Ore Knob Mine

Past Producer in Ashe county in North Carolina, United States with commodities Copper, Gold, Silver, Zinc, Cobalt, Nickel, Iron
Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Ore body information
  13. Economic information about the deposit and operations
  14. Mineral rights holdings
  15. Land status
  16. Ownership information
  17. Production statistics
  18. Reserves and resources
  19. Workings at the site
  20. Links to other databases
  21. Bibliographic references
  22. General comments
  23. Reporter information

Geologic information

Identification information

Deposit ID 10150868
MRDS ID W101464
MAS/MILS ID 0370090006
Record type Site
Current site name Ore Knob Mine
Alternate or previous names Ore Knob Copper Mine

Geographic coordinates

Point of reference Geographic coordinates: Elevation UTM Precision Relative position Point location
Main Entrance -81.32762, 36.39948 (WGS84) 975 1000
(click for info)
-81.34148, 36.40424 (WGS84) Original MRDS entry

Site location context

Political divisions (FIPS codes)

Ashe(county)

North Carolina(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Laurel Springs(quadrangle 1:24,000 scale)

Boone(quadrangle 1:100,000 scale)

Winston-Salem(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper New(hydrologic unit)

Kanawha(hydrologic accounting unit)

Kanawha(hydrologic subregion)

Ohio(hydrologic region)

Geographic areas

Country State County
United States North Carolina Ashe

Comments on the location information

  • The Site encompasses approximately 165 acres, and is located in Ashe County, North Carolina, approximately 12 miles south of the Virginia state line, 45 miles southeast of Bristol, Tennessee, and eight miles east of the town of Jefferson, North Carolina.

Commodities

Commodity Importance
Copper Primary
Gold Secondary
Silver Secondary
Zinc Critical Secondary
Cobalt Critical Tertiary
Nickel Critical Tertiary
Iron Tertiary

Comments on the commodity information

  • The Ore Knob Mine was first worked for iron, but the wrought iron forged from the ore contained too much copper and sulphur, so production at the mine was shifted to copper.

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Actinolite Gangue
Biotite Gangue
Calcite Gangue
Epidote Gangue
Garnet Gangue
Hornblende Gangue
Quartz Gangue
Albite Gangue
Tourmaline Gangue
Alabandite Unknown
Bornite Unknown
Chalcocite Unknown
Chrysocolla Unknown
Magnetite Unknown
Malachite Unknown
Marcasite Unknown
Prochlorite Unknown

Alteration

  • (Local) Silicic
  • (Local) Calcic
  • (Local) Fe-Mg Enrichment

Mineral occurrence model information

Model code 91
USGS model code 24b
Deposit model name Massive sulfide, Besshi (Japanese deposits)
Mark3 model number 30

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Schist > Amphibole Schist
    Rock unit name Ashe Formation
    Stratigraphic age (youngest) Neoproterozoic

Nearby scientific data

Main Entrance (1) -81.32762, 36.39948
(2) -81.34148, 36.40424

Economic information

Geologic structures

Type of structure Local
Structure name SW plunging fold

Ore body information

  • Thickness 3M
    Length 457M
    Width 61M
    Area 25HA
    Depth to top 140M
    Field Value
    Type of Orebody #1 FISSURE VEIN
    Shape of Orebody #1 TABULAR
    Type of Orebody #2 SHEAR ZONE
    Shape of Orebody #2 LENTICULAR
    Primary mode of Origin HYDROTHERMAL
    Secondary mode of Origin OXIDATION
    Primary Ore Control LITHOLOGY
    Secondary Ore Control FAULTING
    Degree of Wallrock Alter. SLIGHT
    Type of Wallrock Alter. #1 PROPYLITIC
    Strike And Dip N63E:
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 12
    Min. Thick. Unconsol. Mat. 0
    Total Surface Area (HA) 25
    Date of Last Modification 780213
  • General form LENSES AND VEIN-LIKE
    Plunge 20 DEG SW
    Thickness 12M
    Length 1220M

Comments on the geologic information

  • Host rocks are mica-quartz-biotite-muscovite-oligoclase rocks. Schists with interbeds of amphibolite nearby. Vein-like and lenticular massive sulfide zones were tectonically concentrated along a SE plunging fold. Massive sulfide is up to 50-60% of the ore zone. Ore zone persists more than 1200 m down plunge and is 0.6 to 12 m thick. Gossan 12-18 m thick contains a supergene copper enriched blanket. Ore zone is thickened in fold hinges, and shows evidence of granulation and secondary coarsening during deformation. Deformation was largely confined to the ore zone which shows pinch and swell, rotation, and crenulations. Country rock shows effects of hydrothermal alteration up to 1.5 m from ore zone.

