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Henderson Mine

Producer in Clear Creek county in Colorado, United States with commodities Molybdenum, Lead, Tungsten, Tin, Zinc, Iron
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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. 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. Reporter information

Geologic information

Identification information

Deposit ID 10012410
MRDS ID D008022
MAS/MILS ID 0080190055
Record type Deposit
Current site name Henderson Mine

Comments on the site identification

  • *****SEE RELATED DEPOSIT Urad Deposit ID 10012413

Geographic coordinates

Point of reference Plant
Geographic coordinates: -105.84199, 39.76916 (WGS84)
Elevation 3170
Location accuracy 1000(meters)
Relative position 8.5 MILES N87W FROM EMPIRE. At main plant site. Visible on aerial imagery. Point chosen south of main access road off of US Hwy. 40. Accuracy of the point to represent the plant is within 100 m, but the main deposit is under Red Mountain which is about 1 km south.

Site location context

Political divisions (FIPS codes)

Clear Creek(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Berthoud Pass(quadrangle 1:24,000 scale)

Denver West(quadrangle 1:100,000 scale)

Denver(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Clear(hydrologic unit)

South Platte(hydrologic accounting unit)

South Platte(hydrologic subregion)

Missouri(hydrologic region)

Federal lands

Arapaho and Roosevelt National Forests(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Colorado Clear Creek

Public Land Survey System information

Meridian Township Range Section Fraction State
6th Principal 003S;003S 074W;075W 19,30;24,25 Colorado
6th Principal 003 N 076 W 24 SW Colorado

Comments on the location information

  • 3 SHAFTS AND SURFACE FACILITIES ON WEST FORK CLEAR CREEK, 8-1/2 MILES WEST OF EMPIRE (SEC. 19, T 3 S, R 75 W; SEC. 24, T 3 S, R 76 W). MINE DEVELOPED UNDER RED MTN. (SEC. 25, T 3 S, R 76 W; SEC. 30, T 3 S, R 75 W). LAT-LONG IS TOP OF RED MTN. ; INFO FROM LAND.ST :(1978)

Commodities

Commodity Importance
Molybdenum Primary
Lead Secondary
Tungsten Critical Secondary
Tin Critical Secondary
Zinc Critical Tertiary
Iron Tertiary

Materials information

Materials Type of material
Molybdenite Ore
Fluorite Gangue
Galena Gangue
Hematite Gangue
Huebnerite Gangue
Magnetite Gangue
Pyrite Gangue
Quartz Gangue
Sericite Gangue
Sphalerite Gangue
Topaz Gangue
Rhodochrosite Gangue

Alteration

  • (Local) Argillic Griesen Below Ore Body. Quartz, Quartz-Topaz-Magnetite, Quartz-Sericite-Pyrite, Argillic, And Propylitic Zones Progressively Above Ore Body

Analytical data

Result AVG. 0.49 % MOS2
Result HIGH-GRADE ASSAY G.T. 0.8 % MOS2

Comments on the analytical data

  • DESBOROUGH AND MIHALIK (1980) REPORT ELECTRON MICROPROBE ANALYSES OF VARIETY OF ACCESSORY MINERALS CONTAINING MANY HEAVY AND TRACE METALS AND RARE EARTHS--ILMENORUTILE CONTAINING TI NB TA FE SN TH U MN Y SC; AESCHYNITE CONTAINING TI NB FE TA SN U TH MN Y LA CE PR ND SM EU GD TB DY ER YB TM LU; COLUMBITE CONTAINING TI FE MN TA SC SN DY U TH Y; URANIFEROUS THORITE AND MONAZITE, TITANIFEROUS MAGNETITE. ANALYSIS OF THREE SPECIMENS OF COLUMBITE GIVE WT % OF FOLLOWING OXIDES (NA=NOT ANALYZED): 61.9, 70.5 64.8 % NB2O5; 7.6, 7.4, 17.6 % TIO2; 12.2, 16.9, 6.6 % FEO; 7.5, 1.0, LT 0.1 % MNO; 2.5, 3.8, 3.8 % TA2O5; 3.0, NA, NA % SC2O3; 0.8, NA, NA % SNO2; 1.7, NA, NA % DY2O3; 0.1, LT 0.1, 2.4 % UO2; 0.1, LT 0.1, 1.0 % THO2; LT 0.1, LT 0.1, 0.8 % Y2O3. ANALYSIS OF FOUR AESCHYNITE GRAINS GIVES WT % OF PRINCIPAL HEAVY AND TRACE METALS (ND=NOT DETECTED): 17.6, 17.1, 17.9, 4.9 % TIO2; 30.5, 32.0, 30.9, 39.3 % NB2O5; 1.8, 2.2, 1.5, 13.8 % FEO; 3.2, 3.7, 3.6, 3.7 % TA2O5; 0.3, 0.2, 0.3, 1.0 % SNO2; 13.2, 12.8, 15.8, 5.1 % THO2; 4.6, 2.8, 4.9, 12.2 % UO2; ND, ND, 0.1, 1.1 % SC2O3; 0.1, 0.1, 0.1, 2.6 % MNO;

