Red Top

Mine, Inactive

Commodities and mineralogy

Main commodities Ag; Au
Other commodities Cu; Pb; W; Zn
Ore minerals arsenopyrite; galena; gold; jamesonite; limonite; marcasite; melanterite; polybasite; pyrargyrite; pyrite; scheelite; scorodite; sphalerite; sulfur; tetrahedrite
Gangue minerals quartz; siderite

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5399
Longitude -150.9745
Nearby scientific data Find additional scientific data near this location
Location and accuracy
The Red Top mine (Cobb, 1980 [OFR 80-363]) is on the
westernmost flank of Quigley Ridge above Friday Creek. The main workings are at elevations of about 1850 to 2200 feet. The mine is about 0.4 mile east-northeast of the point where Friday Creek crosses the Kantishna road. The location is accurate within 300 feet. (The mine named Red Top at the head of Lucky Gulch on the Mt. McKinley C-2 quadrangle map actually is the Banjo mine, MM097).
The site corresponds to location 7 of Cobb (1972 [MF 366]), 6 of MacKevett and Holloway (1977), E of Hawley and Associates (1978), 18 of Bundtzen, Smith, and Tosdal (1976), 19 of Bundtzen (1981), and 28 of Thornsberry, McKee, and Salisbury (1984).

Geologic setting

Geologic description

The country rocks near the Red Top mine are metafelsite, chloritic and graphitic phyllite, and impure marble of the Spruce Creek sequence (Bundtzen, 1981). A fault north of Friday Creek strikes east-northeast and separates the Spruce Creek rocks from Birch Creek Schist (Thornsberry, McKee, and Salisbury, 1984, fig. K-2).
Veins and ore zones in the Red Top mine are controlled by complex, intersecting faults. The veins tend to have sharp hanging walls and gradational footwalls. At the portal of the Red Top mine, a 1- to 3-foot-thick vein that strikes E-W to ENE and dips about 55 S, cuts faulted and altered chloritic phyllite. This vein was extremely rich: 3-foot-long samples collected across the vein on 5- to 10-foot centers from 10 to 45 feet along the adit (measured from the portal) assayed 0.58-1.96 ounces of gold per ton and 238 to 1717 ounces of silver per ton (Davis, 1923; Wells, 1933). This part of the vein contained polybasite, pyrargyrite, and tetrahedrite or freibergite. Associated sulfide minerals were arsenopyrite, pyrite, galena and sphalerite. About 180 tons of ore mined in about 1922 from this part of the mine averaged 1.1 ounces of gold per ton and 237 ounces of silver per ton (Bundtzen, 1981).
Between 150 feet and 280 feet along the main adit, a 10- to 20-foot thick vein strikes about N 60 E and dips steeply S. Most of this vein is consistently mineralized, but of low- to medium-grade (Davis, 1923, p. 122; Wells, 1933, pl. 30). Part of the vein consists only of limonitic quartz, and part consists of quartz, siderite, galena, arsenopyrite, tetrahedrite, and probably lead sulfosalts.
The relations between the high-grade and low- to moderate-grade veins are uncertain. Bundtzen, Smith, and Tosdal (1976) proposed multiple mineralization along complex, interlaced faults. Most of the high-grade ore contained abundant arsenopyrite; the lower-grade ore mainly was rich in galena (Wells, 1933, p. 362-363).
The Red Top vein is truncated by an E-W fault at about 290 feet in the adit. The vein was not recovered, although vein outcrops on the surface beyond the fault suggest only minor fault displacement, and that the vein continues uphill to the northeast.
Mine water at Red Top is strongly acidic and corrosive. Melanterite and native sulfur formed on the drift walls in ore-bearing sections of the deposit, and marcasite formed from acidic attack on the primary sulfides.
Geologic map unit (-150.976786998987, 63.5393929894939)
Mineral deposit model Polymetallic veins (Cox and Singer, 1986; model 22c).
Mineral deposit model number 22c
Age of mineralization The deposit is assumed to be Eocene (see record MM091).
Alteration of deposit Silicification. Oxidation of iron minerals. Formation of melanterite, native sulfur, and marcasite due to acidic mine water.

Production and reserves

Workings or exploration
The Red Top deposit was discovered and the mine first developed by J. B. Quigley. Ore was mined from the high-grade portal shoot in 1922, but not shipped until later (Davis, 1923). Production continued until about 1925 (Moffit, 1933). Despite extremely high grade ore, the mine may not have been profitable because of high shipping costs (Brooks, 1925). There was renewed interest in the property before World War II, but it is not known if any more ore was shipped. Joesting (1942), investigating strategic minerals throughout Alaska during World War II, found that table concentrates from Red Top ore were rich in scheelite. There was further interest in the Red Top deposit beginning in about 1970, when some of the workings were reopened and a mill built on the property. This venture apparently was not successful. There was no substantial development after the early period of mining, which ended by 1925.
In 1983, the U.S. Bureau of Mined drilled three diamond core holes on the property. Hole K-19, drilled about 150 northeast of the mine portal, intersected a strongly mineralized section between 148 feet and 176.4 feet. This 28.4-foot section assayed 0.137 ounce of gold per ton and 3.37 ounces of silver per ton. The best 10-foot section of this zone assayed a little more than 0.2 ounce of gold per ton and 8.09 ounces of silver per ton. Base metal contents were negligible, although arsenic assays reached 2.89 percent in the 28.4 foot section. The section apparently correlates with a low- to moderate-grade vein exposed in the mine. The two other holes (K-20 and K-21) did not intersect significant mineralization (Thornsberry, McKee, and Salisbury, 1984, v. 2, occurrence 28).
Indication of production Yes; small
Production notes Production during the main period of mining in the early 1920s was about 187 ounces of gold, 43,600 ounces of silver, and 93,200 pounds of lead from about 183 tons of ore (Bundtzen, Smith, and Tosdal, 1976, p. 25).

Additional comments

The Red Top mine is in Denali National Park and Preserve.

References

MRDS Number A011248; D002717

References

Bundtzen, T.K., 1981, Geology and mineral deposits of the Kantishna Hills, Mt. McKinley quadrangle, Alaska: M. S. Thesis, University of Alaska, College, Alaska, 238 p.
Reporters C.C. Hawley
Last report date 4/26/2001