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Significant Yes
Discovery year 1855
Year of first production 1855
Year of last production 1962
Production years 1855-1856, 1873-1883, 1896, 1913, 1917, 1927, 1955-1962

Mineral rights holdings

Type of mineral rights Fee Ownership
Type of mineral rights Minerals Only
Type of mineral rights Private Lease

Land status

Ownership category Private

Ownership information

  • Type Owner-Operator
    Owner Appalachian Sulphides
    Year 1976
  • Type Owner
    Owner Virginia Rock And Minerals Co.
    Home office North Carolina
    Year 1976

Production statistics

  • Year 1883
    Period 1873-1883
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary Copper Copper 6wt-pct

Comments on the production information

  • Intermittent producer; 1855-1856; 1873-1883; 1896; 1913; 1917; 1927; 1955-1962.

Reserves and resources

  • Type In-situ
    Estimate year 1944
    Inferred 30000mt ore
    Total resources 30000mt ore
    Commodity Subtype Grade units Group Importance Year
    Cobalt Co 0.05 wt-pct Cobalt Trace 1944
    Gold Au 12.16 g/mt Gold Trace 1944
    Silver Ag 105.7 g/mt Silver Trace 1944
    Copper Cu 2 wt-pct Copper Trace 1944

Workings at the site

  • Type of workings Underground
    Overall depth 304M
    Overall length 914.4M
    Overall width 1.5M

Comments on the workings information

  • Two shafts connected eight levels. Most levels are 450 to 610 m long. Eleven shafts were sunk in the 1880's, the deepest being 121 m.

Reference information

Bibliographic references

  • Deposit

    Laurence, R. A., 1968, Ore Deposits Of The Southern Appalachin Ridge, J. D., Ed., Ore Deposits Of The United States, 1931, (Graton-Sales Volume) V. 1/ Am. Inst. Mining, Metall., and Petroleum Engineers

  • Deposit

    Vhay, J. S., 1952, Cobalt Resources, Chap. 6 Of Materials Survey - Cobalt: US Bureau of Mines

  • Deposit

    Vhay, J. S, Et. Al., 1973, Cobalt Chapter In Brobst, Donald A., Pratt, Walden P., Ed., United States Mineral Resources/ USGS Prof. Paper 820

  • Deposit

    Boyd, C. R., 1881, Copper-Ashe County, North Carolina/ Resources In Southwest Virginia

  • Deposit

    Hunt, T. Sterry, 1875, The Ore Knob Copper Mine and Some Related Deposits/ Am. Inst. Mining Enginers Trans, 1873-4.

  • Deposit

    Kerr, W. C. and Hanna, G. B., 1893, Ore Knob Copper Mine in Ore Knob North Carolina Chapter In Kerr, W. C., Ed., Geology Of North Carolina

  • Deposit

    Olcott, E. E., 1875, The Ore Knob Copper Mine and Reduction Ashe County, North Carolina/ Am. Inst. Mining Engineers Transcript

  • Deposit

    Staff, Bumines, 1943, Ore Knob Mine, Ashe County, NC, Bureau Of Mines War Minerals Report 61, 11 P.

  • Deposit

    Staff, Bumines, 1944, Ore Knob Mine, Ashe County, N. C. (Sup To WMR 61)/ US Bureau of Mines War Minerals Report 1

  • Deposit

    Ballard, T. J. and Clayton, A. B., 1948, Investigation of the Knob Copper Mine, Ashe County, North Carolina/ US Bureau Of Mines Report of Investigations 4341, 8 P.

  • Deposit

    Knob Copper Mine, Ashe County, North Carolina/ U. S. Bureau Of Mines Report of Investigations 4341, 8 P.

  • Deposit

    Tyler, Paul M., 1930, Cobalt: US Bureau Of Mines Information Circular 6331, 33 P.

  • Deposit

    Kinkel, Arthur R., Jr., 1962, The Ore Knob Massive Sulfide Copper Deposit, North Carolina- An Example Of Recrystallized Ore/ Economic Geology V. 57

  • Deposit

    Kinkel, A.R., 1967, The Ore Knob copper deposit, North Carolina, and other massive sulfide deposits of the Appalachians: US Geological Survey Professional Paper 558.

  • Deposit

    Ross, C. S., 1935, Origin of the Copper Deposits of the Duck Type in the Southern Appalachian Region/ US Geological Survey Prof. Paper 179, 165 P.

