Northfield Prospect

The Northfield Prospect is a copper and cobalt mine located in Lemhi county, Idaho at an elevation of 7,300 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

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Site Name

Primary: Northfield Prospect
Secondary: Stevenson
Secondary: Merle 3 and 4

Commodity

Primary: Copper
Primary: Cobalt
Tertiary: Nickel

Location

State: Idaho
County: Lemhi
District: Blackbird Mining 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

Type: Surface/Underground

Ownership

Owner Name: Floyd And Merle Stevenson

Owner Name: Northfield Mines Inc.
Years: 1955 -

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Deposit Type: Blackbird Co Cu
Operation Type: Surface-Underground
Discovery Year: 1951
Discovery Method: Geophysical Anomaly
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: STRINGERS, IRREGULAR

Structure

Not available

Alterations

Alteration Type: L
Alteration: tourmalinization

Alteration Type: L
Alteration: limonitic
Alteration Text: Tourmaline, Iron Oxides

Rocks

Name: Quartzite
Role: Host
Age Type: Host Rock
Age Young: Mesoproterozoic
Age Old: Mesoproterozoic

Name: Quartzite
Role: Host
Age Type: Host Rock Unit
Age Young: Mesoproterozoic
Age Old: Mesoproterozoic

Analytical Data

Analytical Data: AVG. 0.468 % CO, 1.245 % C

Materials

Ore: Cobaltite
Ore: Chalcopyrite
Ore: Safflorite
Ore: Chalcocite
Ore: Covellite
Ore: Copper
Gangue: Quartz
Gangue: Apatite
Gangue: Goethite
Gangue: Pyrite
Gangue: Pyrrhotite

Comments

Comment (Geology): 5 N-NW Trending Gossan Zones (10-50 Ft. Wide) And Numerous N-Trending Zones (Up To 20 Ft. Wide). ; Geol.Desc: 5 North-Northwest Trending Gossan Zones(10-50 Ft. Wide)And Numerous North-Trending Zones(Up To 20 Ft. Wide)In Schistose Folded Quartz-Biotite Beds; Some Quartz Pods Present; Gossan Contains Goethite, Scorodite, Other Iron Arsenates, Copper Bloom, Some Cobaltite.

Comment (Development): 44 Unpatented Claims And Fractions And 3 Patented Claims ; Econ.Com: Sheared Wall Rock Creates Difficult And Expensive Mining Conditions

Comment (Workings): Pits, 4960 Ft. Diamond Drill Holes, Cat Road, Trenches

Comment (Commodity): Ore Occurs Disseminated And As Small Stringers Crossing The Shear Zones

Comment (Geology): Original ore control entry: Gossan Zones

Comment (Reserve-Resource): Because Of Incomplete Data No Specific Ore Reserves Have Been Calculated; However, If The Zones Are Continuous Reserves Up To 1300 Tons Of Ore Per Foot Of Depth, Having An Average Grade Of 0.453 Percent Cobalt And 1.176 Percent Copper, Are Indicated.

References

Reference (Deposit): Anderson, A.L., 1943, A Preliminary Report On The Cobalt Deposits In The Blackbird District, Idaho: Idaho Bureau Of Mines And Geology Pamph 61, P. 34

Reference (Reserve-Resource): Unpublished Cobalt Report

Reference (Deposit): Shockey, P.N., 1957, Reconnaissance Geology Of The Leesburg Quadrangle, Lemhi County, Idaho: Idaho Bureau Of Mines And Geology Pamphlet 113, 42 P.

Reference (Deposit): Umpleby, J.B., 1913, Geology And Ore Deposits Of Lemhi County, Idaho: USGS Bulletin 528, 182 P.

Reference (Deposit): Vhay, J.S., 1948, Cobalt-Copper Deposits In The Blackbird District, Lemhi County, Idaho: USGS Strategic Minerals Inv. Prelim. Rept. 3-219, 26 P.

Reference (Deposit): Johnson, Rick, Close, Terry, and McHugh, Ed, 1998, Mineral resource appraisal of the Salmon National Forest: U.S. Geological Survey Open-File Report 98-478, 277 p. (Stevenson Prospect Area p. 170-171)

Idaho Gold

"Where to Find Gold in Idaho" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in Idaho. Read more: Where to Find Gold in Idaho.