Keystone Lode

The Keystone Lode is a beryllium, lithium, and mica mine located in Custer county, South Dakota at an elevation of 5,600 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: Keystone Lode

Commodity

Primary: Beryllium
Primary: Lithium
Primary: Mica

Location

State: South Dakota
County: Custer
District: Custer 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: Black Hills

Holdings

Not available

Workings

Not available

Ownership

Owner Name: Maywood Chemical Co. Of Maywood, Nj

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Interior Plains
Physiographic Province: Great Plains Province
Physiographic Section: Black Hills

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Not available

Alterations

Not available

Rocks

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

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

Analytical Data

Analytical Data: 5% OF THE PEGMATITE IS MICA. THE BERYL CRYSTALS ARE PALE YELLOW AND ABOUT 4 INCHES IN DIAMETER

Materials

Ore: Beryl
Ore: Muscovite
Ore: Amblygonite
Gangue: Hornblende
Gangue: Albite
Gangue: Quartz
Gangue: Pyrrhotite
Gangue: Microcline

Comments

Comment (Deposit): EXACT SHAPE AND DIP OF PEGMATITE HAVE NOT BEEN DETERMINED

Comment (Workings): SEVERAL SHALLOW CUTS

References

Reference (Deposit): USGS PP 247, P. 141

Reference (Deposit): USBM INFO CIRC 7707, P. 120

Reference (Deposit): SDSMT BULL 18

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