Glen Creek

Mine, Inactive

Alternative names

Glenn Creek

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Mn; Pb; Sb; Sn; W
Ore minerals cassiterite; galena; gold; pyrite; rhodonite; scheelite; stibnite
Gangue minerals garnet; ilmenite; magnetite

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale C-2
Latitude 63.5465
Longitude -150.7095
Nearby scientific data Find additional scientific data near this location
Location and accuracy Glen Creek (Cobb, 1980 [OFR 80-363]) drains the south flank of the Kantishna Hills between Rainy Creek and Dry Creek to the west and Spruce Creek to the east. The West Fork of Glen Creek rises on Glacier Peak; the East Fork drains an unnamed ridge west of Spruce Peak. The location is at the approximate midpoint of the main productive part of Glen Creek, about a mile below the junction of the East and West Forks. The location is accurate. Glen Creek is location 51 of Cobb (1972 [MF 366]) and location 56 of MacKevett and Holloway (1977). As defined here, Glen Creek includes resource blocks GL-1 and GL-2 of Levell (1984 [v. 2]).

Geologic setting

Geologic description

Both West Fork and East Fork of Glen Creek are cut in semischist, phyllite, metafelsite, and related rocks of the lower Paleozoic Spruce Creek sequence (Hawley and Associates, 1978; Bundtzen, 1981; Thornsberry, McKee, and Salisbury, 1984, fig. K-2). Below the junction of East and West Forks, Glen Creek flows through a canyon cut into Birch Creek Schist. The creek then flows for about a mile over glacial till and outwash sediments, to its confluence with Moose Creek
The gradient of Glen Creek is fairly steep. In the main drainage, from the mouth of the creek to the junction of East and West Forks, it is about 200 feet to the mile. The gradient of West Fork is 400 feet to the mile; East Fork generally has a lower gradient, but is steep in the upper canyon.
Gold was discovered in Glen Creek in 1905 or 1906, and was mined as early as 1906. Initially, gravel in the main canyon was mined. This gravel was up to three feet thick and 30 to 150 feet wide. Gravel at the junction of East and West Forks is locally much thicker than that mined in the main canyon or in East Fork. Capps (1919) reported gravel more than 34 feet thick at the junction, and Levell (1984, v. 2) monitored an operation near the forks where the alluvium was 35 or more feet thick. The gold generally occurred on bedrock or in the lowermost two feet of gravel; some occurred in fractured bedrock. The gold was relatively coarse; maximum nugget size was about three ounces (Prindle, 1907, 1911). In 1916, the creek was mined from, or just above, the forks to a point about 2 miles downstream (Capps, 1919, fig. 6). On claim No. 9, the gravels were 5 to 8 feet thick; they were bouldery and contained large slabs of schist. Nugget gold was discolored; fine gold was bright; fineness ranged from about 725 to 764 (Capps, 1919, p. 84). The gold was rough and some was attached to pebbles of galena and to pebbles and small boulders of rhodonite. Concentrates contained pyrite, magnetite or ilmenite, and garnet, locally accompanied by cassiterite, scheelite, and stibnite. The cassiterite was reported in a sample submitted to the Territorial Department of Mines in 1927 by Arthur W. Lilliedale (Joesting, 1941-43; Wells, 1933, p. 372). Stibnite and scheelite, along with galena, pyrite, magnetite, and rhodonite were reported from an operation at the forks, and from one in East Fork (Levell, 1984, v. 2). All of the valuable accessory minerals, except rhodonite and cassiterite, occur in lode deposits drained by Glen Creek. Rhodonite is especially abundant in the placer gravels near MM058. Some of it is of gem quality.
The calculated ore grade at two operations in 1983 was about 0.015 fine ounce of gold per cubic yard (Levell, 1984, v. 2). Other tests showed grades as low as 0.0027 ounce of gold per cubic yard in potentially mineable sections. Locally, the ground was much richer, and Glen Creek produced a high proportion of nugget gold that sold at a premium price.
Geologic map unit (-150.711779917402, 63.5459991704991)
Mineral deposit model Au-PGE placer (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Holocene.

Production and reserves

Workings or exploration Mining began in Glen Creek as early as 1906, and it was being mined in 1916 (Prindle, 1907; Capps, 1919). There were three operations on the creek in 1922 (Davis, 1923). Cobb (1980 [OFR 80-363]) indicates that the creek was mined or prospected in most years between 1920 and 1939. The creek was mined after World War II. Bundtzen, Smith and Tosdal (1976) reported operations in 1975, and there were two operations in 1983 (Levell, 1984, v. 2). There has been little if any mining since 1985.
Indication of production Yes; small
Reserve estimates
Levell (1984, v. 2) estimated about 480,000 cubic yards of stream alluvium in East and West Forks of Glen Creek and overlying the schist bedrock part of the creek below the forks (resource block GL-1). Test results ranged from 0.0043 ounce of gold per cubic yard in a small sample, to 0.015 ounce of gold per cubic yard in two monitored tests in 1983. The range in calculated gold resource is between 2,064 and 7,200 fine ounces of gold. The upper value in the range seems conservative; Levell (1984) reported that samples from nearby unmonitored cuts indicated considerably higher values.
A larger but less certain resource exists in about 1,900,000 cubic yards of bench gravel in resource block GL-1. Results of small-scale tests showed 0.0027 to 0.0093 ounce of gold per cubic yard. Using these values, the calculated gold resource is 5,130 to 17,670 fine ounces of gold.
Resource block GL-2 consists of the approximately mile-long section of Glen Creek that flows on an alluvial fan and, probably, on glacial outwash. The resource is high-potential stream alluvium; test results ranged from 0.0063 to 0.0228 ounce of gold per cubic yard. This possible gold resource ranges from 1,575 to 5,700 fine ounces of gold.
Production notes Total production from Glen Creek is unknown. Cobb (1980 [OFR 80-363]) estimated it to be 1,000-10,000 fine ounces of gold. Levell (1984, v. 2) reported recovery in 1983 of about 216 ounces from two mining operations during monitored cleanups. Each of these operations probably produced about 1,000 ounces per year. Minimum total production from Glen Creek is probably at least 5,000 fine ounces of gold.

Additional comments

Numerous lode deposits in the upper East and West Forks of Glen Creek shed gold, stibnite, galena, pyrite, and scheelite into Holocene placer deposits in the creek. Diligent prospecting would probably locate the source of the cassiterite and rhodonite. Glen Creek is in Denali National Park and Preserve.

References

MRDS Number A011272

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 4/27/2001