The Penobscot Mine is a silver and gold mine located in Lewis and Clark county, Montana at an elevation of 6,880 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
Elevation: 6,880 Feet (2,097 Meters)
Commodity: Silver, Gold
Lat, Long: 46.73056, -112.35611
Map: View on Google Maps
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.
Penobscot Mine MRDS details
Site Name
Primary: Penobscot Mine
Commodity
Primary: Silver
Primary: Gold
Location
State: Montana
County: Lewis and Clark
District: Marysville District
Land Status
Not available
Holdings
Not available
Workings
Type: Underground
Ownership
Owner Name: Longmaid, H. E.
Home Office: Helena, Montana
Production
Year: 1941
Time Period: 1890 - 1941
Material type: AU
Description: Cp_Grade: ^1 - 500 Oz/St
Year: 1945
Time Period: 1890-1945
Mined: 48000.000 mt
Material type: ore
Deposit
Record Type: Site
Operation Category: Past Producer
Deposit Type: Polymetallic veins
Operation Type: Unknown
Year First Production: 1878
Discovery Year: 1872
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: Y
Deposit Size: S
Physiography
General Physiographic Area: Rocky Mountain System
Physiographic Province: Northern Rocky Mountains
Mineral Deposit Model
Model Name: Polymetallic veins
Orebody
Form: PINCH AND SWELL
Structure
Type: R
Description: Boulder Batholith, Prickly Pear Dome
Type: L
Description: Marysville Stock, Post-Mineral Downthrown Fault Blocks
Alterations
Not available
Rocks
Name: Diorite
Role: Associated
Description: PORPHYRITIC DIORITE
Age Type: Associated Rock
Age Young: Pliocene
Name: Diorite
Role: Associated
Description: PORPHYRITIC DIORITE
Age Type: Host Rock
Age Young: Neoproterozoic
Name: Diorite
Role: Associated
Description: PORPHYRITIC DIORITE
Age Type: Host Rock Unit
Age Young: Neoproterozoic
Analytical Data
Not available
Materials
Ore: Gold
Ore: Quartz
Comments
Comment (Workings): INCLINE ON EAGLE VEIN; MAIN MINE EXTRACTED ORE FROM THE PENOBSCOT VEIN 1000 FT ALONG STRIKE; TUNNEL 300 FT LONG AND 90 FT DEEP; TUNNEL THAT WAS TO THE VEIN ON THE 300 FT LEVEL.
Comment (Deposit): 2 PARALLEL VEINS, EAGLE AND LENARD, LIE IN FOOTWALL OF PENOBSCOT VEIN AT 250 FT AND 600 FT RESPECTIVELY. ORE PRINCIPALLY FROM ABOVE 200 FT LEVEL.
Comment (Location): ALONG CONTINENTAL DIVIDE.
Comment (Production): PRODUCTION HAD REPORTED VALUE OF $1,250,000. PRODUCED ABOUT $50,000 1936-1941 . PRODUCTION YEARS ABOUT 1890 - 1900 , 1936 - 1941.
References
Reference (Deposit): USGS BULL 527, P. 74-5.
Reference (Deposit): USGS BULL 842, P. 63, PL. 5.
Reference (Deposit): AM INST MINING METALL ENGINEERS BULL 92, P. 2113-16.
Reference (Production): MCDERMOTT, 1914, A. I. M. M. E. BULL. 92.; MBMG MEM. 31, 1950
Principal Gold Districts of Montana
In Montana, 54 mining districts have each have produced more than 10,000 ounces of gold. The largest producers are Butte, Helena, Marysville, and Virginia City, each having produced more than one million ounces. Twenty seven other districts are each credited with between 100,000 and one million ounces of gold production. Read more: Principal Gold Districts of Montana.