Mineral occurrence model information

Model code 50
USGS model code 16
Deposit model name Climax Mo

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Granitoid
    Rock unit name Urad porphyry
    Stratigraphic age (youngest) Oligocene
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid
    Rock unit name Primos porphyry
    Stratigraphic age (youngest) Oligocene
  • Host or associated Host
    Rock type Plutonic Rock > Granitoid > Granite
    Rock unit name Henderson granite
    Stratigraphic age (youngest) Oligocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock type qualifier 7 units- oldest to youngest:Tungsten Slide; East Knob; Square quartz porphyry; Rhyolite porphyry of radial dike swarm; Red Mtn. porphyry; Urad porphyry; Primos porphyry; Henderson granite
    Rock unit name Red Mountain Complex- multi-phase intrusive complex of high silica, alkali-rich rhyolite, and granite porphyry
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
    Rock type qualifier Composite batholith of 200 sq. mi in diamension that intrudes the metasedimentary schists of the Idaho Springs Formation. A coarse grained massive to trachytoid, slightly porphyritic biotite-muscovite granite and a fine-to medium-grained variant
    Rock unit name Silver Plume Granite

Nearby scientific data

Plant (1) -105.84199, 39.76916
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Front Range Uplift, Silver Plume Batholith, Colorado Mineral Belt
Type of structure Local
Structure description Straight Cr., Vasquez Cr., Loveland Pass-Berthoud Pass Fault Zones

Ore body information

  • General form ELLIPTICAL IN PLAN, UMBRELLA SHAPED IN PROFILE
    Thickness 243.84M
    Length 914.4M
    Width 670.56M
    Depth to top 1005.84M
    Depth to bottom 1798.32M

Controls for ore emplacement

  • Fractures On Roof And Flanks Of Multiple-Stage Intrusion

Comments on the geologic information

  • The Henderson orebody is hosted in Oligocene rhyolite porphyry intrusive rocks under Red Mountain; the deposit is an umbrella-shaped stockwork, about 3000 ft by 2300 ft in plan, and 600 to 1000 ft. in thickness. The orebody is compound, having upper, middle and lower lobes, where the highest grade ore occurs where the lobes overlap. (Wallace and others, 1978)
    Originally the deposit contained 437 million tons of ore at an average grade of 0.38% MoS2 and a 0.2% MoS2 grade cutoff. (Seedorf and Einaudi, 2004)
  • The Henderson and Urad stockwork molybdenite orebodies at Red Mountain are two seperate but related deposits. The Urad orebody was formed first at a shallow depth, the Henderson formed deeper within the igneous complex, and is the larger. Together they constitute one of the largest concentrations of molybdenite in the world. The Urad and Henderson deposits at Red Mountain are related to a Oligocene multi-phase rhyolitic intrusive center named the Red Mountain Complex that intrudes the Precambrian Silver Plume Granite batholith within a northeast trending Precambrian shear zone, near the western edge of the Colorado Mineral Belt. The intrusion of the Red Mountain Complex is closely related to the two major northeast trending Tertiary faults, the Berthoud Pass and the Vasquez Pass. (Wallace and others, 1978)
  • From deleted record 10190619 (old MAS 0080190055);
    MAS Matrix # : 1
    MAS Column # : 1
    Type of Orebody #1 : STOCKWORK
    Shape of Orebody #1 : MASSIVE
    Type of Orebody #2 : DISSEMINATED
    Shape of Orebody #2 : TABULAR
    Type of Orebody #3 : FISSURE VEIN
    Shape of Orebody #3 : OTHER
    Primary mode of Origin : MAGMATIC DIFFER
    Secondary mode of Origin : HYDROTHERMAL
    Primary Ore Control : IGNEOUS
    Secondary Ore Control : FAULTING
    Degree of Wallrock Alter. : SLIGHT
    Type of Wallrock Alter. #1 : POTASSIC
    Type of Wallrock Alter. #2 : PROPYLITIC
    Minimum Depth to Top : 870
    Avg. Thick. Unconsol. Mat. : 1
    Min. Thick. Unconsol. Mat. : 0
    Date of Last Modification : 800319
  • AVERAGE DEPTH TO MINERALIZATION IS MEASURED FROM THE TOP OF RED MOUNTAIN. DIMENSIONS OF THE ORE BODY ARE BASED ON A 0.2 PERCENT MOS2 CUTOFF GRADE.

