Mirror Harbor Copper-Nickel Prospect

The Mirror Harbor Copper-Nickel Prospect is a nickel and copper mine located in Alaska at an elevation of 10 feet.

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

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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: Mirror Harbor Copper-Nickel Prospect

Commodity

Primary: Nickel
Primary: Copper

Location

State: Alaska
District: Chichagof

Land Status

Land ownership: National Forest
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.

Holdings

Not available

Workings

Type: Surface

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Discovery Year: 1911
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

Not available

Mineral Deposit Model

Not available

Orebody

Form: POD

Structure

Not available

Alterations

Not available

Rocks

Name: Diorite
Role: Associated
Age Type: Associated Rock
Age Young: Late Cretaceous

Analytical Data

Analytical Data: AVERAGE OF 37 FT. OF ORE SAMPLES AT 75 FT. LEVEL DRIFT TAKEN IN 1917 IS 3.42% NI AND 1.58% CU, WITH MAXIMUM VALUES OF 5.70% NI AND 4.00% CU, ACCORDING TO USGS B 947-C, TABLE 17, NOS. 4-17. INDICATED AVERAGE GRADE OF DEPOSIT FROM DIAMOND DRILL HOLE CORES AND CHANNEL SAMPLES BY USBM IN 1942 IS 1.54% NI AND 0.78% CU, ACCORDING TO USGS B 947-C, P. 62.

Materials

Ore: Pentlandite
Ore: Chalcopyrite
Ore: Niccolite
Ore: Pyrrhotite
Gangue: Plagioclase
Gangue: Pyroxene

Comments

Comment (Reserve-Resource): GRADE IS AVERAGE OF 72.5 FT. OF DIAMOND DRILL HOLE CORE AND 29 FT. OF SURFACE CHANNEL SAMPLE. AVERAGE GRADE OF CORE ALONE IS 1.57% NI AND 0.88% CU.

Comment (Development): CLAIMS STAKED 1911, RELOCATED 1915. 180 FT. SHAFT SUNK IN 1917 BY ALASKA NICKEL MINES. EXTENSIVE DRILLING AND TRENCHING BY USBM IN 1942. NUMEROUS ACTIVE CLAIMS AS OF 1977-USBM OFR 20-73

Comment (Deposit): MAGMATIC SEGREGATIONS OF PYRRHOTITE, PENTLANDITE, CHALCOPYRITE, AND MINOR NICCOLITE OCCUR LARGELY AS SMALL PODS (UP TO 4 IN. BY 4 IN. BY 8 IN.) IN NEARLY BARREN NORITE BODY. NORITE ALSO CONTAINS LOW-GRADE DISSEMINATIONS OF SULFIDES. NORITE IS PART OF COMPOSITE STOCK AND IS IN CONTACT WITH DIORITE. SULFIDE-BEARING PORTION OF NORITE IS 40 FT. LONG AND 20 FT. WIDE AT SURFACE, AND EXTENDS TO AVERAGE DEPTH OF 110 FT. WHERE IT IS CUT OFF BY N 80 DEGREES E STRIKING, 75 DEGREES N DIPPING FAULT. MASSIVE SULFIDE-BEARING ORE IS FOUND AT THE 175 FT. LEVEL DRIFT IN SHAFT. DEPOSIT FORMS PIPE-SHAPED BODY PLUNGING 75 DEGREES SE, AND IS SURROUNDED BY BARREN NORITE NEAR DIORITE CONTACT.

Comment (Workings): 175 FT. SHAFT WITH 155 FT. OF DRIFTS AT 75 FT. AND 175 FT. LEVELS. SHAFT FLOODED AS OF 1942. 5 DIAMOND DRILL HOLES DRILLED BY USBM IN 1942, AS WELL AS SURFACE TRENCHES.

Comment (Location): USGS B 947-C, PL. 15, 16; USGS MF-467, LOC. 16. LOCATION AT SHAFT. LAND STATUS VALUE CALCULATED 6-94 USING GIS OVERLAY ANALYSIS WITH BLM 1:2,500,000 SCALE OWNERSHIP STATUS MAP (1991).

Comment (Geology): NORITE BODY IS PART OF COMPOSITE STOCK INTRUDED INTO METAMORPHOSED GRAYWACKE AND GREENSTONE. NORITE IS IN CONTACT WITH DIORITE.

Comment (Deposit): LUMPED INTO SAME DEPOSIT AS SI-17 AND SI-18 (DAVISON BAY) BY COBB IN MF-467, LOC. 16 AND OF 78-450, P. 82-84. NO PRODUCTION RECORDED, ALTHOUGH CONSIDERABLE AMOUNT OF ORE WAS MINED. ; INFO.SRC : 1 PUB LIT

Comment (Deposit): THIS SITE NAME WAS CREATED BY THE REPORTER OR OTHER USGS EMPLOYEE BASED ON PROXIMITY TO SOME MAJOR GEOGRAPHIC FEATURE.

References

Reference (Deposit): USGS B 947-C, P. 56-63, PLATES 15, 16 (1946)

Reference (Deposit): USGS B 936-I, P. 221-243 (1942)

Reference (Deposit): USGS MF-467, LOC. 16 (1972)

Reference (Deposit): USGS OF 78-450, P. 82-84 (1978)

Reference (Deposit): USBM OFR 20-73, LOC. 153B (1978)

Reference (Other Database): BAG-B-947-C-PL-15, 16

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