Bluff mine

Mica Mine in Avery county, North Carolina

Bluff mine

Principal periods worked Int. 1890-1940, 1943-44.
Workings 9 cuts, 5 adits, irregular rooms.
Description of muscovite Greenish brown, moderate stain, bending, ruling.
Production Moderate sheet
Shape Lenses
Size 3 T
Strike NE
Dip SE
Relation to wallrock Concordant
Wallrock Interlayered hornblende and biotite gneiss
Extent of weathering Weathered (10+ ft).
Remarks Pl-Q-P-M pegmatite, coarse grained; accessory apatite, garnet, sericite. Larger lenses of fine grained Pl-P-Q pegmatite also present.
Source of information USGS, OF

Geographic context

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