Last Chance Prospect

The Last Chance Prospect is a thorium and copper mine located in Lemhi county, Idaho at an elevation of 4,501 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: Last Chance Prospect  

State:  Idaho

County:  Lemhi

Elevation: 4,501 Feet (1,372 Meters)

Commodity: Thorium, Copper

Lat, Long: 45.3961, -114.07330

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 Last Chance Prospect

Last Chance Prospect MRDS details

Site Name

Primary: Last Chance Prospect


Commodity

Primary: Thorium
Primary: Copper
Secondary: REE
Tertiary: Titanium


Location

State: Idaho
County: Lemhi
District: Indian Creek 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.
Administrative Organization: Salmon National Forest


Holdings

Not available


Workings

Not available


Ownership

Owner Name: C. E. Brown, Ralph Malloy


Production

Not available


Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Surface
Years of Production:
Organization:
Significant: N
Deposit Size: S


Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Northern Rocky Mountains
Physiographic Detail: Salmon River Mountains


Mineral Deposit Model

Not available


Orebody

Form: THIN SEAMS, PODS, BUNCHLIKE CLUSTERS, STREAKS


Structure

Type: L
Description: Weak Foliation


Alterations

Alteration Type: L
Alteration Text: Gouge, Epidote, Clinozoisite, Chlorite, Sericite


Rocks

Name: Amphibolite
Role: Associated
Age Type: Associated Rock
Age Young: Neoproterozoic

Name: Amphibolite
Role: Associated
Age Type: Host Rock
Age Young: Neoproterozoic

Name: Amphibolite
Role: Associated
Age Type: Host Rock Unit
Age Young: Neoproterozoic


Analytical Data

Not available


Materials

Ore: Monazite
Ore: Rutile
Ore: Ilmenite
Ore: Xenotime
Ore: Chalcopyrite
Ore: Allanite
Gangue: Apatite
Gangue: Labradorite
Gangue: Zircon
Gangue: Albite
Gangue: Tourmaline
Gangue: Calcite
Gangue: Quartz
Gangue: Biotite
Gangue: Magnetite


Comments

Comment (Deposit): SW of deposit described above is small monazite occurrence which strikes N 20 Deg W, Dips 70 Deg SW, found in sandstone - like rock in schist

Comment (Deposit): Author Anderson states 2 contrasting, unrelated types of mineralization, shear zones and pegmatites in part in amphibolized gabbroic rock and in part in schistose and gneissic rocks.

Comment (Location): On upper canyon slope of Salmon River across from mouth of Dump Creek

Comment (Commodity): Spotty radioactivity over monazite; Allanite has high radioactivity

Comment (Development): 12 claims in group


References

Reference (Deposit): Anderson, A. L., 1958, Uranium, Thorium, Columbium, And Rare Earth Deposits In The Salmon Region, Lemhi County, Idaho: Idaho Bureau Of Mines And Geology Pamphlet 115, 81 P

Reference (Deposit): USBM WFOC Wilderness Studies


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