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

Troy

Producer in Lincoln county in Montana, United States with commodities Copper, Silver, Lead
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. Mineral rights holdings
  18. Land status
  19. Ownership information
  20. Production statistics
  21. Reserves and resources
  22. Workings at the site
  23. Links to other databases
  24. Bibliographic references
  25. General comments
  26. Reporter information

Geologic information

Identification information

Deposit ID 10124835
MRDS ID W026545
MAS/MILS ID 0300530001
Record type Deposit
Current site name Troy
Alternate or previous names Troy Project, Spar Lake, Old Troy Mine

Geographic coordinates

Point of reference Main Entrance
Geographic coordinates: -115.90464, 48.22927 (WGS84)
Elevation 1341
Location accuracy 100(meters)

Site location context

Political divisions (FIPS codes)

Lincoln(county)

Montana(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Sawtooth Mountain(quadrangle 1:24,000 scale)

Libby(quadrangle 1:100,000 scale)

Kalispell(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Middle Kootenai(hydrologic unit)

Kootenai(hydrologic accounting unit)

Kootenai-Pend Oreille-Spokane(hydrologic subregion)

Pacific Northwest(hydrologic region)

Federal lands

Kootenai National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Montana Lincoln

Public Land Survey System information

Meridian Township Range Section Fraction State
Montana Principal 28 N (29 N) 034 W 6, (35, 36) Montana

Commodities

Commodity Importance
Copper Primary
Silver Primary
Lead Tertiary

Materials information

Materials Type of material
Bornite Ore
Chalcocite Ore
Chalcopyrite Ore
Silver Ore
Covellite Ore
Galena Ore
Quartz Gangue
Barite Gangue
Calcite Gangue

Alteration

  • (Local) calcite

Mineral occurrence model information

Model code 200
USGS model code Unassigned
Deposit model name Sediment-hosted Cu, Revett
Mark3 model number 64

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Quartzite
    Rock type qualifier QUARTZITE & ARGILLITE
    Rock unit name Revett Formation
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
    Rock type qualifier QUARTZ MONZONITE, MAFIC DIKE
    Rock unit name MAFIC DIKE, DRY CREEK STOCK, QUARTZ MONZONITE

Nearby scientific data

Main Entrance (1) Piegan Group: Helena and Wallace Formations
ListMap

Economic information

Geologic structures

Type of structure Local
Structure name BULL LAKE FAULT
Type of structure Local
Structure name East Fault
Type of structure Regional
Structure name SPAR LAKE SYNCLINE

Ore body information

  • General form Three zones up to 60 ft thick, disseminated and stratabound.
    Strike N30W
    Dip 05W
    Thickness 18M
    Length 2260M
    Width 550M
    Area 1113HA
    Depth to top 183M
    Field Value
    Type of Orebody #1 SEDIMENTARY
    Shape of Orebody #1 TABULAR
    Primary mode of Origin OTHER
    Primary Ore Control BEDDING
    Secondary Ore Control LITHOLOGY
    Degree of Wallrock Alter. NONE
    Strike And Dip N30W:05W
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 0
    Min. Thick. Unconsol. Mat. 0
    Total Surface Area (HA) 1113
    Date of Last Modification 840615

Controls for ore emplacement

  • stratabound

Comments on the geologic information

  • BORNITE CHALCOCITE AND CHALCOPYRITE OCCUR IN A RATIO OF 7:3:1
  • DIMENSIONS PERTAIN TO M1C3 (MINE PLAN RESOURCE). DEPOSIT IS STRATABOUND AND PROBABLY FORMED BY EPIGENETIC PROCESSES.
  • BULL LAKE FAULT.

