| Deposit ID | 10042346 |
|---|---|
| MRDS ID | M060101 |
| Record type | Site |
| Current site name | Benbow Mine |
| Geographic coordinates: | -109.8069, 45.36436 (WGS84) |
|---|---|
| Elevation | 2576 |
| Relative position | 42 MI FROM COLUMBUS; 9 MI FROM DEAN; 34 MI SOUTHEAST OF BIG TIMBER |
Political divisions (FIPS codes)
Stillwater(county)
Montana(state)
United States(country)
North America(continent)
Land(continent)
USGS map quadrangles
Mount Wood(quadrangle 1:24,000 scale)
Red Lodge(quadrangle 1:100,000 scale)
Billings(quadrangle 1:250,000 scale)
Hydrologic units (watersheds)
Stillwater(hydrologic unit)
Upper Yellowstone(hydrologic accounting unit)
Upper Yellowstone(hydrologic subregion)
Missouri(hydrologic region)
Federal lands
Custer Gallatin National Forest(National Forest)
National Forest FS(Type of land area)
FS(Federal land areas administered by FS)
| Country | State | County |
|---|---|---|
| United States | Montana | Stillwater |
| Meridian | Township | Range | Section | Fraction | State |
|---|---|---|---|---|---|
| Montana Principal | 005S;005S | 015E;016E | 25;28,29,30,31 | Montana |
| Commodity | Importance |
|---|---|
| Chromium Critical | Primary |
| Platinum Critical | Tertiary |
| Palladium Critical | Tertiary |
| Rhodium Critical | Tertiary |
| Materials | Type of material |
|---|---|
| Chromite | Ore |
| Olivine | Gangue |
| Serpentine | Gangue |
| Result | 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 |
|---|
| Model code | 2 |
|---|---|
| USGS model code | 2a |
| Deposit model name | Bushveld Cr |
| Host or associated | Associated | ||||||
|---|---|---|---|---|---|---|---|
| Rock type | Plutonic Rock > Granitoid > Quartz Monzonite | ||||||
| |||||||
| Host or associated | Associated |
|---|---|
| Rock type | Plutonic Rock > Mafic Intrusive Rock |
| Rock unit name | Stillwater Complex, Ultramafic Series |
| Rock description | Stillwater Complex, Ultramafic Series |
| Host or associated | Host |
|---|---|
| Rock type | Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Harzburgite |
| (1) | -109.8069, 45.36436 |
|---|
| Type of structure | Regional |
|---|---|
| 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 of structure | Local |
| Structure description | Numerous Small Faults Striking Northward |
| General form | MASSIVE BANDS AND DISSEMINATED |
|---|---|
| Strike | APPROX N65W |
| Dip | APPROX 80-VERT |
| Thickness | 2.44M |
| Length | 2743.2M |
| Depth to top | 0M |
| Development status | Past Producer |
|---|---|
| Commodity type | Metallic |
| Deposit size | Medium |
| Significant | No |
| Discovery year | 1905 |
| Year of first production | 1941 |
| District name | In Stillwater Complex |
|---|
| Ownership category | National Forest |
|---|
| Type | Owner-Operator |
|---|---|
| Owner | Anaconda Co. |
| First year | 1985 |
| Type of workings | Underground |
|---|---|
| Length | 14260.68M |
| Overall depth | 182.88M |
| Agency | Database name | Acronym | Record ID | Notes |
|---|---|---|---|---|
| USGS | Mineral Resources Data System | MRDS | M060101 | |
| USGS | International Strategic Minerals Inventory | ISMI | CR056 | |
| U.S. Bureau of Mines | Minerals Availability System | MAS | 0300950004 |
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.
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.
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.
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.
1939 DIREXPL USB
PAGE AND OTHERS, 1972
| Subject category | Comment text |
|---|---|
| Deposit | 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. |
| Deposit | THE LARGEST POTENTIAL RESOURCES OF CHROMIUM AND PGE IN THE U.S. ARE IN THE STILLWATER COMPLEX. ; INFO.SRC : 1 PUB LIT |
| Deposit | RECORD W026522 HAS BEEN MERGED AND DELETED. |
| Type | Date | Name | Affiliation | Comment |
|---|---|---|---|---|
| Reporter | 01-JAN-1973 | Dohrenwend, John C. | U.S. Geological Survey | |
| Updater | 01-JUN-1977 | Berg, Richard B. (Krohn, D. H.) | U.S. Geological Survey | |
| Updater | 01-AUG-1991 | Peterson, Jocelyn A. | U.S. Geological Survey |
Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.
MRDS records operators as of each record's last update (≤ 2019). Some of the operators listed here have since changed hands or dissolved:
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.