Twiggs mine

Mica Mine in Mitchell county, North Carolina

Twiggs mine

Principal periods worked WWII, 1956-58
Workings 4 Adits, shaft 100, stopes, drift 93.
Description of muscovite Greenish brown, hard, bent, cracked, stained.
Production Moderate sheet
Shape Tabular, pinch and swell.
Size 0.1-3 T, 200 L, 150 D.
Strike NE
Dip SE
Plunge NE
Relation to wallrock Concordant
Wallrock Interlayered biotite and hornblende gneiss
Extent of weathering Unweathered
Remarks Pl-Q-M pegmatite, fine to medium grained; accessory garnet, pyrite, chlorite, epidote, biotite.
Source of information USGS, 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