Subject: History of Mining in the Mitchell County Area
By: Barbara Manojlovich
Content information provided by Geologist Alex Glover
efore recorded history, as long as 2000 years ago, the native Americans of Mitchell County mined the area for mica which they used in grave decoration and for trade. They mined what is now the Clarissa, Ray, Hawk and Sinkhole mines and traded their mica well into the Ohio Valley. An ancient Spanish helmet was found in Mitchell County near the Sinkhole Mine which led to the story that Hernando Desoto came here in search of silver and gold around 1540; or perhaps some native Americans killed one of his men down near the Natchez Trace trade route in Mississippi and carried the helmet here to trade for mica. In the 1700's, Cherokees mined a feldspar, quartz and kaolin mixture, which was moved to the coast by oxen and shipped to England for the beautiful china and porcelain that flourished in Europe at that time. Since 1868 sheet mica has been mined commercially; first, at the Hawk Mine north of Spruce Pine and then from more and more open pits. The large mica books were split and used for windows in wood stoves and for electric motors. From 1893 scrap mica has been ground for various things such as an anti-shrinking ingredient in glue. Green mica is found along Crabtree Creek, gradually becoming brown around Kona and Penland, and eventually reddish brown on the north side of Mitchell County near Hawk and English Knob. William Dibbell founded the Carolina Minerals Co. of Penland which shipped its first production of feldspar from the Deer Park Mine in 1911 to ceramic plants in Ohio. In 1914 grinding plants in Erwin, Tennessee were set up by the same sources that established the Clinchfield Railroad. And by 1923 there were plants in Beaver Creek and Micaville, NC for grinding both feldspar and mica. The Deer Park Mine on the North Toe River, the Hawk Mine, Sinkhole and several others had (like coal mines) deep shafts as much as 3-400 ft down, where mining of feldspar was done on4 or 5 different levels. Most of these mines are not worked today, but their owners do not want tourists poking around and falling down the deep shafts. Later feldspar mining was done by dynamiting huge open caves such as remain at the Hoot Owl Mine and the McKinney Mine. Today, companies like U.S. Feldspar are eating up an entire mountain known as Chalk Mountain, which was sold to them for $1.00 per ton and which is visible from U.S. 19 E and by terracing or strip mining as at the Lawson Mine which can be seen from NC 226 as you approach Spruce Pine, but these mines are secured from rockhounds for safety reasons. There are many gemstones in Mitchell County including emerald, aquamarine, golden beryl, garnet, smoky quartz, tourmaline, spodumene, moonstone, kyanite, sunstone, amazonite, and unakite. At The Emerald Mine our family and friends throughout the county, who have been involved in mining for generations, have given us permission to haul material that is likely to contain many of these gemstones to our safe location. Here everyone can enjoy 3 different types of mining: washing material in our sluice trough, real digging or panning for gold.
The geologic history of the Spruce Pine Mining District is as fascinating as its mining history. About 380 million years ago, the African Continent was being forced toward the Ancestral Eastern North American Continent by plate tectonic force. The subduction, or forcing down of the Oceanic Crust underneath the North American Continent produced tremendous friction-generated heat from the two colliding continents. This friction-generated heat in excess of 2,000 degrees Fahrenheit melted the surrounding rock 9 to 15 miles below the surface. This igneous molten rock was generated under intense pressure that forced the molten rock into cracks and fissures of preexisting rock. This molten rock under pressure is similar to hot hydraulic fluid being forced into a chamber. Due to the pressure exerted on the molten fluid, it hydraulically pushed its way through the cracks of the host rock. this opened the rock up, along with melting contact areas of the host rock and sucking up rich mineral forming fluids. As these cooled, they crystallized and became a mineral-rich buried treasure. It then took an estimated 100 million years for this deeply buried (and insulated) mass to cool and crystallize. The slowly cooling mineral crystals grew within the Spruce Pine District to some of the largest feldspar and mica crystals in the world. After molten emplacement and cooling, it took millions of more years of Appalachian Mountain building and subsequent erosion to expose the deposits we see today.
Modern day mining methods, research, plant production, and product development have enabled the use of these high purity natural resources from the earth to enhance our quality of life.
Feldspar is a major ingredient in the manufacture of many types of glass, from automobile windshields and computer screens to baby food bottles and electric light bulbs. Feldspar comprises about 65% of the rock from the Spruce Pine pegmatite and is a major source of aluminum, sodium and potassium for glass manufacturing. Feldspar provides aluminum, which improves glass workability during forming, retards glass blooming, improves glass strength and imparts resistance to thermal shock. About 110 pounds of feldspar is used to make a ton of container glass (bottles and jars) and about 100 pounds is used to make a ton of flat glass (auto windshields and window glass). Feldspar is also a major ingredient in the manufacture of ceramic products. it acts as a flux to fuse (melt) other ingredients at lower temperatures; it cements the crystalline phases of other ingredients together; and it imparts strength, durability, and toughness to ceramic bodies. Feldspar's special qualities and glazing properties allow ceramic product manufacture of pottery, plumbing fixtures (sinks and toilets), electrical porcelain, ceramic tile, dinnerware, structural ceramics, art pottery, planters and much more. The use of feldspar in the manufacture of ceramics has come a long way since its development during the Tang Dynasty of China around A.D. 621 to 945.
Mica, another ingredient from the rock of the Spruce Pine Mining District comprises about 10% of the rock mass. Once highly valued for wood- and coal-burning stove windows (often called isinglass) and for radio tube insulators during both world wars, it is now used as an industrial products special additive. Muscovite, which is silver to white mica variety, is mostly ground to a fine particle size. It is valued for its flat particle shape. It is used mostly as a major ingredient of drywall joint compound or sheet rock joint cement. Muscovite's flat particle shape and light color allow it to serve as an anti-shrinking agent for the cement after it is applied to sheet rock joints. It applies as smooth, damp putty, but because of muscovite mica's flat particle shape, it interlocks the mud as it dries, therefore reinforcing the mud as it dries, without shrinkage. It also acts as a fire retardant within the sheet rock joint. Mica is also produced from the Spruce Pine Mining District for use as special electrical insulators, automobile metallic flake paint, women's make-up, and as a reinforcing additive in special plastics and paints. It is used in oil well drilling fluids to seal and lubricate the bore hole during drilling.
Another major ingredient of the Spruce Pine rock is quartz. Through the years, quartz was always discarded as waste. Now it is recovered through froth flotation and is used as industrial sand in concrete and concrete mortar. It is also a highly-valued white golf course trap sand and is sold across the country to the finest golf courses, including the Augusta National, the host for the Masters. Comprising about 25% of the rock, the quartz has now become one of the most strategic minerals of the entire world. Because of its extreme purity, it is used in several critical process steps during the manufacture of computer semiconductors (chips). At present, no other quartz in the world can match the processed quartz purity from the Spruce Pine District. As a matter of fact, Every computer chip in the world uses Spruce Pine quartz in its manufacturing process. Also of high value to the lighting industry, the Spruce Pine quartz meets stringent purity requirements to serve as extreme high temperature light tubing required for light bulbs installed in automobiles, streetlights, and film projectors.