Benbow Mine

  

Mine Info

State: Montana

County: Stillwater

Elevation: 8,451 feet (2,576 meters)

Primary Mineral: Chromium

Lat, Long: 45.36444, -109.80611



Benbow Mine MRDS details

Site Name

Commodity

Location

Primary: "Benbow Mine"
Primary: Chromium
Tertiary: Platinum
Tertiary: Palladium
Tertiary: Rhodium
State: Montana
County: Stillwater
District: In Stillwater Complex
 

Land Status

Holdings

Workings

Land ownership: National Forest
Administrative Organization:
Type: Underground


Ownership

Production

Deposit

Owner Name: Anaconda Co.
Company ID:
Percent:
Home Office:
Info Year:
Years: 1985 -

Record Type: Site
Operation Category: Past Producer
Deposit Type:
Plant Type:
Plant Subtype:
Operation Type: Unknown
Mining Method:
Milling Method:
Year First Production: 1941
Year Last Production:
Discovery Year: 1905
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: M


Physiography

Mineral Deposit Model

Orebody

General Physiographic Area: Rocky Mountain System
Physiographic Province: Middle Rocky Mountains
Physiographic Section:
Physiographic Detail: East Flank Of Beartooth Mountains
Name:
Form: MASSIVE BANDS AND DISSEMINATED


Structure

Alterations

Rocks

Type: R
Structure:
Description: The Stillwater Complex Is Exposed Along The Northern Margin Of The Beartooth Uplift, One Of Several Laramide Basement-Cored Ranges That Make Up The Rocky Mountain Foreland Of South-Central Montana (Foose And Others, 1961: Kulik And Schmidt, 1988) ; Reg.Trends: Strike Of Ultramafic Zone: N60 Deg. W-N 80 Deg.W
Type: L
Structure:
Description: Numerous Small Faults Striking Northward
Alteration Type: L
Alteration:
Alteration Text: Some Serpentinization Of Harzburgite
Name: Quartz Monzonite
Role: Associated
Description:
Age Type: Associated Rock
Age in Years:
Dating Method:
Material Analyzed:
Age Young: Early Cretaceous
Age Old:
Name: Quartz Monzonite
Role: Associated
Description:
Age Type: Associated Rock Unit
Age in Years:
Dating Method:
Material Analyzed:
Age Young: Neoarchean
Age Old:
Name: Quartz Monzonite
Role: Associated
Description:
Age Type: Host Rock
Age in Years:
Dating Method:
Material Analyzed:
Age Young: Early Cretaceous
Age Old:


Analytical Data

Materials

Analytical Data : AVERAGE CR2O3 CONTENT: 24.5%. DIAMOND DRILL HOLE DATA (17 HOLES) YIELDED 21.6-36% CR203 OVER 4-9 FT WIDTHS. AVERAGE OF CHROMITITES: 89.9 PPB PT, 81.8 PPB PD, 52.1 PPB RH (MAX.: 330 PPB PT, 270 PPB PD, 190 PPB RH). ANALYSIS OF CLEANED SAMPLE: 24.05% FEO, 46.09% CR2O3, 23.81% AL2O3, 5.43% MGO, 1.02% SIO2. AVERAGE CR:FE=1.46 IN MASSIVE ORE
Ore: Chromite
Gangue: Olivine
Gangue: Serpentine


Comments

Comment Type:
Location
Comment UNSURVEYED. LOCATION GIVEN IS FOR SHAFT SYMBOL ON MAP. DEPOSIT EXTENDS ACROSS LITTLE ROCKY CREEK. LOCATED NEAR EAST END OF STILLWATER COMPLEX. IN CUSTER NATIONAL FOREST
Comment Type:
Production
Comment PRODUCTION DURING WWII FROM BENBOW+MOUAT-SAMPSON WAS 364,196 LT MINED, 237,771 LT MILLED, 91,164 LT CONCENTRATES
Comment Type:
Geology
Comment AGE OF STILLWATER COMPLEX IS 2,705 +/- 4 MA BASED ON U-PB SYSTEMATICS ON ZIRCON-BADDELEYITE (PREMO AND OTHERS, 1990) ; GEOL.DESC: AGE OF HOST ROCKS:PRE-CAMBRIAN; MAJOR.UNITS: STILLWATER COMPLEX.
Comment Type:
Deposit
Comment THE LARGEST POTENTIAL RESOURCES OF CHROMIUM AND PGE IN THE U.S. ARE IN THE STILLWATER COMPLEX. ; INFO.SRC : 1 PUB LIT
Comment Type:
Deposit
Comment RECORD W026522 HAS BEEN MERGED AND DELETED.
Comment Type:
Workings
Comment ADITS, MORE THAN 100 TRENCHES, 2,638 FT DIAMOND DRILL HOLES
Comment Type:
Development
Comment PROPERTY WAS WORKED DURING WWI BUT NO SHIPMENTS WERE MADE ; TOTAL$: 4 ; DEV$: 0.701 ; ECON.YEAR: 1943 ; ECON.COM: 1941-1943 FINANCED BY RECONSTRUCTION FINANCE CORP. ; MILL.CAP : 182 ST
Comment Type:
Reserve-Resource
Comment RESOURCE POTENTIAL IS FOR AREA BETWEEN BENBOW AND MOUAT-SAMPSON AT A DEPTH OF LESS THAN 2,000 FT. IDENTIFIED RESOURCES OF MOUAT-SAMPSON+BENBOW ARE 15 MILLION TONS AT 20-22% CR2O3
Comment Type:
Deposit
Comment THE AVERAGE THICKNESS OF THE DEPOSIT IS 4.9 FT AT 24.5% CR2O3. G CHROMITITE ZONE HAS BEEN MINED. OVERLAPPING LENSES WITH DISSEMINATED ORE BETWEEN. THERE ARE MANY SMALL RIGHT-LATERAL OFFSETS IN THE MAIN CHROMITITE BAND ALONG NORTH TRENDING FAULTS. DEPOSIT IS CUT BY SEVERAL LARGE DIABASE DIKES. MASSIVE+DISSEMINATED ORE IS 50 FT WIDE MAX.
Comment Type:
Reserve-Resource
Comment JACKSON ESTIMATED TOTAL CHROMITE RESERVES OF STILLWATER COMPLEX TO BE 2,520,000 LONG TONS CR2O3


