Benfield mine

Mica Mine in Avery county, North Carolina, this site also known as Tom Benfield

Benfield (Tom Benfield) mine

Principal periods worked 1895, 1910, 1943
Workings 6, adits, one at least 120 ft long. All caved.
Description of muscovite Ruby, hard, minor stain. Some books have brown centers, green edges.
Production Moderate sheet
Shape Lenses
Size 1-3 T
Strike NW
Dip NE
Relation to wallrock Concordant
Wallrock Interlayered hornblende and biotite gneiss
Extent of weathering Saprolite (15+ ft).
Remarks Pl-P-Q-M pegmatite, medium to coarse grained, accessory garnet.
Source of information USGS, CMC

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