    THE EAST FAULT AT TROY FORMS THE EAST BOUNDARY OF THE ORE DEPOSIT IN MOST PLACES (BURNSIDE AND THOMPSON, 1985). THE MINERAL ZONATION BOUNDARIES SUBPARALLEL THE FAULT (BALLA, HAYES ET AL., 1983); THE CU/PB AND ZN RATIO DECREASES AWAY FROM THE FAULT (LANGE, 1983). THE INFERRED MAJOR DIRECTION OF ORE SOLUTION MOVEMENT WAS TO THE NORTHWEST, PARALLEL TO THE FAULT. THE EAST FAULT ALSO CONTAINS QUARTZ VEINS, VEINLETS, AND STOCKWORKS OF BORNITE, CHALCOPYRITE, AND OTHER SULFIDES THAT ARE VERY HIGH-GRADE, BUT RETAIN THE RELATIVE AG/CU PROPORTIONS OF THE DISSEMINATED ZONES THEY CUT (BALLA, HAYES, ET AL., 1983)

Economic information about the deposit and operations

Operation type Underground
Development status Producer
Commodity type Metallic
Deposit size Medium
Significant Yes
Discovery year 1963
Mining method Open Stope - Room and Pillar
Year of first production 1981
Plant type Beneficiation (Mill)
Plant subcategory Flotation
Milling method Flotation
Production years 1981-1993, 2004-present

Comments on exploration

  • From Boleneus and other (2005):
    C. Weatherell (Bear Creek Mining Co.) recognized stratabound mineralization in 1963. This led to regional exploration program in 1964 and discovery of many other Cu-Ag occurrences. In 1964-1972, 112 diamond drill holes and 6200 ft of underground workings and geologic studies were completed. In 1973, the property was leased to Asarco Inc. The core claim block was patented in 1977. In 1979, mining and environmental plans were approved and access tunnel and plant construction began. In 1981, production began. In 1982, the mine reached full production level of 8,500 tons/day using trackless room-and-pillar mining method.

Mining district

District name Troy

Mineral rights holdings

Type of mineral rights Patented

Land status

Ownership category National Forest
Area name Kootanai National Forest

Ownership information

  • Type Owner-Operator
    Owner Asarco (American Smelting And Refining Co.)
    ID 2401467
    Interest 75
    Home office New York
    Year 2005
    First year 1973
    Last year 1999
  • Type Owner
    Owner Kennecott Minerals Corp.
    ID 2401467
    Interest 25
    Home office New York
    Year 2005
    First year 1963
    Last year 1999
  • Type Owner
    Owner Revett Silver
    Interest 100
    Home office Montana
    Year 2009
    First year 1999

Production statistics

  • Year 1981
    Description Produced After Refining Kilograms Of Cu 2906299 Kilograms Of Copper
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 2906.29mt
  • Year 1981
    Description Produced After Refining.Ounces Of Silver 764500 Ounces Of Silver
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Silver Silver 23778611.22g
  • Year 1982
    Description 16314000 Kilograms Of Copper
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 1631.4mt
  • Year 1982
    Description 4210699 Ounces Of Silver
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Silver Silver 130967396.34g
  • Year 1983
    Description 14736000 Kilograms Of Copper
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 1473.6mt
  • Year 1983
    Description 3963700 Ounces Of Silver
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Silver Silver 123284867.63g
  • Year 1984
    Description 17200000 Kilograms Of Copper
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Copper Copper 1720mt
  • Year 1984
    Description 4269000 Ounces Of Silver
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Silver Silver 13278076.03g
  • Year 1993
    Period 1981-1993
    Material 44.4 million ounces of silver and 180,000 tons of copper
  • Year 1993
    Description Ag 812000 Oz
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Silver Silver 25256026.57g

Comments on the production information

  • From Revett Minerals (2009)
    Production Rate: 4,400 tons per day ore (avg. at planned production)
    1.5 million oz. Silver per annum
    15.5 million pounds Copper per annum
  • 1981-1993 production from Asarco Inc. 1981-93 SEC Form 10K.
  • From Reipas and Couture (2005, p. v.): "ASARCO leased the Troy Project from Kennecott in 1973 with plans to build a mine. Underground production began in 1981 and lasted for a period of 12 years ending in 1993. The mine produced at a nominal rate of 8,500 tons per day which yielded a total of
    44.4 million ounces of silver and 180,000 tons of copper upon closure in 1993."

