Friday Creek

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Pb; Sb; W
Ore minerals galena; gold; pyrite; scheelite; stibnite
Gangue minerals garnet; magnetite

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5431
Longitude -150.9665
Nearby scientific data Find additional scientific data near this location
Location and accuracy Friday Creek is only about two miles long, including its steep headward forks (Cobb, 1980 [OFR 80-363]). It rises against the west flank of Wickersham Dome, drains the north flank of Quigley Ridge, and flows westerly into Moose Creek (MM132). The location is at the approximate midpoint of the extensively mined section of the creek. It is at an elevation of about 1900 feet, nearly coincident with the location of Friday Creek by Hawley and Associates (1978), which they base on a summary of Alaska mining claims (Kardex) by Heiner and Porter (1972). Friday Creek is location 45 of Cobb (1972 [MF 366]). The location of various resource blocks on the creek is shown by Thornsberry, McKee, and Salisbury (1984, fig. K-3), and by Levell (1984 [v. 2]).

Geologic setting

Geologic description

Friday Creek drains an area underlain mainly by metafelsite and chloritic phyllite of the the lower Paleozoic Spruce Creek sequence (Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, fig. K-2). Bedrock lithologies encountered in placer mining include quartzitic schist, carbonaceous schist, greenstone, and marble, and dikes of Eocene(?) granite porphyry (Prindle, 1907, 1911; Bundtzen, 1981).
The creek is fairly steep, about 400 feet per mile, above an inflection point near its junction with Moose Creek. Two main types of placer deposit have been exploited: alluvial placers along and near modern Friday Creek; and complex fan and terrace gravel deposits mined where Friday Creek enters Moose Creek. The alluvial gravels grade into poorly sorted or unsorted colluvial slope wash deposits along the canyon walls. Slide and colluvial deposits from the sides of the valley locally bury the alluvium, but at places auriferous colluvium on bedrock probably grades into auriferous alluvial valley fill.
The alluvial deposits near modern Friday Creek are 3 to 6 feet thick; pay is in the top of bedrock and in the lowest gravel, totaling about 4 feet thick. Locally, the valley-bottom placer is as much as 100 feet wide, but at one place it narrows to only about 12 feet between bedrock walls (Prindle, 1911, p. 178). Gold recovered from the alluvial deposit was rough, locally almost crystalline. Some was attached to quartz or was accompanied by coarse fragments and boulders of galena and small amounts of stibnite (Brooks, 1907; Prindle, 1911; Cobb, 1973 [B 1374]). Ounce to ounce-and-a-half nuggets were common. Later workers reported pyrite, scheelite, magnetite, and garnet in the concentrates (Levell ,1984, v. 2, mine localities 4 and 17). Gold from Friday Creek was reported to be about 720 fine (Capps, 1919, p. 87, 88). Later studies suggest an average fineness of about 760 (Bundtzen, 1981, table 19).
Complex alluvial fan-terrace deposits occur in the lower part of the creek near its junction with Moose Creek. At one site, alluvial fan sediments from Friday Creek overlie a thin layer of terrace gravels that in turn overlie false bedrock developed on glacial debris (Levell, 1984, v. 2, placer monitoring site 4). The average grade of this deposit was about 0.022 ounce (0.016 fine ounce) of gold per cubic yard. The pay section at the mine included both the terrace gravel and fan material.
The deposits are mainly Holocene. The sources of the gold are auriferous lodes on Quigley Ridge, and, near Moose Creek, low-grade Pleistocene drift.
Geologic map unit (-150.968787172075, 63.5425932000142)
Mineral deposit model Au-PGE placer deposits (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Mainly Holocene.

Production and reserves

Workings or exploration The deposits in Friday Creek were probably discovered in 1905, the major year of placer discovery in the district, and were mined in 1906 (Brooks, 1907; Prindle, 1907). The relatively thin and shallow alluvial deposits were probably exhausted quickly, leaving side pay and probably locally rich colluvial deposits and alluvial fan-terrace deposits to be exploited later. Mining is documented in 1916 and 1922 (Capps, 1919; Davis, 1923); after World War II (Cobb, 1973 [B 1374]); in 1975; and in 1982 and 1983 (Bundtzen, Smith and Tosdal, 1976; Levell, 1984, v. 1 and v. 2).
Indication of production Yes
Reserve estimates No quantified mineable reserves are known, but there are significant resources. There is a small amount of gold left in the alluvium, but the significant resource is in fan-terrace deposits at the mouth of the creek. Mined grades reported from Friday Creek ranged from 0.006 to 0.044 ounce of gold per cubic yard. According to Levell (1984, v. 2), there are about 1,600,000 cubic yards remaining which reasonably could contain between 9,600 and 25,600 fine ounces of gold. This range is determined by the lowest reported grade (0.006 ounce) and the average grade (0.016 ounce) of the deposit when it was mined in 1982 and 1983.
Production notes The amount of gold recovered from Friday Creek is uncertain. Cobb (1980 [OFR 80-363]) estimated total production before 1980 of less than 1000 ounces. This estimate is probably too low. In 1982 and 1983 more than 4000 ounces were recovered, mainly from a fan-terrace deposit; this production included more than 300 ounces recovered from a colluvial-alluvial placer (Levell, 1984). Total production from Friday Creek probably is 5,000 to 10,000 ounces of gold.

Additional comments

The shallow alluvial channel deposits first mined on Friday Creek probably were rich, but small, because of the limited size of the pay section. Placers of moderate grade are in larger, complex fan-terrace deposits at the mouth of the creek. The gold in the alluvial-colluvial deposits has not been transported far; it is accompanied by argentiferous galena, stibnite, and scheelite, which occur in lode deposits drained by the Friday Creek. Some of the placer gold was attached to large chunks of galena, which does not travel far in a placer environment.
The deposit is in Denali National Park and Preserve. It is inactive, except for recreational panning by tourists and park guests.

References

MRDS Number A011270

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.
Heiner, L.E., and Porter, Eve, 1972, Alaska Mineral Properties, volume 2: University of Alaska, Mineral Industry Research Laboratory Report 24, 669 p.
Reporters C.C. Hawley
Last report date 4/21/2001