- Mineral Resources
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- Mica deposits of the Blue Ridge in North Carolina
Mica Mine in Avery county, North Carolina, this site also known as Big Andy
Joe Davis Rock (Big Andy) mine
Principal periods worked |
WWII, 1956 |
Workings |
Cut 250, adit 160, stope |
Description of muscovite |
Ruby to brownish green, cracked, bent, minor stain, small. |
Production |
Small sheet |
Shape |
Lenses |
Size |
0-20 T |
Strike |
N |
Dip |
E |
Relation to wallrock |
Concordant |
Wallrock |
Biotite gneiss |
Extent of weathering |
Unweathered |
Remarks |
Pl-P-Q-M pegmatite, medium to coarse grained; accessory biotite. |
Source of information |
USGS |
Abbreviations
Principal periods worked
WWI |
World War I |
WWII |
World War II |
int |
intermittent |
Production
Small |
< 500 lb |
Moderate |
500-10,000 lb |
Large |
> 10,000 lb |
Size of pegmatite
D |
depth |
L |
length |
T |
thickness |
avg |
average |
Internal structure
B |
biotite |
F |
feldspar |
M |
muscovite |
P |
perthite |
Pl |
plagioclase |
Q |
quartz |
Source information
CMC |
Colonial Mica Corporation |
DMEA |
Defense Minerals Exploration Administration |
OME |
Office of Minerals Exploration |
USGS |
U.S. Geological Survey |
OF |
USGS open-file reports and maps |