Download Guidebook as .pdf (2.2 Mb) - Carolina Geological Society

additional quality, mica’s dielectric properties, which made it a peerless electrical
insulator. “Until a few years ago, almost the only commercial use of mica was in the
doors or windows of stoves and furnaces. To a less extent it was used in lanterns and the
portholes of naval vessels, where vibrations would demolish the less elastic glass. . . .
Since the introduction of the present system of generating electricity, there has risen a
considerable demand for it in the construction of dynamos and electric motors” (Merrill
1901:290).
THE HISTORICAL PERIOD OF MICA MINING
The workings at Bandana eventually grew to include over 30 shafts and 2,000–3,000 ft of
drifts and stopes. The deepest shafts were connected below by a 900-ft tunnel which
drained water that otherwise would have filled the underground workings. The tunnel
extended under the paved road that is now N.C. Highway 80 (Figures 5 and 6). In the
latter decades of the nineteenth century, the Sink Hole was known as a source of the
highest grade of flat stove mica. In the twentieth century, when electrical and electronic
applications overshadowed older uses, the Sink Hole became renowned as the source for
a variety of reddish brown muscovite mica, known as “ruby” in the trade, that was
regarded as possessing the highest dielectric properties and therefore preferred by
industry.
Activity at the mine fluctuated over a 90-year period. When sheet mica was in
demand, the selling price rose and fell depending on the amount imported from abroad
(chiefly India) and the needs of the defense industry. After a 20-year interruption
following the First World War, new shafts were sunk in 1941 a short distance southwest
of Clingman’s original shaft (see Olson 1944:Plate 5), as America prepared once more to
go to war. In 1942, the U.S. Government established the Colonial Mica Corporation,
headquartered in Asheville with an office in Spruce Pine, in order to encourage local
miners by offering to buy all the mica they could produce and to help finance the
purchase of mining equipment.
With peace, work came to a halt in 1945, only to be revived again by the Korean
War. The buying program was reestablished in 1952, when the government began
stockpiling mica to ensure against interruptions in overseas supplies. During the 10-year
period from 1952 to 1962, the mine produced over 200,000 pounds of sheet mica
(Lesure, 1968:68). When the federal buying program ended in 1962, so did activity at the
Sinkhole Mine.
ANCIENT MINERS
When Clingman and Kerr visited Bandana, signs of prehistoric activity there consisted of
deep pits and trenches with stone tools left lying in the bottom. The actual identity of
Bandana’s prehistoric miners is a matter of conjecture; however, questions about why the
mica was mined, how it was used, and where it was used was solved by the excavation of
burial mounds hundreds of miles away in the Ohio River Valley of Ohio, Kentucky, and
West Virginia.
In 1913, some four decades after Clingman searched for silver there, W. H.
Holmes visited Bandana to investigate reports of aboriginal tools found in mica mines of
the Spruce Pine district. He arrived at a time when modern work had not quite obliterated
the ancient diggings. Holmes appears to have been the second archaeologist to investigate
287