References

Reference Category:
Deposit
Pages:
Reference: ZIENTEK, M.L., 1993, MINERAL RESOURCE APPRAISAL FOR LOCATABLE MINERALS: THE STILLWATER COMPLEX, IN HAMMARSTROM, J.M., ZIENTEK, M.L., AND ELLIOTT, J.E., EDS., MINERAL RESOURCE ASSESSMENT OF THE ABSAROKA-BEARTOOTH STUDY AREA, CUSTER AND GALLATIN NATIONAL FORESTS, MONTANA: U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 93-207, P. F1-F83.
URL:
Reference Category:
Deposit
Pages:
Reference: PAGE, N.J, AND DOHRENWEND, J.C., 1973, MINERAL RESOURCE POTENTIAL OF THE STILLWATER COMPLEX AND ADJACENT ROCKS IN THE NORTHERN PART OF THE MOUNT WOOD AND MOUNT DOUGLAS QUADRANGLES, SOUTHWESTERN MONTANA: U.S. GEOLOGICAL SURVY CIRCULAR 684, 9 P.
URL:
Reference Category:
Deposit
Pages:
Reference: PREMO, W.R., HELZ, R.T., ZIENTEK, M.L., AND LANGSTON, R.B., 1990, U-PB AND SM-ND AGES FOR THE STILLWATER COMPLEX AND ITS ASSOCIATED SILLS AND DIKES, BEARTOOTH MOUNTAINS, MONTANA: IDENTIFICATION OF A PARENT MAGMA?: GEOLOGY, V. 18, P. 1065-1068.
URL:
Reference Category:
Deposit
Pages:
Reference: 1939 DIREXPL USB
URL:
Reference Category:
Reserve-Resource
Pages:
Reference: PAGE AND OTHERS, 1972
URL:
Reference Category:
Deposit
Pages:
Reference: PAGE, N.J, RILEY, L.B., AND HAFFTY, JOSEPH, 1969, PLATINUM, PALLADIUM, AND RHODIUM ANALYSES OF ULTRAMAFIC AND MAFIC ROCKS FROM THE STILLWATER COMPLEX, NMONTANA: U.S. GEOLOGICAL SURVEY CIRCULAR 624, 12 P.
URL:
Reference Category:
Deposit
Pages:
Reference: PAGE, N.J, RILEY, L.B., AND HAFFTY, JOSEPH, 1972, VERTICAL AND LATERAL VARIATION OF PLATINUM, PALLADIUM, AND RHODIUM IN THE STILLWATER COMPLEX, MONTANA: ECONOMIC GEOLOGY, V. 67, P. 918.
URL:
Reference Category:
Deposit
Pages:
Reference: WIMMLER, N.L., 1948, INVESTIGATION OF CHROMITE DEPOSITS OF THE STILLWATER COMPLEX, STILLWATER AND SWEETGRASS COUNTIES, MONT.: U.S. BUREAU OF MINES REPORT OF INVESTIGATIONS 4368, P. 16-19.
URL:
Reference Category:
Deposit
Pages:
Reference: PEOPLES, J.W., AND HOWLAND, A.L., 1940, CHROMITE DEPOSITS OF THE EASTERN PART OF THE STILLWATER COMPLEX, STILLWATER COUNTY, MONTANA: U.S. GEOLOGICAL SURVEY BULLETIN 922-N, P. 371-411.
URL:
Reference Category:
Deposit
Pages:
Reference: JACKSON, E.D., 1968, THE CHROMITE DEPOSITS OF THE STILLWATER COMPLEX, MONTANA, IN RIDGE, J.D., ED., ORE DEPOSITS OF THE UNITED STATES,1933/1967, GRATON-SALES VOLUME: NEW YORK, AMERICAN INSTITUTE OF MINING, METALLURGICAL, AND PETROLEUM ENGINEERS, P. 1495-1510.
URL:

Did You Know.......

A mine is a hole in the ground, owned by a liar.
-Mark Twain

About The MRDS Mines Database

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Search

Recent Posts


Popular Tags

1906 San Francisco Earthquake Best Historical Photos Best Of Mining Era Structures Cemeteries Churches Gambling Towns Headframes Historical Commercial Buildings Historical Homes Hotels Mining Machinery Smelters Stamp Mills Victorian Homes Winter Scenes View All Tags