Doublehead mine (SE)

Mica Mine in Avery county, North Carolina, this site also known as Brown workings, (See also Learning Locust mine)

Doublehead mine (SE) Brown workings. (See also Leaning Locust mine.)

Principal periods worked 1870, 1890's, 1920's, WWII, 1950's
Workings 10 cuts, 9 adits, drifts, stopes, inclines, in area 200 by 500.
Description of muscovite Dark brown to brownish green,, cracked, minor "A" structure, ruling, bending, mineral inclusions, biotite intergrowths.
Production Large sheet
Shape Irregular tabular, lenses.
Size Main body 2-20 T 500 L; lenses 1-10 T.
Strike NW
Dip SW
Plunge SE
Relation to wallrock Discordant
Wallrock Interlayed hornblende and biotite gneiss
Extent of weathering Partly weathered
Remarks Pl-Q-P-M pegmatite, medium to coarse grained; accessory biotite, garnet, apatite, tourmaline, pyrite. Numerous lenses of similar pegmatite have been prospected nearby.
Source of information USGS, Sterrett (1923, p. 179), DMEA.

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