Upper Dahl Creek

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Cd; Cr; Cu; nephrite
Ore minerals gold; native silver

Geographic location

Quadrangle map, 1:250,000-scale SH
Quadrangle map, 1:63,360-scale D-2
Latitude 66.9755
Longitude -156.8592
Nearby scientific data Find additional scientific data near this location
Location and accuracy The upper Dahl Creek placer mine extends along the creek from just below Wye Creek to just above Harry Creek. The coordinates are for the mine symbol at the confluence of Wye Creek. The deposit is in sections 3 and 10, T. 18 N., R. 9 E., of the Kateel River Meridian. Cobb (1972, MF-448), locations 13, 14.

Geologic setting

Geologic description

At the upper Dahl Creek placer mine most of the gold lies on, or just above, bedrock, although some spongy gold occurs in black, soil-like overburden (A. Williams, unpublished data, 1998). The gold was most abundant near the mouth of Wye Creek. Creek gravels range from 5 to 25 feet thick. The gold is in the lower 1 to 2 feet of gravel as well as on bedrock; it is unevenly distributed and patchy, occurring in pockets. There is no continuous pay streak. The gold is reddish to brass yellow in color. Some of the nuggets were spongy and rare wire gold has been reported. Nuggets of considerable size have been recovered from the deposit. One nugget was worth about $65 in 1913 and had considerable greasy-looking milky quartz attached. A flat nugget worth over $600 was recovered just below Harry Creek. The gold was valued at $17.20 per ounce (Reed, 1931). Concentrates from the placers are predominately magnetite, along with some chromite and native copper. Nuggets of native silver up to 1 inch in diameter been reported in the concentrates. The silver carries a small amount of cadmium. (Smith, 1913). Nephrite boulders have been recovered during placer mining.
The upper Dahl Creek placer is in thawed ground. Bedrock is lower Paleozoic, black slate with quartz stringers, and schist which breaks into small, rectangular blocks. The joint faces on these blocks are commonly iron-stained. The dominant strike of the bedrock is perpendicular to the creek, forming natural riffles for catching gold. Holes sunk on some low benches on either side of the creek are in unconsolidated deposits up to 15 feet thick. Quartz veins cutting bedrock on these benches are 1 inch to 4 feet thick. Serpentinite near Dahl Creek around the confluence of Stockley Creek contains chrysotile and fibrous serpentine.
Geologic map unit (-156.861932213173, 66.9749510759532)
Mineral deposit model Placer Au-PGE (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Quaternary.

Production and reserves

Workings or exploration Gold was first discovered in 1898 and the claims were worked more or less continuously up to 1968. From the late 1950s into the early 70s nephrite boulders were recovered and cut during the mining process. Early mining was done with shovels and sluice box. In the 1920s, hydraulic equipment was installed and used extensively around Wye Creek. In 1988 and 1989 NANA took jig samples from each of the claim blocks in an attempt to complete a patenting application on the claims.
Indication of production Yes; small
Production notes Total production from the Dahl Creek placers (also see ARDF number SH002) is estimated to be 15,000 ounces to more than 17,000 ounces (Degenhart and others, 1978).

Additional comments

The gradient of Dahl Creek is approximately 150 feet per mile. Much of material collected as nephrite jade was serpentinite rather than nephrite. Best placer ground is worked out. The mine area is accessible by trail from Kobuk and is owned by NANA Regional Corp. Data on Dahl Creek are available by request from NANA Regional Corp.

References

MRDS Number A015601

References

WGM Staff, 1980, Non-fuel mineral resources of Alaska: Anchorage, Alaska, WGM, Inc. Unpublished report for Phillips Petroleum Company, 320 p. (Report held by NANA Regional Corporation, Anchorage, Alaska).
Reporters Anita Williams (Anchorage, AK)
Last report date 12/16/1999