Henson Slope mine

Mica Mine in Avery county, North Carolina

Henson Slope mine

Principal periods worked Pre-WWII
Workings Adit
Description of muscovite Greenish brown, moderately stained, "A" structure, biotite intergrowths, locky, small.
Shape Tabular
Size Thick
Strike NE
Dip NW
Relation to wallrock Concordant(?)
Wallrock Mica gneiss
Remarks Pl-P-Q-M wall zone, medium grained;a P-PL-Q intermediate zone; accessory muscovite; Q core. Some graphite texture.
Source of information USGS

Geographic context


Principal periods worked
WWI World War I
WWII World War II
int intermittent
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