Economic information about the deposit and operations

Operation type Underground
Development status Producer
Commodity type Metallic
Deposit size Large
Significant Yes
Discovery year 1965
Discoverer Amax
Mining method Caving Methods - Block Caving
Year of first production 1976
Milling method Flotation

Mining district

District name Empire District
District name Henderson/Urad
District name Henderson
District name Dailey-Jones Pass District

Mineral rights holdings

Type of mineral rights Private Lease
Type of mineral rights Patented
Type of mineral rights Fee Ownership

Land status

Ownership category Private

Ownership information

  • Type Owner-Operator
    Owner Freeport-McMoRan Copper and Gold Inc
    Interest 100
    Home office 333 North Central Ave\nPhoenix AZ 85004 \nUnited States
    Year 2011
    First year 2007
  • Type Owner-Operator
    Owner Cyprus-Amax Minerals Co.
    Interest 100
    Year 1994
    First year 1994
  • Type Owner-Operator
    Owner Climax Molybdenum Co., Division Of American Metal Climax Inc. (Amax)
    First year 1981

Production statistics

  • Year 1979
    Ore mined 8411000mt
  • Year 1980
    Ore mined 9369000mt
  • Year 1981
    Ore mined 8833000mt
  • Year 1982
    Ore mined 3494000mt

Comments on the production information

  • In operation since 1976, Henderson has produced more than 160 million tons of ore and 770 million pounds of molybdenum during the past 27 years. (Climax Molybdenum web site)

Reserves and resources

  • Type In-situ
    Estimate year 1996
    Measured 181000000mt
    Remarks .23% from old MAS record 0080190055.
    Commodity Subtype Grade units Group Importance Year
    Molybdenum Mo 0.23 wt-pct Molybdenum Primary 1996
  • Type In-situ
    Estimate year 1979
    Reserves 260000000mt
    Remarks USBM, 1979
    Commodity Subtype Grade units Group Importance Year
    Molybdenum 0.49 wt-pct Molybdenum Primary 1979
  • Type In-situ
    Estimate year 1994
    Indicated 163700000mt
    Remarks .38% from old MAS record.
    Commodity Subtype Grade units Group Importance Year
    Molybdenum Mo 0.38 wt-pct Molybdenum Primary 1994

Comments on the reserve resource information

  • At the end of 2005, reserves were 150.7 million tons at a grade of 0.21% molybdenum. (Phelps Dodge 2005 Annual Report)
  • From deleted record 0080190055:
    THE RESERVES ESTIMATE REPRESENTS GEOLOGIC RESERVES MINUS PRODUCTION FROM 1976 THROUGH 1978. THE MINES MAGAZINE, VOL. 57, NO. 10, P. 36, OCT. 1967.
  • FIRST EST. FROM TERRY FITZSIMONS, AMAX, 1980 PERS. COMM.; SECOND EST. FROM 1980 AMAX ANNUAL REPORT
  • From deleted record 0080190055:
    Q1 MATRIX REPRESENTS GEOLOGIC RESERVES MINUS PRODUCTION FROM 1976 THROUGH 1978.THE P50 LEVEL IS 30 PERCENT HIGHER THAN THE P75 LEVEL AND THE P25 LEVEL IS 30 PERCENT HIGHER THAN THE P50 LEVEL. EVALUATION BASED ON P75 LEVEL. PROPERTY EVALUATION WILL BE RUN ON COL. 4. PROPERTY LIFE = Q1 COL1 ROW2 X RECOVERY / (DAILY CAPACITY X DAYS/YEAR). THE ABOVE EQUATION APPROXIMATES THE ESTIMATED MINE LIFE 24 YEARS BECAUSE IT REFLECTS THE MINING RESERVE AFTER DILUTION. THE MINING RESERVE GIVEN BY COMPANY PERSONNEL AT THE TIME OF EVALUATION WAS 260,000,000 ST AT 0.39% MOS2. THE DATA BASE RESERVES REFLECT THIS VALUE AFTER THE RECOVERY FACTOR IS APPLIED AND THE FEEDS REFLECT THE DILUTED GRADE. BUT IN ORDER TO CALCULATE A MASS BALANCE O DATA BASE THE LIFE HAD TO BE CHANGED TO 30 YEARS. MOST RECENT RESERVE ESTIMATE AT THE TIME OF THIS REVIEW. SOURCE: AMAX 1985 FORM 10-K, P. 7. RESERVE ESTIMATE AS OF DEC. 31, 1985 AND REPRESENTS DILUTED RECOVERABLE TONNAGE.
  • From deleted record 0080190055:
    AMAX 1978 10K, P5. TOTAL MANPOWER 7/11/88 350. ANNUAL MO PRODUCTION EST. 25MLB/Y, OP.COST EST. $1.71/LB MO.RESERVES PER 10K 12/31/87 200,490,000 TONS@ 0.222MO.RESERVES 1/1/89 195,047,000MT O.222%MO. ADIT 1994 UPDATE: PRODUCTION BASED ON CAPACITY OF MILL: 28,000 SHTONS/DAY, 365 OP DAYS /YR. 1993 ORE PRODUCED: 4,080,000 MTS CONTAINING 10,900 MT MO. 1994 RESERVES FROM CYPRUS-AMAX SEC FORM 10-K REPORT, 12/31/93, P. 7.

