Mine detail: Cressmans Gulch Prospect

Previously called ''

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Location

Lat / long:

39.7861, -105.25614

Resource(B)

Primary:	Feldspar, Beryllium
Secondary:	Niobium (Columbium), Tantalum
Tertiary:	Mica
Ore:	Beryl, Microcline, Muscovite
Gangue:	Albite, Apatite, Biotite, Manganotantalite, Quartz, Tourmaline
Orebody form:	TABULAR

Production

Operation type:	Unknown
Production size:	Small
Development status:	Past Producer

Geology

Host rock:	Idaho Springs Formation-Hornblende Gneiss Unit
Host type:	Gneiss
Associated rock:	Granitic Pegmatite
Associated type:	Pegmatite
Structure:	Front Range Uplift, Denver Basin, Hurricane Hill Fault System
Tectonic:	Central Cordillera (Southern Rocky Mtns)

References

MRDS	D010191
DEP	10013733
Reference	{Deposit:: SHERIDAN, D.M., AND OTHERS, 1967, GEOLOGY AND URANIUM DEPOSITS OF THE RALSTON BUTTES DISTRICT, JEFFERSON COUNTY, COLORADO: USGS PROF. PAPER 520 (INCL. GEOLOGIC MAP OF RALSTON BUTTES QUAD)}{Deposit:: HANLEY, J.B., AND OTHERS, 1950, PEGMATITE INVESTIGATIONS IN COLORADO, WYOMING, AND UTAH, 1942-44: USGS PROF. PAPER 227, P. 86}{Deposit:: MEEVES, H.C., AND OTHERS, 1966, RECONNAISSANCE OF BERYLLIUM-BEARING PEGMATITE DEPOSITS IN SIX WESTERN STATES: USBM IC-8298, P. 27.}{Deposit:: USGS COMMODITY FILE, GR III, REEL 31, DOCK. 9937, 1945; GR III, REEL 32, DOCK. 10049, 1943; GR III, REEL 40, DOCK. 12742, 1944 (FROM ORIGINAL CRIB RECORD)}{Production:: ORIGINAL CRIB RECORD (SEE USGS REFERENCE)}
Reporter	Schwochow, Stephen D.