Star Girl Mine

Past Producer in Park county in Colorado, United States with commodities Mica, Feldspar, Beryllium

Sections on this page

Identification information
Geographic coordinates
Site location context
Geographic areas
Public Land Survey System information
Commodities
Materials information
Mineral occurrence model information
Host and associated rocks
Nearby scientific data
Geologic structures
Ore body information
Economic information about the deposit and operations
Mining district
Land status
Ownership information
Workings at the site
Links to other databases
Bibliographic references
General comments
Reporter information

Geologic information

Identification information

Deposit ID	10013526
MRDS ID	D009876
MAS/MILS ID	80930245
Record type	Site
Current site name	Star Girl Mine
Alternate or previous names	Colorado Feldspar Company Mine

Geographic coordinates

Point of reference	Pit
Geographic coordinates:	-105.481, 38.69991 (WGS84)
Elevation	2819
Location accuracy	10(meters)
Relative position	4.0 MILES S 56 E OF GUFFEY. Mine sumbol laabeled "Mine" on topo. Corresponds to Fig. 7 of PP-227.

Site location context

Political divisions (FIPS codes)

Park(county)

Colorado(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Cover Mountain(quadrangle 1:24,000 scale)

Pikes Peak(quadrangle 1:100,000 scale)

Pueblo(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Arkansas Headwaters(hydrologic unit)

Upper Arkansas(hydrologic accounting unit)

Upper Arkansas(hydrologic subregion)

Arkansas-White-Red(hydrologic region)

Federal lands

Bureau of Land Management(Bureau of Land Management CO)

Bureau of Land Management CO BLM(Type of land area)

BLM(Federal land areas administered by BLM)

Geographic areas

Country	State	County
United States	Colorado	Park

Public Land Survey System information

Meridian	Township	Range	Section	Fraction	State
6th Principal	015S	072W	32	S2 OF NW OF SW	Colorado

Comments on the location information

EAST OF MACK GULCH

Commodities

Commodity	Importance
Mica	Primary
Feldspar	Primary
Beryllium Critical	Tertiary

Materials information

Materials	Type of material
Beryl	Ore
Microcline	Ore
Muscovite	Ore
Apatite	Gangue
Biotite	Gangue
Garnet	Gangue

Mineral occurrence model information

Model code	32
USGS model code	13
Deposit model name	Pegmatites

Host and associated rocks

Host or associated

Associated

Rock type

Plutonic Rock > Mafic Intrusive Rock > Diorite

Rock unit name

Quartz Diorite Of Boulder Creek Age

Rock description

Quartz Diorite Of Boulder Creek Age

Stratigraphic age (youngest)	Neoproterozoic
Stratigraphic age (youngest)	Neoproterozoic
Stratigraphic age (youngest)	Neoproterozoic

Host or associated Host

Rock type Metamorphic Rock > Gneiss

Host or associated	Host
Rock type	Metamorphic Rock > Gneiss

Nearby scientific data

Pit (1)	-105.481, 38.69991	ListMap

Economic information

Geologic structures

Type of structure	Regional
Structure description	Southern Front Range, Thirtynine Mile Volcanic Field

Ore body information

Strike N

Dip STEEP TO EAST

Thickness 9.14M

Length 18.29M

Width 15.24M

Depth to top 0M

Depth to bottom 9.14M
General form Type of Orebody #1: PEGMATITE Primary mode of Origin: MAGMATIC DIFFERENTIATION

Strike	N
Dip	STEEP TO EAST
Thickness	9.14M
Length	18.29M
Width	15.24M
Depth to top	0M
Depth to bottom	9.14M

General form	Type of Orebody #1: PEGMATITE Primary mode of Origin: MAGMATIC DIFFERENTIATION

Economic information about the deposit and operations

Operation type	Surface
Development status	Past Producer
Commodity type	Both
Deposit size	Small
Significant	No
Discovery year	1950
Year of first production	1950

Mining district

District name	Micanite District

Land status

Ownership category	Private

Ownership information

Type Owner

Owner Colorado Feldspar Co.

Home office Canon City, Co.

First year 1979
Type Unknown

Owner United States Mica Co.