Workings at the site

  • Type of workings Underground
    Length 80465M
    Overall depth 944.88M

Comments on the workings information

  • PRINCIPAL MINE PRODUCTION ON 8100 (NOW EXHAUSTED) AND 7700 LEVELS; NEW PRODUCTION LEVEL IS 7225. NO. 1 AND NO. 3 SHAFTS (EXHAUST AND VENTILATION) ARE 1585 FT DEEP, 23 FT DIAMETER. NO. 2 SHAFT (MEN AND MATERIALS) IS 3100 FT DEEP AND 28 FT IN DIAMETER, THE LARGEST SUCH SHAFT IN NORTH AMERICA. LOWERMOST OR HAULAGE LEVEL WAS 9.6-MILE-LONG UNDERGROUND RAILROAD TUNNEL CONTINUING ONTO 4.8 MILES OF SURFACE RAILROAD TERMINATING AT ORE PROCESSING PLANT ON EAST BRANCH TRIBUTARY OF WILLIAMS FORK ON WEST SIDE OF CONTINENTAL DIVIDE IN GRAND CO. RAILROAD HAULAGE SYSTEM REPLACED IN 2000 BY CONVEYOR SYSTEM ON THE 7065 LEVEL.
  • From deleted MAS record 0080190055:
    MAS Development Schedule #: 1
    Mining Record # : 1
    Status of Mining Method : ACTUAL
    Mining Method : BLOCK CAVING 10-79
    Swell Factor : .84
    Percent Waste Rock : 0
    Percent Recovery : 89
    Hardness of Rock : HARDROCK WITH LITTLE WATER
    Rock Characteristics : MULTIPLE SYSTEMS OF WEAKNESS PLANES
    Rock Support Chars. : SUPPORTING MAY BACK SLAB
    Mine Support Chars. : CHEMICAL COATING
    Number of Shafts : 4
    Length of Inclines (m) : 123
    Slope of Inclines : 8
    Number of Inclines : 5
    Avg. Length of Adits (m) : 15460
    Number of Adits : 1
    1st Condition of Workings : OPEN
    Capacity : 27200
    Capacity Units : MT ORE/DAY
    Unit Production Cost : 5.93
    Units of Production : $/MT ORE
    Operating Days per Year : 357
    Operating Shifts per Day : 3Y
    ear of Information : 1979

Comments on other economic factors

  • Copied from deleted record 0080190055:
    AT PRESENT(JULY,1979) THE MILL RECOVERY IS AVERAGING ABOUT 86 PERCENT WHICH IS WELL BELOW THE EXPECTED 90 PERCENT. AN INCREASED RECOVERY IS EXPECTED WHEN THE FOURTH SEMI-AUTOGENOUS MILL COMES ON LINE. THE AVERAGE RECOVERY FOR THE LIFE OF THE PROPERTY IS 90 PERCENT.