Reserves and resources

  • Type In-situ
    Estimate year 2009
    Reserves 9434721mt ore
    Indicated 17400000mt ore
    Remarks Data from http://www.revettminerals.com/revProReserves.php\nReserves given in English Units (CIM standards):\nReserves (Proven & Probable): 10.4 million tons @ 1.19opt Ag & 0.57% Cu (as of 12.31.08)\nSilver: 12.4 million ounces\nCopper: 117.7 million pounds\nProven is 4,000,000 tons at 1.34 oz/t Ag, 0.69% Cu\nProbable is 6,400,000 tons at 1.10 oz/t Ag, 0.49% Cu\nMeasured is 42,200,000 tons at 1.42 oz/t Ag, 0.70% Cu\nIndicated is 17,400,000 tons at 0.99 oz/t Ag, 0.44% Cu
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 33.01 g/mt Silver Primary 2009
    Copper Cu 0.57 wt-pct Copper Primary 2009
  • Type In-situ
    Estimate year 2004
    Proved 4170000mt ore
    Probable 3719000mt ore
    Measured 41280000mt ore
    Inferred 1361000mt ore
    Remarks Converted English Units to Metric\nCategory Mineral Resources*\nAg opt Cu % Million Tons\nMeasured 1.51 0.76 45.5\nIndicated 1.69 0.64 8.5\nMeasured and\nIndicated 1.55 0.74 54.0\nInferred 1.67 0.36 1.5\n*Stated at a US$11NSR/Ton cut-off\nTable II: Troy Project, Montana, Statement of Mineral Reserves ? July 2004.\nProven and Probable Reserves*\nCategories Ag opt Cu % NSR Million Tons\nProven 1.47 0.69 $14.47 4.6\nProbable 1.69 0.61 $14.34 4.1\nProven and Probable 1.57 0.65 $14.41 8.7
  • Type In-situ
    Estimate year 1984
    Measured 52003000mt ore
    Demonstrated 104006000mt ore
    Total resources 104006000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 54.2 g/mt Silver Major 1984
    Copper Cu 0.76 wt-pct Copper Major 1984
  • Type In-situ
    Estimate year 1984
    Measured 39283000mt ore
    Indicated 39283000mt ore
    Demonstrated 78566000mt ore
    Inferred 39283000mt ore
    Total resources 117849000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 52.8 g/mt Silver Major 1984
    Copper Cu 0.75 wt-pct Copper Major 1984
  • Type In-situ
    Estimate year 1990
    Total resources 58060800mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 47.9 g/mt Silver Major 1990
    Copper Cu 0.75 wt-pct Copper Major 1990
  • Type In-situ
    Estimate year 0
    Demonstrated 58000000mt ore
    Total resources 58000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 52.8 g/mt Silver Major 0
    Copper Cu 0.75 wt-pct Copper Major 0
  • Type In-situ
    Estimate year 1995
    Demonstrated 10277000mt ore
    Total resources 10277000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 49 g/mt Silver Major 1995
    Copper Cu 0.65 wt-pct Copper Major 1995
  • Type In-situ
    Estimate year 1996
    Measured 10886000mt ore
    Demonstrated 10886000mt ore
    Total resources 10886000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 49 g/mt Silver Major 1996
    Copper Cu 0.65 wt-pct Copper Major 1996

Comments on the reserve resource information

  • REC 2-RESERVES & GRANDES FROM ASARCO INC. 1984 AR P. 12.
  • ASARCO, INC., 1988 AR, P15.
  • ASARCO 1978 10K. EXPECTED POTENTIAL 4.2 MILLION OZ SILVER PER YEAR FOR ABOUT 16 YEARS. DEPOSIT REPORT AUTHOR: SCHUMACHER. MINE SHUT DOWN IN APRIL 1993. RESERVES FROM PAY DIRT FEBRUARY 1993, P. 8A.
  • M1C3=MINE PLAN RESOURCE RESOURCES ARE NONCUMULATIVE
  • Portergeo.com.au lists the "pre-mining geological reserve" as:
    58 Mt @ 0.76% Cu, 54 g/t Ag, to 64 Mt @ 0.74% Cu, 54 g/t Ag.
  • See page vii in Reipas and Couture (2005) for Cu and Ag tonnage and grade for each type of resource category.
    Proven - 1.47 opt Ag, 0.69 % Cu
    Probable - 1.69 opt Ag, 0.61% Cu
    Measured - 1.51 opt Ag, 0.76% Cu
    Indicated - 1.69 opt Ag, 0.64% Cu
    Inferred - 1.67 opt, 0.36% Cu

Workings at the site

  • Type of workings Underground
    Field Value
    Room and Pillar Mining Method Estimated Percent Recovery 75 HARDROCK FISSURED WITH MODERATE WATER
    Rock Characteristics ONE SYSTEM OF WEAKNESS PLANES
    Slope of Incline 13
    Year of Information 1984

Comments on the workings information

  • NO MAJOR ENVIRONMENTAL PROBLEMS ENCOUNTERED.

