Henderson Mine

Site Name

Primary: Henderson Mine

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Commodity

Primary: Molybdenum
Secondary: Tungsten
Secondary: Lead
Secondary: Tin
Tertiary: Zinc
Tertiary: Iron

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Location

State: Colorado
County: Clear Creek
District: Henderson/Urad

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Land Status

Land ownership: Private
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: Patented
Type: Fee Ownership
Type: Private Lease

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Workings

Type: Underground

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Ownership

Owner Name: Climax Molybdenum Co., Division Of American Metal Climax Inc. (Amax)
Years: 1981 -

Owner Name: Freeport-McMoRan Copper and Gold Inc
Percent: 100.0
Home Office: 333 North Central Ave Phoenix AZ 85004 United States
Info Year: 2011
Years: 2007 -

Owner Name: Cyprus-Amax Minerals Co.
Percent: 100.0
Info Year: 1994
Years: 1994 -

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Production

Year: 1982
Mined: 3494000.000 mt
Year: 1981
Mined: 8833000.000 mt
Year: 1980
Mined: 9369000.000 mt
Year: 1979
Mined: 8411000.000 mt

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Deposit

Record Type: Deposit
Operation Category: Producer
Deposit Type: Climax Mo
Operation Type: Underground
Mining Method: Caving Methods - Block Caving
Milling Method: Flotation
Year First Production: 1976
Discovery Year: 1965
Discovery Method: Other
Years of Production:
Organization:
Significant: Y
Deposit Size: L

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Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

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Mineral Deposit Model

Model Name: Climax Mo

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Orebody

Form: ELLIPTICAL IN PLAN, UMBRELLA SHAPED IN PROFILE

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Structure

Type: R
Description: Front Range Uplift, Silver Plume Batholith, Colorado Mineral Belt

Type: L
Description: Straight Cr., Vasquez Cr., Loveland Pass-Berthoud Pass Fault Zones

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Alterations

Alteration Type: L
Alteration Text: Argillic Griesen Below Ore Body. Quartz, Quartz-Topaz-Magnetite, Quartz-Sericite-Pyrite, Argillic, And Propylitic Zones Progressively Above Ore Body

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Rocks

Name: Granite
Role: Host
Age Type: Host Rock
Age Young: Oligocene

Name: Granitoid
Role: Host
Age Type: Host Rock
Age Young: Oligocene

Name: Granitoid
Role: Host
Age Type: Host Rock
Age Young: Oligocene

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Analytical Data

Analytical Data: HIGH-GRADE ASSAY G.T. 0.8 % MOS2
Analytical Data: AVG. 0.49 % MOS2

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Materials

Ore: Molybdenite
Gangue: Topaz
Gangue: Sphalerite
Gangue: Sericite
Gangue: Quartz
Gangue: Pyrite
Gangue: Magnetite
Gangue: Huebnerite
Gangue: Hematite
Gangue: Galena
Gangue: Fluorite
Gangue: Rhodochrosite

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Comments

Comment (Reserve-Resource): FIRST EST. FROM TERRY FITZSIMONS, AMAX, 1980 PERS. COMM.; SECOND EST. FROM 1980 AMAX ANNUAL REPORT

Comment (Production): 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)

Comment (Reference): 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.

Comment (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;

Comment (Reserve-Resource): At the end of 2005, reserves were 150.7 million tons at a grade of 0.21% molybdenum. (Phelps Dodge 2005 Annual Report)

Comment (Workings): 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.

Comment (Development): 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)

Comment (Reserve-Resource): 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.

Comment (Reserve-Resource): 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.

Comment (Workings): 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

Comment (Reserve-Resource): 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.

Comment (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.

Comment (Geology): 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.

Comment (Development): 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.

Comment (Location): 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)

Comment (Identification): *****SEE RELATED DEPOSIT Urad Deposit ID 10012413

Comment (Geology): 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)

Comment (Geology): 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

Comment (Geology): 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)

Comment (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

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References

Reference (Production): Freeport Press release or Quarterly report YRS 2007-2010

Reference (Production): AMAX Annual Reports or 10K YRS 85-92

Reference (Deposit): E/MJ. MAINTENANCE PROGRAM FOR MOBILE EQUIPMENT CUTS COSTS AT HENDERSON MOLY MINE, MAY 1978 .

Reference (Deposit): MINING MAGAZINE. HENDERSON-ON STREAM. JAN 1977. VOL. 136. NO. 1. P. 10-23.