Comments on development

  • DURING THE 1980'S WHEN MOLYBDENUM PRICES FELL DRAMATICALLY, MINE AND MILL EMPLOYEES CUT PRODUCTION COSTS BY MORE THAN 50% AND TRIPLED PRODUCTIVITY BY EMPLOYING HIGHLY MECHANIZED MINE AND MILL EQUIPMENT. A $5 MILLION MODERNIZATION OF THE MILL THROUGH COMPUTERIZATION INCREASED THE LIFE OF THE EQUIPMENT AND LOWERED POWER DEMAND AND ASSOCIATED COSTS. THE COMPANY'S OUTPUT IN 1989 WAS ESTIMATED TO TOTAL 46 MILLION LB. CLIMAX MOLYBDENUM COMPANY CUT PRODUCTION BY 15 PERCENT BEGINNING 1/1/90. IN 1992 THE COMPLEX EMPLOYS ABOUT 500 PEOPLE DOWN FROM THE 2,000 EMPLOYED DURING PEAK OPERATIONG YEARS, BUT UP FROM A LOW OF 43 WORKERS IN 1983 WHEN THE MINE WAS CLOSED BECAUSE OF AN OVERSUPPLY, EXCESS STOCKPILES, AND LOW PRICES. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT
  • Copied from Deleted record 0080190055:
    ORE IS TRANSPORTED FROM THE MINE TO THE MILL BY ELECTRIC TRAIN AND BOTTOM DUMP ORE CARS. THE TRAIN TRAVELS 9.6 MILES THROUGH TUNNEL AND 4.8 MILES OF OPEN RAILROAD. TOTAL DISTANCE IS 14.4 MILES. THE MINSIM FILE SHOWS A MINE OP COST INCREASE. THIS INCREASE IS THE RAILROAD OP COST INCREASE BECAUSE THE R.R. EQUIPMENT WILL NOT BE REINVESTED. THIS PROPERTY REVIEWED BY RC SMITH, 4-87. AT THIS TIME, THERE HAVE BEEN NO SIGNIFICANT CHANGES TO THE MINE AND MILL. PRODUCTION HAS BEEN AT REDUCED CAPACITY FOR THE LAST FEW YEARS THROUGH TEMP SHUTDOWNS AND MODIFIED WORK SCHEDULES.
  • EDGE OF ORE BODY INTERSECTED IN LAST HOLE OF DEEP DRILLING EXPLORATION PROGRAM AT URAD MINE IN 1964. DEVELOPMENT BEGAN IN 1968; PRODUCTION BEGAN 1976. ; ECON.COM: HAS PRODUCED A TOTAL OF 100 MILLION TONS OF MOLYBDENUM ORE SINCE OPENING IN 1976. A NEW PRODUCTION LEVEL HAS BEEN DEVELOPED AT A COST OF $25 MILLION AND SHOULD PROVIDE AN ADDITIONAL 15 YEARS OF MINE LIFE. (PETERSON,1992)

Reference information

Bibliographic references

Comments on the references

  • From reference in deleted record 0080190055 (newMRDS 10190619):
    INFORMATION SOURCE: E.R.D.A. PRINT OUT OF OPEN FILE DATA $400 MILLION IN DEVELOPMENT, JAN 1976 P 92-98.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-81 Schwochow, Stephen D. Colorado Geological Survey
Updater 01-OCT-90 Berger, Mary A. U.S. Geological Survey
Updater 01-FEB-93 Moyer, Lorre A. (Marcus, S.M.) U.S. Geological Survey
Updater 24-MAY-06 Beach, Richard A. Colorado Geological Survey
Updater 03-AUG-07 Melton, Greg U.S. Geological Survey
Reporter 11-MAY-11 Heran, William D. U.S. Geological Survey Improved record for Nat'l Assessment Significant Deposits.
Editor 15-JUN-11 Wilson, Anna B. U.S. Geological Survey MAS 0080190055 = newMRDS 10190619, merged and deleted.
Reporter 26-AUG-97 Smith/West U.S. Bureau of Mines MAS 0080190055 = newMRDS 10190619

Beyond USGS

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

Current status (per MSHA)

StatusActive since 02/15/1973
MSHA mine ID0500790
Mine name (MSHA)HENDERSON OPERATIONS
Current operatorClimax Molybdenum Company
Current controller (parent)Freeport-McMoRan Inc
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:

  • Cyprus-Amax Minerals Co. — now part of Subsidiary of Freeport-McMoRan (2007)
    Formed by merger of Cyprus Minerals and AMAX in 1993; acquired by Phelps Dodge in 1999; Phelps Dodge acquired by Freeport-McMoRan in 2007.

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.

External references

Maps centered on this site

Authoritative Colorado resources

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