Comments on other economic factors

  • THE TROY MINE PUMPS ABOUT $22 M INTO THE LOCAL ECONOMY ASARCO ANNOUNCED THAT THE TROY MINE CONTRIBUTES $8M TO ASARCOS PRETAX EARNING ASSUMING A COPPER PRICE OF $.72 /LB $10/OZ SILVER AND A DEDUCTION OF 25 PCT. ROYALTY AFTER DEDUCTING EXPENSES DUE KENNECOTT MINERALS
  • INCLINE ADIT SLOPES UPWARD FROM MILLSITE TO OREBODY.
  • JACK BINGHAM STATED THAT THE AVERAGE MILL FEED IS AVERAGING ABOUT 6 PCT HIGHER THAN EXPECTED. CURRENTLY THE CONCENTRATE IS SHIPPED TO ASARCOS TACOMA WA SMELTER AND ON TO THEIR AMARILLO TX REFINERY.

Reference information

Bibliographic references

  • Deposit

    BALLA , J. C. ASARCO MANAGER NORTHWESTERN EXPLORATION DIVISION. PERSONAL COMMUNICATION, 1984.

  • Reserve-Resource

    Revett Minerals Inc., 2009, Troy Mine: http://www.revettminerals.com/documents/Revett_Fact_Sheet_3.26.09.pdf, accessed July 23, 2009.

  • General

    Reipas, Ken, and Couture, Jean-Francois, 2005, Independent Technical Report on the Troy Cu-Ag Project, Montana, U.S.A. for Revett Silver Company: SRK Consulting (CANADA) INC., Toronto, Ontario, SRK project Number: 3UR006.02, 223 p. [accessed January 5, 2010, at http://www.revettminerals.com/revOpTroyReports.php].

  • Geology

    Hayes T S, Einaudi M T 1986 - Genesis of the Spar Lake strata-bound Copper-Silver deposit, Montana: Part I. Controls inherited from sedimentation and preore diagenesis: in Econ. Geol. v81 pp 1899-1931

  • Reserve-Resource

    Boleneus, D.E., Appelgate, L.M., Stewart, J.H., and Zientek, M.L., 2005, Stratabound Copper-Silver Deposits of the Mesoproterozoic Revett Formation, Montana and Idaho: U.S. Geological Survey Scientific Investigations Report 2005?5231, 66 p.

  • Deposit

    BEAR CREEK MINING COMPANY. PRIVATE COMPANY REPORTS. UNPUBL.

  • Deposit

    BINGHAM, J. P., MANAGER OF ASARCO'S TROY MINE. PERSONAL COMMUNICATION, 1984.

  • Deposit

    ASARCO'S NEW TROY MINE. PAPER PRESENTED AT THE 89TH ANNU.NORTHWEST MINING CONVENTION, SPOKANE, WA, DEC.1-3, 1983.

  • Deposit

    TROY PROJECT OPERATING PLAN. SUBMITTED TO U.S. FOREST SERVICE, MAY 14, 1976.

  • Deposit

    COST REFERENCE GUIDE FOR CONSTRUCTION EQUIPMENT. EQUIPMENT GUIDE BOOK COMPANY, PALO ALTO, CA, 1983.

  • Deposit

    DAYTON, S. H. ASARCO'S TROY MINE. ENG. AND MIN. J., FEB 1983, V. 184, NO. 9, PP. 40-46.

  • Deposit

    DILLARD, G. TROY OPERATION MAKES ASARCO NATION'S LEADING SILVER PRODUCER, PAY DIRT BIG SKY EDITION, DEC. 1982. PP 5-7.

  • Deposit

    EARHART, R.L., M.D. KLEINKOPF, D.M. WILSON, D.J. GRIMES, AND N.T. ZILKA. MINERAL RESOURCES OF SCOTCHMAN PEAK WILDERNESS STUDY AREA. U.S. GEOL. SURV. OFR 76-706, 1976, 136 PP.

