Bernard Mountain Prospect

The Bernard Mountain Prospect is a chromium mine located in Alaska.

About the MRDS Data:

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.

Mine Info

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Bernard Mountain Prospect
Secondary: Red Mountain

Commodity

Primary: Chromium
Tertiary: Platinum
Tertiary: Nickel

Location

State: Alaska
District: Tonsina

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

Not available

Mineral Deposit Model

Not available

Orebody

Form: LENSE

Structure

Type: R
Description: Area Cut By Three Major Faults; Bernard Mt. Fault, Kimball Pass Fault And One Cross Fault

Alterations

Alteration Type: L
Alteration Text: Serpentinization Widespread In Ultramafices

Rocks

Not available

Analytical Data

Analytical Data: TABLE CONCENTRATES FROM COMPOSITE OF CUT SAMPLES CONTAINED 48% CHROMITE WITH CR: FE RATIO OF 2.7, USBM IC 8626, P. 18
Analytical Data: RANGE: 1500 PPM TO MORE THAN 5000 PPM CR, 1500 PPM TO 5000 PPM NI, MEAN: 5000 PPM CR, 2000 PPM NI, MAXIMUM PT CONCENTRATION .200 PPM, AVERAGE PT CONCENTRATION .023 PPM, HOFFMANN, BARRY, 1974, UNIV. OF ALASKA M. S. THESIS, P. 46, 50

Materials

Ore: Chromite

Comments

Comment (Commodity): ANOMALOUS IN PLATINUM GROUP ELEMENTS, NI AND CU

Comment (Location): LOCATION APPROXIMATED FROM USGS OFR 80-892B, LOC. 42

Comment (Geology): BERNARD MT. IS PART OF A SERPENTINIZED DUNITE SILL THAT EXTENDS DISCONTINUOUSLY OVER 12 MI BY 1.5 MI AREA THAT ROUGHLY PARALLES THE TRACE OF THE BERNARD MT. FAULT; DUNITE AND ASSOCIATED ULTRAMAFICS IN BERNARD MT. AREA ARE INTRUDED INTO ROCKS CORRELATIVE WITH STRELNA FORMATION; N OF BERNARD MT. ULTRAMAFIC BODY STRELNA FORMATION ROCKS ARE INTRUDED BY TWO SMALL BODIES OF AMPHIBOLITE AND GRANULITE GNEISS CUT BY APLITE DIKES; ROCKS OF STRELNA ARE METAMORPHOSED TO LOW GREENSCHIST FACIES. STREINA FM (MISS-PERM) IS SLATE AND PHYLLITE WITH MINOR GRAYWACKE, GREENSTONE, ARKOSIC SANDSTONE, MARBLE.

Comment (Deposit): DESPITE PROXIMITY TO RICHARDSON HIGHWAY, SUFFICIENT QUANTITIES OF ORE GRADE CHROMITE HAVE NOT BEEN PROVEN AND AREA REMAINS UNECONOMIC; MIGHT BE MINED UNDER VERY UNUSUAL ECONOMIC CONDITIONS; SEE ALSO: DUST MOUNTAIN, SHEEP MOUNTAIN ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Comment (Development): USGS BEGAN INVESTIGATING AREA IN EARLY 1930'S; MOST OF BERNARD MT.AREA STAKED FOR CHROMITE BY EARLY 1960'S; GEOLOGICAL, GEOCHEMICAL AND GEOPHYSICAL EXPLORATION MOSTLY AFTER 1960; ALSO SOME TRENCHING, STRIPPING AND SYSTEMATIC SAMPLING; CLAIMS RESTAKED IN 1966; 81 UNPATENTED CLAIMS HELD IN EARLY 70'S

Comment (Deposit): LAYERS, LENSES AND DISSEMINATIONS OF CHROMITE IN DUNITE AND ASSOCIATED ULTRAMAFICS; CHROMITE OCCURS AS DISSEMINATED GRAINS THAT FORM 0.5 TO 1% OF DUNITE, OR AS CONCENTRATIONS OF FROM 2 TO 40% CHROMITE IN TRAINS SEVERAL GRAINS WIDE, MASSIVE LENSES, OR LAYERS UP TO 6 IN THICK

References

Reference (Deposit): USBM IC 8626, P. 18

Reference (Deposit): HOFFMANN, BARRY, 1974, GEOLOGY OF THE BERNARD MOUNTAIN AREA, TONSINA, ALASKA: COLLEGE, ALASKA, UNIVERSITY OF ALASKA M. S. THESIS, 68 P.

Reference (Deposit): USGS OFR 78-1-E, P. 19

Reference (Deposit): USGS MF-438, LOC. 51

Reference (Deposit): USGS OFR 80-892B, LOC. 42

Reference (Other Database): BAG-OFR-80-892B-42

Reference (Deposit): USGS BULL 1246, P. 49, 52

Reference (Deposit): ADGGS GC 15, P. 2, 4

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