) 43
    Capacity 5151
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 7500000
    Unit Production Cost 7.79
    Units of Production $/MT ORE
    Operating Days per Year 365
    Operating Shifts per Day 2
    Year of Information 1990

Comments on other economic factors

  • FIRST PRODUCTION EXPECTED IN EARLY 1993. RESERVE SAID TO BE 1,200,000 OZ CONT. AU. CAPACITY LIKELY TO BE 100,000 OZ/YR.

Reference information

Bibliographic references

  • Ownership

    AMERICAN MINES HANDBOOK'S, 1993, 28; 1996, P33; 1997, P39.

  • Ownership

    THE MINING RECORD, VOL., 107, #42, OCT., 16, 1996, P1.

  • Reserve-Resource

    NEWMONT MINING CORP., 1993 ANNUAL REPORT, P.17.

  • Reserve-Resource

    NEWMONT GOLD CO., 1994 10-K, P.13,14.

  • Reserve-Resource

    NEWMONT GOLD CO., 1995 ANNUAL REPORT, P.41.

  • Reserve-Resource

    AMERICAN MINES HANDBOOK, 1997, P39.

  • Deposit

    DOGAMI MLR 23-0195

  • Deposit

    AMERICAN METALS MARKET, 10-29-96, V104 N210, P.7.

  • Deposit

    EIS FILES, GRASSY MOUNTAIN PROJECT, OREGON.

  • Deposit

    ROCKY MOUNTAIN PAY DIRT, #171, 12/93, P.3A.

  • Deposit

    RANDOL MINING DIRECTORY 1993/94, P.310.

  • Deposit

    RANDOL MINING DIRECTORY 1994/95, P.376.

  • Deposit

    ROCKY MOUNTAIN PAY DIRT, 2-93, P.24A

  • Deposit

    ROCKY MOUNTAIN PAY DIRT, 4-93, P.3A.

  • Deposit

    AMERICAN METAL MARKET, V104 N7, 1-10-96, P.2.

  • Deposit

    NEWMONT MINING CORP., 1994 ANNUAL REPORT, P.27-29.

  • Deposit

    RANDOL, MINING DIRECTORY 1996/97, U.S. MINES & MINING

  • Deposit

    COMPANIES, P295.

General comments

Subject category Comment text
Deposit AS OF APRIL, 97 MINE IS NOT IN PRODUCTION. STATUS WILL BE BE CHANGED FROM MINERAL LOCATION TO EXP PROSPECT: NEWMONT HAS A 35 YR LEASE WHICH CAN BE EXTENDED TO 65 YR. LEASE WAS SINGED IN 1992. COSR OF LEASE $22.5 MILLION. PROPERTY INCLUDES MUSGROVE CREEK PROPERTY.

Reporter information

Type Date Name Affiliation Comment
Reporter 25-JUN-97 Buckingham, David A. U.S. Bureau of Mines

Beyond USGS

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

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