Year 1950

Type	Owner
Owner	Colorado Feldspar Co.
Home office	Canon City, Co.
First year	1979

Type	Unknown
Owner	United States Mica Co.
Year	1950

Comments on the reserve resource information

ESTIMATED TO BE ONLY A FEW HUNDRED TONS EACH OF SCRAP MICA AND MICROCLINE AS RESERVES (1950)
MICROCLINE - PROBABLY NOT MORE THAN 300 TONS.

Workings at the site

Type of workings Unknown

Area 0.026HA

Length 30.48M

Overall depth 9.14M

Overall length 60M

Overall width 50M

Type of workings	Unknown
Area	0.026HA
Length	30.48M
Overall depth	9.14M
Overall length	60M
Overall width	50M

Comments on the workings information

INCLINED SHAFT AT LEAST 30-FT DEEP, 2 LEVELS OF DRIFTS, (ONE AT 15-FT, OTHER AT 30 FT); OPEN CUT 60X50X30 FT DEEP

Reference information

Links to other databases

Agency	Database name	Acronym	Record ID	Notes
USGS	Mineral Resources Data System	MRDS	D009876
U.S. Bureau of Mines	Minerals Availability System	MAS	80930245
USGS	Mineral Resources Data System	MRDS	D004963	= newMRDS 10215603 and 10010885, merged and deleted.

Bibliographic references

Deposit

HANLEY, J. B., HEINRICH, E. W., PAGE, L. R., 1950, PEGMATITE INVESTIGATIONS IN COLORADO, WYOMING, AND UTAH, 1942-1944: USGS PROFESSIONAL PAPER 227, P. 42-55.
Deposit

WOBUS, R. A., EPIS, R. C. AND SCOTT, G. R., 1979, GEOLOGIC MAP OF THE COVER MOUNTAIN QUADRANGLE, FREMONT, PARK, AND TELLER COUNTIES, COLORADO: USGS MAP I-1179, 1:62,500.
Deposit

MINOBRAS, 1974, colorado and Utah Industrial Minerals.

General comments

Subject category	Comment text
Deposit	Text that follows taken in its entirety from PP-227, p. 50-51: The Star Girl mine (#81, plate in PP-227), which is about 2,400 feet north of the Climax mine (see fig. 7, PP-227), has been worked twice, once during the early mica mining and later during recent feldspar operations. The underground workings made in search for mica have been almost completely destroyed by the feldspar mining. They include an inclined shaft at least 30 feet deep and a network of drifts at two levels, one 15 feet and the other 30 feet in depth. An open-cut about 60 feet in length, 50 feet in width, and as much as 30 feet in depth was excavated in mining the feldspar. The trend of the pegmatite is north, and the dip is steep to the east. The hanging-wall contact with the granitic gneiss wall rock is obscure, and numerous pegmatite stringers extend into the wall rock. The internal structure of the pegmatite is moderately well exposed, and three major zones can be recognized. The wall zone of quartz-microcline-plagioclase-muscovite pegmatite is separated from the core of quartzmicroline pegmatite by a thin, discontinuous intermediate zone of quartz-plagioclase-muscovite pegmatite. A border zone less than half an inch thick, having the same composition as the wall zone but a much finer texture, is exposed at one place in the old workings. The quartz-microcline-plagioclase-muscovite pegmatite contains as accessory minerals dark-brown garnet in 2-inch crystals, olive-green apatite in crystals as much as 3 inches in width, and small plates of biotite. This rock has an average grain size of 1.5 inches and is granitic in texture. The quartz-plagioclase-muscovite pegmatite contains a pale-pink plagioclase and light-green muscovite that occurs in radiating wedges and irregular clusters as much as 4 feet in size. The muscovite is ruled and wedged and has pronounced "A" structure; none was observed that could be used as sheet mica. However, as it is hard and free of mineral inclusions, it should yield good scrap mica. The exposures in the open-cut are visually estimated to contain between 5 and 10 percent muscovite. The quartz-microcline pegmatite contains massive white quartz and subhedral masses of light-red microcline as much as 4 feet in length. Quartz is estimated to be about twice as abundant as microcline in this zone. The scrap mica reserves are uncertain because the tonnage of mica-bearing pegmatite removed during the United States Mica Go's, operations cannot be determined, but they are estimated at a few hundred tons. Most of the microcline in the core has been mined, and the remaining reserves are estimated to be only a few hundred tons.
Deposit	3 ZONES: WALL ZONE IS QTZ-MICROCLINE-PLAGIOCLASE-MUSCOVITE PEGMATITE, INTERMEDIATE ZONE IS THIN, DISCONTINUOUS QUARTZ-PLAGIOCLASE-MUSCOVITE PEGMATITE, CORE IS QUARTZ-MICROCLINE PEGMATITE; BORDER ZONE IN SOME PLACES

