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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 Old Hennessey
Tom Carpenter (Old Hennessey) mine
Principal periods worked |
Pre-WWII |
Workings |
3, adits, 2 are 100 ft long and connected underground. |
Description of muscovite |
Dark brown, moderate stain, bending, ruling. |
Production |
Moderate sheet |
Shape |
Irregular trough. |
Size |
20 T, >100 L |
Strike |
NW |
Dip |
NE., SW |
Relation to wallrock |
Concordant |
Wallrock |
Mica gneiss |
Extent of weathering |
Unweathered |
Remarks |
Pl-Q-P-M pegmatite; accessory, biotite-vermiculite (in strips 1-4 ft long, concentrated near footwall), allanite. |
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 |