Maginnis Mine

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

Name: Maginnis Mine  

State:  Montana

County:  Fergus

Gallery: View 1 Maginnis Mine Photos

Elevation: 5,026 Feet (1,532 Meters)

Primary Mineral: 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.


Satelite image of the Maginnis Mine

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