Grigg Group

The Grigg Group is a tungsten and silver mine located in Madison county, Montana at an elevation of 8,251 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

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.

Site Name

Primary: Grigg Group
Secondary: Wilson
Secondary: Roosevelt
Secondary: Grant
Secondary: Lincoln
Secondary: Washington
Secondary: Granite Mtn 1, 2 and 3 Claims

Commodity

Primary: Tungsten
Primary: Silver
Tertiary: Lead
Tertiary: Manganese
Tertiary: Gold
Tertiary: Molybdenum
Tertiary: Copper

Location

State: Montana
County: Madison
District: Potosi

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Owner Name: E. Roy Grigg

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Discovery Method: Unknown
Years of Production:
Organization:
Significant: N

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Northern Rocky Mountains
Physiographic Detail: Tobacco Root Mountains

Mineral Deposit Model

Not available

Orebody

Form: IRREGULAR

Structure

Type: R
Description: Tobacco Root Batholith

Type: L
Description: Nw-Trending Bismark Fault

Alterations

Not available

Rocks

Name: Quartz Monzonite
Role: Host
Age Type: Associated Rock Unit
Age Young: Late Cretaceous

Name: Quartz Monzonite
Role: Host
Age Type: Host Rock Unit
Age Young: Neoproterozoic

Analytical Data

Analytical Data: ASSAYS AVAILABLE FROM FOREST SERVICE

Materials

Ore: Tetrahedrite
Ore: Huebnerite
Gangue: Pyrite
Gangue: Galena
Gangue: Fluorite

Comments

Comment (Workings): CLAIM EXAMINED EARLIER BUT NO REPORT FOUND DISCOVERY CUT NO. 1 - DOZER CUT, 12 FT. W BY 6 - 8 FT. DEEP BY 130 FT. LONG. A HAND - DUG TRENCH CROSSES THE CENTRAL PORTION OF THE TRENCH (D. CUT), IT IS 2 - 4 FT. W. BY 3 FT. D. BY 15 FT. LONG; DEV. CUT NO. 2 5 - 8 FT. W. BY 3 - 15 FT. DEEP BY 30 FEET LONG.

Comment (Location): LOCATED ALONG SOUTH WILLOW CREEK BETWEEN POTOSI PEAK AND MINE PEAK.

Comment (Commodity): SAMPLES FROM DISCOVERY CUT NO. 1 AND DEVELOPMENT CUT NO. 2.

Comment (Deposit): STRIKES RANGE IN THE NORTHWEST N5-10E; AND IN THE SOUTH WEST N70E WITH DIPS 60-80 NW

Comment (Geology): TOBACCO ROOT BATHOLITH: THIS BATHOLITH HAS INTRUDED THE PRE - BELTIAN, PRECAMBRIAN METAMORPHIC ROCKS AND PALEOZOIC SEDIMENTARY ROCKS DURING LARAMIDE OROGENY. WHICH OCCURED IN THIS AREA DURING LATE CRETACEOUS OR EARLY EOCENE TIME. {{ SEDIMENTARY FORMATIONS: PLEISTOCENE MORAINE AND RECENT STREAM ALLUVIUM WHICH COVER THE CANYON FLOOR. {{ METAMORPHIC ROCKS: MADE UP OF THOUSANDS OF FEET OF DARK - COLORED GNEISSES AND SCHISTS BELONGING TO THE PONY SERIES OF PRECAMBRIAN AGE. {{ IGNEOUS ROCKS: THE TYPICAL IGNEOUS ROCKS ARE QUARTZ - MONZONITE COMPOSED OF ABOUT 20% QUARTZ, 30% ORTHOCLASE, 40% PLAGIOCLASE, FLEDSPARS, LESS THAN 3% BIOTITE, AND 1% HORNBLENDE. ACCESSORY MINERALS ARE ABOUT 2% SPHENE, 1% APATITE, AND 2% MAGNETITE AND SULFIDES (PYRITE).

References

Reference (Deposit): MBMG INF CIRC 21, P. 36.

Reference (Deposit): MBMG MEM 9, P. 32.

Reference (Deposit): CONSV. COMP DATE, 11-06-1963.

Reference (Deposit): 1933 RECON MBMG MEM 9

Reference (Deposit): 1961 DIREXPL USFS - CAN'T FIND REPORT

Reference (Deposit): 1968 DIREXPL USFS

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.