Upper McCumber Creek

Prospect, Inactive

Commodities and mineralogy

Main commodities Au
Ore minerals gold
Gangue minerals garnet; magnetite

Geographic location

Quadrangle map, 1:250,000-scale MH
Quadrangle map, 1:63,360-scale C-4
Latitude 63.7061
Longitude -145.5792
Nearby scientific data Find additional scientific data near this location
Location and accuracy This placer prospect is at an elevation of 2,700 on upper McCumber Creek in the NW1/4NE1/4 section 15, T. 14 S, R. 11 E., Fairbanks Meridian. It corresponds to locality 3 of Cobb (1979 [OFR 79-238]) and locality N2 in table 3 of Nokelberg and others (1991). The location is accurate within a mile.

Geologic setting

Geologic description

In the McCumber Creek area small amounts of gold occur in alluvial gravel in streams draining an area of extensive glacial deposits (Smith, 1932). The gravel consists mainly of metasedimentary schists (Nokleberg and others, 1991). The most common bedrock types in the area are quartz-mica schist and quartz-rich phyllite; sulfide-bearing cobbles and quartz float are common (T. Hinderman, written communication, 1986). The schist is cut by diabase dikes and is overlain by conglomerate of the Nenana Gravel of Tertiary age, which is considered to be the source of placer gold in other districts in central Alaska (T. Hinderman, written communication, 1986). Gold recovered by T. Hinderman from Morningstar Creek in 1986 was flat and contained minor inclusions of silver. Most of the minerals accompanying the gold were garnet and magnetite.
Geologic map unit (-145.581485372527, 63.7057012165596)
Mineral deposit model Placer Au (Cox and Singer, 1986; model 39a).
Mineral deposit model number 39a
Age of mineralization Holocene.

Production and reserves

Workings or exploration Mining claims on McCumber Creek recorded in 1954 reportedly were idle in 1974 (Mulligan, 1974). In 1986 the McCumber Morningstar Property consisted of 40 State claims controlled by Richard Knudsen of Anchorage (T. Hinderman, written communication, 1986). A placer test completed in 1986 resulted in the owner allowing the claims to lapse. The test showed a resource in lower Morningstar Creek of 128,000 cubic yards of gravel grading $4.83 (0.019 ounce of gold) per cubic yard. McCumber Creek contains a much larger, lower-grade resource of 1,200,000 cubic yards of gravel grading $1.18 (0.0045 ounce of gold) per cubic yard.
Indication of production Yes; small

References

References

Reporters W.T. Ellis (Alaska Earth Science), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (USGS)
Last report date 8/14/2002