Borealis Mine

The Borealis Mine is a gold mine located in Mineral county, Nevada at an elevation of 7,241 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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Site Name

Primary: Borealis Mine

Commodity

Primary: Gold
Secondary: Silver
Tertiary: Copper
Tertiary: Zinc

Location

State: Nevada
County: Mineral
District: Lucky Boy District

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/Underground

Ownership

Owner Name: Echo Bay
Years: 1988 -

Production

Year: 1987
Time Period: 1981-1987
Material type: ORE AU
Description: Cp_Grade: ^0.12 Oz Au/Ton (From Peripheral Deposits)
Year: 1987
Time Period: 1981-1987
Material type: ORE AU
Description: Cp_Grade: ^0.12 Oz Au/Ton

Deposit

Record Type: Site
Operation Category: Producer
Operation Type: Unknown
Discovery Year: 1935
Years of Production:
Organization:
Significant: N
Deposit Size: M

Physiography

Not available

Mineral Deposit Model

Model Name: Hot-spring Au-Ag

Orebody

Not available

Structure

Type: R
Description: Reg.Struct: Maj. Reg. Trends (Walker Lane Shear Zone; Borealis Trend).

Type: L
Description: Ne-Trending Faults With Subordinate W-S And E-W Striking Structures.

Alterations

Alteration Type: L
Alteration Text: Pervasive Silicification, Alunitization, Kaolinization.

Rocks

Not available

Analytical Data

Analytical Data: VALUES OF 600 TO 1000 PPM FOR SB AND PB, 500 PPM AS AND OVER 5 PPM HG.
Analytical Data: 10-40 PPM AG AND CU
Analytical Data: 30-150 PPM AS, 3-5 PPM HG. PERIPHERAL ORE ZONEROCKS CONTAIN 3-10 PPM AU
Analytical Data: 40-80 PPM CU, PB AND SB
Analytical Data: 1-30PPM AG
Analytical Data: ORE AVERAGES 0.1 OZ/T AU AND 0.5 OZ/T AG. ORE-ZONE CONTAINS 1-3 PPM AU

Materials

Gangue: Kaolinite
Gangue: Pyrite
Gangue: Quartz
Gangue: Alunite
Gangue: Barite
Gangue: Hematite
Gangue: Montmorillonite

Comments

Comment (Deposit): OREBODY IS LOCALIZED SOUTH OF A SPORADICALLY MINERALIZED NE-TRENDING FAULT ZONE. PYROCLASTIC BRECCIA HOST IS PERVASIVELY SILICIFIED BY HYDROTHERMAL QUARTZ AND POTASSIUM FELDSPAR WITH ALUNITE AND BARITE. GOLD MINERALIZATION TERMINATES ABRUPTLY ALONG THE GENTLY NW-DIPPING CONTACT WITH UNDERLYING ANDESITIC FLOW ROCKS. A STRONGLY ACID-LEACHED ZONE HIGH IN AG VALVES IS DEVELOPED BELOW THIS CONTACT. THE INTENSELY BRECCIATED ACID-LEACHED ZONE CONTAINS PODS, STRINGERS AND STOCKWORK VEINLETS OF OXIDIZED QUARTZ-SULFIDE IN A POWDERY BLEACHED, SILICEOUS MATRIX. INTENSE ACID LEACHING (CHARACTERIZEDBY QUARTZ, TIOZ, CLINOCHLORE, BARITE, JAROSITE/ALUNITE) GRADES OUTWARD TO MODERATE ARGILLIC ALTERATION (KAOLIN, MONTMORILLONITE). NE-TRENDING SMALL MINERALIZED PODS ASSOCIATED WITH INTENSE ACID LEACHING OCCUR AS STRUCTURALLY CONTROLLED REPLACEMENTS UNDERNEATH AND TO THE SOUTH OFTHE MAIN ORE BODY. HOT SPRING VENT ORE.

Comment (Reserve-Resource): NBMG DISTRICT FILE 200, PRESS CLIPPINGS

Comment (Workings): OPEN PITS NOW, WITH OLDER UNDERGROUND WORKINGS

Comment (Geology): ALUNITE VEINING AT DEPTH.

Comment (Development): BOREALIS WAS MINED IN THE EARLY 1900'S AND INTERMITTENTLY THROUGH THE 1930'S. HOUSTON OIL AND MINERALS (LATER BOUGHT OUT BY TENNECO) ANNOUNCED PLANS FORTHE OPEN-PIT OPERATION IN 1980 AND BEGAN MINING IN 1981, CONTINUING THROUGH THE PRESSNT (1988). FIRST POUR WAS IN LATE 1981. ECHO BAY PURCHASED BOREALIS ALONG WITH MANHATTAN AND MCCOY FROM TENNECO IN 1986.

Comment (Production): SECOND PRODUCTION FIGURE IS FOR THE PERIPHERAL DEPOSITS AT JAIME'S RIDGE AND NORTH CERRO DURO.

Comment (Deposit): Discovery Year: 1930'S?

References

Reference (Deposit): REID, R. F., JR., 1984, THE GEOLOGY OF THE BOREALIS DEPOSIT: GSA ABSTRACTS WITH PROGRAMS, 97TH ANN MTG, RENO, NV.

Reference (Deposit): NBMG MINING DISTRICT FILE 200, ITEMS 8, 9, PRESS CLIPPINGS.

Reference (Deposit): TOOKER, E.W., 19?, IN USGS BULL 1646.

Reference (Deposit): STRACHAN, D.G., 19?, GEOLOGIC DISCUSSION OF THE BOREALIS GOLD DEPOSIT, MINERAL CO., NEVADA, IN USGS BULL 1646.

Reference (Deposit): BULK-MINEABLE PRECIOUS METALS SYMPOSIUM, 1987, FIELD TRIP GUIDEBOOK.

Reference (Deposit): NBMG, 1994, MI-1993

Reference (Production): GSN SYMPOSIUM FIELD TRIP GUIDEBOOK, 1987. NBMG MI-1993

Reference (Reserve-Resource): PRESS CLIPPINGS, NBMG FILE 200.

Nevada Gold

Nevada has a total of 368 distinct gold districts. Of the of those, just 36 are major producers with production and/or reserves of over 1,000,000 ounces, 49 have production and/or reserves of over 100,000 ounces, with the rest having less than 100,000 ounces. Read more: Gold Districts of Nevada.