  • Deposit

    GIBSON, R. GEOLOGY AND ORE DEPOSITS OF THE LIBBY QUADRANGLE, MONTANA. U.S. GEOL. SURV. BULL. 956, 1948, 131 PP.

  • Deposit

    JAYNE, D. A NORTHWEST METALS CONFERENCE-SPONSORED TOUR OF THE TROY MINE. PERSONAL NOTES, APR. 28, 1982.

  • Deposit

    MINING JOURNAL. ASARCO'S TROY MINE. OCT. 1981, PP. 2-4.

  • Deposit

    MONTANA DEPARTMENT OF REVENUE. REVENUE RECORDS. 1982, 1983.

  • Deposit

    PAY DIRT MAGAZINE. ASARCO WORKING TO CLEAN UP TAILING TAILINGS PROBLEM AT TROY OPERATION. BIG SKY EDITION, JUNE, 1983, P. 23A.

  • Deposit

    SKILLINGS' MINING REVIEW. ASARCO'S INCORPORATED NEW TROY SILVER-COPPER MINE. NOV. 20, 1982.

  • Deposit

    STEARNS-ROGER, INC. ENVIRONMENTAL BASELINE INFORMATION OF THE MOUNT VERNON REGION--MONTANA. PREPARED FOR ASARCO, JAN. 31, 1975, UNPUBL.

  • Deposit

    STRAAM ENGINEERS, INC. CAPITAL AND OPERATING COSTS ESTIMATING SYSTEM HANDBOOK. BUMINES CONTRACT NO. J0255026, 1979, 374 PP.

  • Deposit

    WESTERN MINE ENGINEERING MING COST SERVICE. SPOKANE, WA 1983

  • Deposit

    WHITE, T. ASARCO'S TACOMA SMELTER. PERSONAL COMMUNICATION, 1984.

  • Deposit

    MONT. BUREAU OF MINES AND GEOL. BULLETIN 129, 1991,

  • Deposit

    ASARCO INC., 1994 10K, P.A18, A21.

  • Deposit

    ASARCO INC. 1995 ANNUAL REPORT, P.11.

  • Deposit

    1995 ASARCO'S 1995 10K, P. A21.

General comments

Subject category Comment text
Deposit ACCORDING TO ASARCO, THE SPAR LAKE DEPOSIT IS ABOUT 7,400 FEET LONG, 1800 FEET WIDE, AND AVERAGES ABOUT 60 FEET IN THICKNESS- AVERAGE GRADEIS 0.74% Cu AND 1.54 TOZ Ag/ ST
Deposit ORE MINERALS OCCUR AS DISSEMINATIONS, CLOTS, BEDDING AND SHEAR PLANE CONCENTRATIONS, AND FRACTURE FILLINGS (BURNSIDE AND THOMPSON, 1985).

Reporter information

Type Date Name Affiliation Comment
Reporter 17-JUN-97 Clarke, Donald U.S. Bureau of Mines
Updater 23-JUL-09 Causey, J. Douglas U.S. Geological Survey

Beyond USGS

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

Current status (per MSHA)

StatusNonProducing since 05/04/2026
MSHA mine ID2401467
Mine name (MSHA)Troy Mine
Current operatorTroy Mine Inc.
Current controller (parent)Revett Silver Company
Mine typeUnderground (Metal / non-metal)

MSHA cross-reference per the original MRDS record. Mine status and operator reflect MSHA's last published Mines export (February 2025); MSHA's public bulk feed has been unavailable since, so this may be out of date. See the Mine Data Retrieval System for current status.

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

Operator history (post-MRDS)

MRDS records operators as of each record's last update (≤ 2019). Some of the operators listed here have since changed hands or dissolved:

  • Asarco (American Smelting And Refining Co.) — acquired by Asarco LLC, subsidiary of Grupo México (2009)
    American Smelting and Refining Co. Filed Chapter 11 in 2005; acquired out of bankruptcy by Grupo México in 2009.

Curated by qvyshift.com from publicly-reported M&A activity (SEC filings, press releases, USGS Mineral Yearbooks). Not authoritative — verify against primary sources before relying on it. The MSHA panel above is the current authoritative source for actively-permitted mines.

Maps centered on this site