McCaskey Bar

Mine, Inactive

Commodities and mineralogy

Main commodities Au
Other commodities Hg
Ore minerals cinnabar; gold; ilmenite; magnetite

Geographic location

Quadrangle map, 1:250,000-scale TN
Quadrangle map, 1:63,360-scale A-1
Latitude 65.16753
Longitude -150.21308
Nearby scientific data Find additional scientific data near this location
Location and accuracy
McCaskey Bar is a bench between Eureka and Kentucky Creeks. The site is at the mine symbol on the east side of Eureka Creek, in the southwest quarter of section 16, T. 4 N., R. 13 W., of the Fairbanks Meridian. According to Cobb (1972, location 42; 1977), the area of placer mining extends eastward from the mine symbol for about a mile. The western edge of the placer mine is apparently within a quarter mile of a landing strip to the northwest. The location is accurate within half a mile.
This site is approximately 0.5 mile west of the site for McCaskey Bar, U.S. Bureau of Land Management MAS number 0020480048.

Geologic setting

Geologic description

Bedrock in the area of the McCaskey Bar placer deposit consists of Jurassic or Cretaceous clastic sedimentary strata that are cut by thrust faults and locally intruded by one or more dikes of unknown composition (Chapman and others, 1982; Reifenstuhl and others, 1998). Mertie (1934) described the bedrock in the mined area as altered phyllite and argillite, often so decomposed that no hard rock could be found. A dike that cuts the country rock is just as altered, and quartz veins in the bedrock are also decomposed and iron-stained.
Mertie (1934) described McCaskey Bar as an old terrace placer east of Eureka Creek, approximately 250 feet above the active stream channel. The gold appears to be concentrated in the upper foot or so of the bedrock, but minor amounts also occur throughout the gravels in streaks at least 100 feet wide. Mertie reported the fineness of gold in one sample as 802.75. The largest nugget reported as of 1931 was worth $8.00 (gold at $20.67 per ounce). The heavy mineral concentrates contained ilmenite, picotite, cinnabar, and magnetite (Waters, 1934).
Mining has been mainly by hydraulicking the frozen overburden and allowing the ground to thaw naturally. Water is scarce in summer and mining was intermittent (Mertie, 1934). Cobb's (1977) and Smith's (1933) reports of Farmer & Jones operating a hydraulic mine in 1928 in the Eureka Creek area actually refer to an operation on McCaskey Bar (Wimmler, 1926). Ray C. Pittman operated a bulldozer just south of McCaskey Bar on Eureka Creek in 1975 (Carnes, 1976).
Geologic map unit (-150.215561490869, 65.1670523837628)
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 McCaskey Bar was mined by hydraulic methods and sluicing starting in 1924 and continued through the 1930s (Mertie, 1934). Cobb's (1977) and Smith's (1933) reports of Farmer & Jones operating a hydraulic mine in 1928 in the Eureka Creek area actually refer to an operation on McCaskey Bar (Wimmler, 1926, 1930). Ray C. Pittman operated a bulldozer just south of McCaskey Bar on Eureka Creek in 1975 (Carnes, 1976).
Indication of production Yes; small
Production notes No official records of production from McCaskey Bar have been made public.

References

MRDS Number A015222

References

Bottge, R.G., 1986, Maps summarizing land availability for mineral exploration and development in northcentral Alaska, 1985: U.S. Bureau of Mines Open-File Report 70-86, 14 sheets.
Reporters G.E. Graham (ADGGS)
Last report date 12/10/2000