Subject category

Comment text

Deposit

Text that follows taken in its entirety from PP-227, p. 50-51: The Star Girl mine (#81, plate in PP-227), which is about 2,400 feet north of the Climax mine (see fig. 7, PP-227), has been worked twice, once during the early mica mining and later during recent feldspar operations. The underground workings made in search for mica have been almost completely destroyed by the feldspar mining. They include an inclined shaft at least 30 feet deep and a network of drifts at two levels, one 15 feet and the other 30 feet in depth. An open-cut about 60 feet in length, 50 feet in width, and as much as 30 feet in depth was excavated in mining the feldspar. The trend of the pegmatite is north, and the dip is steep to the east. The hanging-wall contact with the granitic gneiss wall rock is obscure, and numerous pegmatite stringers extend into the wall rock. The internal structure of the pegmatite is moderately well exposed, and three major zones can be recognized. The wall zone of quartz-microcline-plagioclase-muscovite pegmatite is separated from the core of quartzmicroline pegmatite by a thin, discontinuous intermediate zone of quartz-plagioclase-muscovite pegmatite. A border zone less than half an inch thick, having the same composition as the wall zone but a much finer texture, is exposed at one place in the old workings. The quartz-microcline-plagioclase-muscovite pegmatite contains as accessory minerals dark-brown garnet in 2-inch crystals, olive-green apatite in crystals as much as 3 inches in width, and small plates of biotite. This rock has an average grain size of 1.5 inches and is granitic in texture. The quartz-plagioclase-muscovite pegmatite contains a pale-pink plagioclase and light-green muscovite that occurs in radiating wedges and irregular clusters as much as 4 feet in size. The muscovite is ruled and wedged and has pronounced "A" structure; none was observed that could be used as sheet mica. However, as it is hard and free of mineral inclusions, it should yield good scrap mica. The exposures in the open-cut are visually estimated to contain between 5 and 10 percent muscovite. The quartz-microcline pegmatite contains massive white quartz and subhedral masses of light-red microcline as much as 4 feet in length. Quartz is estimated to be about twice as abundant as microcline in this zone. The scrap mica reserves are uncertain because the tonnage of mica-bearing pegmatite removed during the United States Mica Go's, operations cannot be determined, but they are estimated at a few hundred tons. Most of the microcline in the core has been mined, and the remaining reserves are estimated to be only a few hundred tons.

Deposit

3 ZONES: WALL ZONE IS QTZ-MICROCLINE-PLAGIOCLASE-MUSCOVITE PEGMATITE, INTERMEDIATE ZONE IS THIN, DISCONTINUOUS QUARTZ-PLAGIOCLASE-MUSCOVITE PEGMATITE, CORE IS QUARTZ-MICROCLINE PEGMATITE; BORDER ZONE IN SOME PLACES

Reporter information

Type	Date	Name	Affiliation	Comment
Reporter	1980-06-01	Foord, Suzann C.	U.S. Geological Survey	MRDS D004943
Reporter	1982-12-01	Collins, Donna B.	Colorado Geological Survey	Collins also updated D004943
Reporter	1992-05-29	Martin	U.S. Bureau of Mines	MAS 0080930245
Editor	2012-10-02	Wilson, Anna B	U.S. Geological Survey	merged and deleted duplicate references. Verified and corrected info based on cited references.

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

External references

Wikidata: Q49451043 (Star Girl Mine)

Maps centered on this site

Authoritative Colorado resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.