The Maginnis Mine is a gold mine located in Fergus county, Montana at an elevation of 5,026 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: 5,026 Feet (1,532 Meters)
Commodity: Gold
Lat, Long: 47.17667, -109.21889
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.
Mine Description
A 1500 foot decline driven between 1987 and 1990, intersected the lowest working of the old mine. Fifty five tons of ore were extracted from just below the old working. This averaged 2.5 oz/T Au and 3.0 oz/ton Ag. An exploratory underground drilling program was planned but halted when the operator experienced problems with their other Judith Mountain operations and forced to shut down. Jerry Hanley has the mine on care and maintenance with the intentions of initiating an exploration drilling program. Approximately 20,000 tons of old waste rock dumps contain 1,500 ounces of Au and 25,000 ounces of silver. The ten stamp mill built in 1884 still stands.
Information provided by Jerry Hanley
MRDS data below was updated with information provided by current mine owner Jerry Hanley. Fields updated: district, land status, ownership, mining methods, production (under deposit), milling method, year last production, years of production, discovery method.
Maginnis Mine MRDS details
Site Name
Primary: Maginnis Mine
Commodity
Primary: Gold
Secondary: Silver
Location
State: Montana
County: Fergus
District: Warm Springs District
Land Status
Land ownership: Patented, private property
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: Underground
Ownership
Owner Name: Jerry D. Hanley
Home Office: PO Box 851, Lewistown, MT 59457
Info Year: 2013
Production
Not available
Deposit
Record Type: Site
Operation Category: Past Producer
Deposit Type: Au-Ag-Te vein
Operation Type: Underground
Mining Method: Open stopes.
Milling Method: 1882-1883, Pan Amalgamation; 1884, 10 stamp amalgamation and vanners, 1900, cyanide circuit added. Mill last operated in 1922.
Year First Production: 1881
Year Last Production: 1991
Discovery Year: 1880
Discovery Method: Sinking and drifting on outcrop assaying over 30 oz/T Au.
Years of Production:
Organization:
Significant: Y
Deposit Size: S
Physiography
General Physiographic Area: Interior Plains
Physiographic Province: Great Plains Province
Physiographic Section: Missouri Plateau, Unglaciated
Physiographic Detail: Judith Mountains
Mineral Deposit Model
Model Name: Alkaline Au-Te (Au-Ag-Te veins)
Orebody
Not available
Structure
Type: R
Description: Domal Structures Resulting From Igneous Intrusions
Type: L
Description: Gold Hill Syenite Porphyry Intrusion
Alterations
Not available
Rocks
Name: Syenite
Role: Associated
Age Type: Host Rock Unit
Age Young: Mississippian
Name: Syenite
Role: Associated
Age Type: Associated Rock
Age Young: Pliocene
Name: Syenite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Pliocene
Analytical Data
Not available
Materials
Ore: Telluride
Ore: Argentite
Ore: Gold
Gangue: Calcite
Gangue: Fluorite
Comments
Comment (Workings): MINE WORKED THROUGH TWO ADITS, ONE ABOUT 300 FT LONG, THE OTHER ABOUT 1450 FT. A WINZE WITH SEVERAL LEVELS WAS SUNK FROM THE LOWER ADIT.
Comment (Geology): SPOTTED HORSE, MAGINNIS, AND CUMBERLAND ON GOLD HILL SYENITE PORPHYRY - MADISON LIMESTONE CONTACT
Comment (Deposit): Merged data fron Deposit ID 10196895 (Maginnis Mine)
References
Reference (Deposit): ROBERTSON, A. F., 1950, MINES AND MINERAL DEPOSITS, FERGUS COUNTY, MONT.: U.S. BUREAU OF MINES INF. CIRC. 754
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.