Reference (Production): Cyprus Amax Press release or 10K YRS 93-98

Reference (Production): Phelps Dodge 10K or Annual Reports YRS 99-2006

Reference (Reserve-Resource): Freeport-McMoRan Copper 10K 2/25/11

Reference (Deposit): AMAX, (NO DATE), HENDERSON: CLIMAX MOLYBDENUM CO. BROCHURE, 25 P.

Reference (Production): COLO. DIV. MINES ANN. OPERATOR REPTS.

Reference (Geology): Carten, R.B., Walker, B.M., Geraghty, E.P., and Gunow, A.J.,1988a, Comparison of field-based studies of the Henderson porphyry molybdenum deposit, Colorado, with experimental and theoretical models of porphyry systems: Canadian Institute of Mining and Metallurgy Special Volume 39, p. 351?366

Reference (Geology): White, W.H.,Bookstrom, A.A., Kamilli, R.J., Ganster, M.W., Smith, R.P., Ranta, D.E., and Steininger, R.C., 1981, Character and Orgin of Climax-type Molybdenum Deposits: in Economic geology; Seventy-fifth anniversary volume; 1905-1980, pgs 270-316

Reference (Deposit): BROWN L.F. RECLAMATION AT CLIMAX, URAD AND HENDERSON MINE. MINING CONGRESS JOURNAL, APRIL 1976.

Reference (Deposit): SKILLING'S MINING REVIEW. HAULAGE TUNNEL HOLED THROUGH AT AMAX'S HENDERSON MINE AUGUST 2 1975 P 10-11.

Reference (Deposit): COLORADO DIV. MINES ANN. OPERATOR REPTS.

Reference (Deposit): WALLACE, S.R., AND OTHERS, 1978, GEOLOGY OF THE URAD AND HENDERSON MOLYBDENITE DEPOSITS, CLEAR CREEK COUNTY, COLORADO, WITH A SECTION ON A COMPARISON OF THESE DEPOSITS WITH THOSE AT CLIMAX, COLORADO: ECON. GEOLOGY, V. 73, P. 325-368.

Reference (Deposit): DESBOROUGH, G.A., AND MIHALIK, PETER, 1980, ACCESSORY MINERALS IN THE IGNEOUS HOST OF MOLYBDENUM ORE, HENDERSON MINE, COLORADO: USGS OPEN-FILE REPT 80-661, 16 P.

Reference (Geology): Seedorf, E., and Einaudi, M. T., 2004, Henderson porphyry molybdenum system, Colorado, Part I: Economic Geology, v. 99, p.3-37; Part II: Economic Geology, v. 99, p. 39-72.

Reference (Deposit): WORLD MINING. HOW TO SINK VENT SHAFT IN REMOTE AREAS USING HELICOPTER SUPPORT. JULY 1975. P 30-35.

Reference (Deposit): PETERSON, EILEEN K., 1992, USBM MINERALS TODAY OCT. 1992, P.30.

Reference (Deposit): E/MJ. HENDERSON: A 15-MILE SHOWCASE FOR MINING, RAILROADING AND PROCESSING, 1969

Reference (Reserve-Resource): PERSONNEL CONTACT, MARCH 96.

Reference (Deposit): THE HENDERSON MINE (MILL) CONCENTRATOR: JOUR. METALS, V. 29, NO. 10 (OCTOBER 1977), P. 9-12.

Reference (Deposit): JOURNAL OF METALS. THE HENDERSON MINE/MILL/CONCENTRATOR. OCT 1977

Reference (Deposit): MINING MAGAZINE. THE HENDERSON PROJECT. AUG 1975

Reference (Deposit): BUSINESS WEEK. A CLEVER ORE TRAIN THAT WORKS. JULY 1976

Reference (Deposit): RAILWAY TRACK AND STRUCTURES. ISOLATED MINING LINE HAS BIG RAILROAD FEATURES, SEPT 1975

Reference (Deposit): CYPRUS AMAX MINERALS CO., FORM 10-K RPT, 12/31/93, P 7.

Reference (Deposit): NICKEL NEWS. ISSUE 32/52. 8/6/97. P.12.

Reference (Geology): Carten, R.B., Geraghty, E.P., Walker, B.M., and Shannon, J.R., 1988, Cyclic development of igneous features and their relationship to high-temperature hydrothermal features in the Henderson porphyry molybdenum deposit, Colorado: Economic Geology, v. 83, p. 266-296

Reference (Production): Freeport-McMoRan Copper Press release 2010

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