  • Deposit

    Gair, J.E., And Slack, J.F., 1979, Map Showing Lithostratigraphic And Structural Setting Of Stratabound (Massive) Sulfide Deposits In US Appalachians: US Geological Survey Open-File Report 79-1517.

  • Deposit

    Pierce, W. G., 1944, Cobalt-Bearing Manganese Deposits Of Alabama, Georgia, and Tennessee/ USGS Bulletin 940-J

  • Deposit

    Feiss, P.G., Maybin, A.H., III, Riggs, S.R., And Grosz, A.E., 1991, Mineral Resources of the Carolinas, in Horton, J.R., Jr., and Zullo, V.A., Eds., The Geology of the Carolinas: Knoxville, University of Tennessee Press

  • Deposit

    Stuckey, Jasper L, 1968, Mineral Resources Of North Carolina, North Carolina- Its Geology And Mineral Resources, North Carolina Department Of Conservation and Development

General comments

Subject category Comment text
General Site listed as a Superfund site with movement towards being placed on the NPL. Per an EPA information request (dated 02 Apr 2010), "The three principal areas include the 1950s Mine and Mill Area, the 19th Century Operations Area, and the Main Tailings Impoundment.

The 1950s Mine and Mill Area comprises 15 acres and is located northwest of the intersection of Ore Knob Road and Little Peak Creek Road, just north of Highway 88. This area contains derelict ore bins, concrete mill foundations, a transformer building, other ruins, a small sawmill currently in operation, two acres with about 10,000 cubic yards of tailings - now mostly covered with stumps - and a two-acre former pond where process water was stored. Little Peak Creek starts just upstream of the former pond, flows through the former pond, and discharges into Peak Creek 2.5 miles downstream.

The. 19th Century Operations Area and the Main Tailings Impoundment are located across Little Peak Creek Road, at the end of Ore Knob Mine Road. The 19th Century Operations Area includes a series of barren and nearly barren stretches of land (totaling about 5 acres) near the top of Ore Knob that contain waste rock dumps from at least 11 mine shafts, as well as locations where ore was roasted to drive off sulfur and smelted to recover copper. These waste materials occur in upland areas and are subject to erosion and down-slope transport.

The Main Tailings Impoundment is located about 0.3 miles northeast of the 19th Century Operations Area, covers approximately 20 acres, and is estimated to contain 720,000 cubic yards of tailings.' Tailings are the waste material left over after minerals have been extracted from ore mined at the Site. The tailings are strongly acid-generating and the average sample is characterized by high concentrations of numerous metals, including copper, zinc, arsenic, and mercury. Notably, the Tailings Impoundment is mostly barren of vegetation.

At the end of the Tailings Impoundment is a dam about 60 feet high and 700 feet wide. The dam has been subjected to severe erosion and water emanates from the dam in several places. The face of the damis deeply incised and erodes directly into a creek. The creek, the Ore Knob Branch, is piped underneath the Tailings Impoundment through a 24-inch pipe that exits the bottom of the dam face. The pipe discharges into a sediment pond that was full and did not have adequate space to contain the sediment and other precipitates from continuing down Ore Knob Branch. In addition, tailings slumped over the dam face and at least partially blocked the pipe, causing water to back up into the Tailings Impoundment and seep through the dam face. In addition, the upper end of the pipe is known to become blocked."
Deposit Year entered-1976. Entry is last known Owner/Operator, ceasing operations in 1962 (see reference 736, p. 284). Entry was a previous Owoer, 1943 (Ses ref. 723, / map name is Laurel Springs. The ore body was completely worked, the mine abandoned December 4, 1962 (see reference 736, p. 2) Data published in reference 721-722, p. 8. Commodity (Nickel) added July 19b7 by CAB.
Deposit Elongate plunging lens, 1.5-4.5 m thick, massive and disseminations. Limbs 0.5-1.5 m ore thickness; thickening to 12 m in fold hinge. Tectonic remobilization of stratabound exhalative sulfide layer. Layer follows axial plane of SW plunging fold. Ore plunge is 20 Degrees SW. Orebody maximum thickness 1.5 - 4.5 m. Sulfide in lenses and veins.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-1983 Whitlow, S. U.S. Geological Survey
Reporter 27-FEB-1984 Lyday, Travis Q. U.S. Bureau of Mines
Updater 01-JUN-1992 Klein, T.L. U.S. Geological Survey
Reporter 31-JUL-1995 Sachiko, Tanikawa U.S. Geological Survey
Editor 23-AUG-1995 Mosier, Dan U.S. Geological Survey
Editor 04-DEC-2003 Woodruff, Laurel G. U.S. Geological Survey Work done in Filemaker

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.