Lake Creek

Mine, Active?

Commodities and mineralogy

Main commodities Au
Other commodities As; Bi; Cu; Pt; Sb; W
Ore minerals bismuth; bismuthinite; copper; galena; gold; hematite; magnetite; platinum; pyrite; scheelite; stibnite

Geographic location

Quadrangle map, 1:250,000-scale WI
Quadrangle map, 1:63,360-scale B-4
Latitude 67.475
Longitude -151.5518
Nearby scientific data Find additional scientific data near this location
Location and accuracy Lake Creek enters the southeast end of Wild Lake about 0.5 mile north of its south end. Lake Creek has mainly been mined from about 0.5 miles to about 1.5 miles above its mouth. The center of the mined area is about 0.6 mile north-northwest of the center of section 34, T. 31 N., R. 18 W. The location is accurate.

Geologic setting

Geologic description

Gold was discovered on Lake Creek in 1903 (Maddren, 1910; 1913) and mining continued intermittently to at least 2001 (Kurtak and others, 2002, Eden, 2004; Brooks Range Exploration, 2012). Most of the gold has been produced near the head of an alluvial fan at the mouth of Lake Creek and in a narrow portion of the creek valley about 1.5 miles from its mouth. Near the head of the alluvial fan, the depth to bedrock is 60 to 95 feet; in the upper valley of the creek, the depth to bedrock is only 3 feet. Reed (1938) reported that production from the mining from 1904 to 1937 was at least $26,000 (about 1,300 ounces of gold) but he speculated that the extent of the workings indicated that the production was many thousands of dollars more. Kurtak and others (2002) report that the creek produced 2,624 ounces of gold in twelve years from 1903 to 1955. Mining before WWII was mainly by hand methods, ground sluicing, and in the upper part of the alluvial fan by drifting. In 1999, a large wash plant was built to mine ground at the upper part of the fan with mechanized equipment. The mining in the late 1990s revealed that there were two distinct bedrock channels underneath the upper portion of the fan and that they they extend upstream from the top of the fan. Incomplete records indicate that at least 1,314 ounces of gold were produced from 1995 to 2001.
The rocks in the area are predominantly Devonian muscovite-chlorite schist that contains numerous quartz lenses and veinlets (Kurtak and others, 1999). Some of the quartz is parallel to the cleavage or schistosity, and transects it. Reed (1938) describes the bedrock about 200 feet above the last of the old workings (about 2 miles from the lake) as alternating micaceous and graphitic schist cut by a 300-foot-wide, greenstone dike. This greenstone dike was not observed by Kurtak and others (1999). Reed (1938) also noted soft reddish schist containing numerous quartz stringers at the head of Lake Creek.
The gravels on Lake Creek are coarse and waterworn with numerous large schist boulders. The upper part of the gravel contains erratics of conglomerate and black chert. The gold occurs as coarse, waterworn nuggets, and also as fine flour gold. Maddren (1913) noted recovery of nuggets valued at $90 to $150 (about 4.7 to 7.9 ounces). A 22-ounce nugget was recovered in 1995 and a 24.25-ounce nugget was recovered in 1996 (Kurtak and others, 2002).
Smith and Mertie (1930) reported that the concentrates from the placers along Lake Creek had a high content of scheelite. Joesting (1943) lists several minerals in the placer concentrates from Lake Creek, including inch-long pieces of stibnite, scheelite, native bismuth, native copper, hematite, pyrite and magnetite. Sluice concentrates collected by Kurtak and others (1999) contained up to 5,930 parts per billion (ppb) platinum, 976 parts per million (ppm) tungsten, 0.44 percent bismuth, 1,750 ppm arsenic, and 3,043 ppb gold. The sluice concentrates did not contain visible gold. Miners also showed them nuggets of bismuthinite said to come from Lake Creek. Samples of quartz from the placers thought to be from veins contained up to 8,631 ppm copper and 62 ppb gold.
Kurtak and others (2002) and Blakestad (2003) suggest that there is moderate potential for placer gold in the central basin of Lake Creek from the alluvial fan beside Wild Lake upstream to the canyon narrows. The north channel of the creek and possible bench channels to the south of the creek have not been evaluated. Based on an unpublished report by Blakestad (2000), Kurtak and others (2002) give an 'indicated resource' of 10,087 ounces of gold in Lake Creek.
Geologic map unit (-151.554549819008, 67.4745478239333)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration Intermittent mining by hand methods, sluicing and drifting from 1904 to the the 1990s. In 1999, a large washing plant was built to mine gravels at the top of the alluvial fan above the mouth of Lake Creek with mechanized equipment (Kurtak and others, 2002). Mining continued until at least 2001.
Indication of production Yes; small
Reserve estimates Kurtak and others (2002) and Blakestad (2003) suggest that there is moderate potential for placer gold in the central basin of Lake Creek from the alluvial fan beside Wild Lake upstream to the canyon narrows. The north channel of the creek and possible bench channels to the south of the creek have not been evaluated. Based on an unpublished report by Blakestad (2000), Kurtak and others (2002) give an 'indicated resource' of 10,087 ounces of gold in Lake Creek.
Production notes Reed (1938) reported production from early mining from 1904 to 1937 to be at least $26,000 (about 1,300 ounces of gold) but he speculated that the extent of the workings indicated that the production was many thousands of dollars more. Kurtak and others (2002) tabulated the production by year from 1903 to 2001. From 1903 to 1955, the placers on Lake Creek produced 2,624 ounces of gold in 12 years. Another 1,314 ounces of gold was produced from 1955 to 2001 but the records are incomplete. The total production from 1903 to 2001 was thus at least 3,938 ounces of gold.

References

MRDS Number A011021; D002540

References

Blakestad, R.A., 2003, Wild Lake Creek resources summary:
Brooks Range Exploration II, LLC, 2012, Brooks Range Exploration II: http://www.brooksrangeexploration.com/General_Info.html (as of February 22, 2012).
Eden, Harsten, 2004, Report on a visit to the Wild Lake-Lake Creek area in the central Brooks Range, Alaska: http://www.brooksrangeexploration.com/images/FULL%20EDEN%20REPORT.pdf, 16 p. (as of February 22, 2012)
http://www.brooksrangeexploration.com/images/Wild%20Lake%20Creek%20Blakestad%20Report%202003.pdf, 9 p. (as of February 22, 2012).
Kurtak, J.M., Klieforth, R.F., Clark, J.M., and Maclean, E.A., 2002, Mineral investigations in the Koyukuk mining district, northern Alaska: Final Report: U.S. Bureau of Land Management Technical Report 50, v. 1 and 2, 845 p.
Reporters J.M. Britton (Anchorage); D.J. Grybeck (Contractor, USGS)
Last report date 4/1/2012