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Slope Creek

Mine, Inactive

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Commodities and mineralogy

Main commodities Au
Other commodities Ag; Bi; Cu
Ore minerals gold; magnetite; native copper; silver; unidentified bismuth mineral

Geographic location

Quadrangle map, 1:250,000-scale NB
Quadrangle map, 1:63,360-scale D-6
Latitude 62.7879
Longitude -143.9914
Nearby scientific data Find additional scientific data near this location
Location and accuracy This placer mine is on Slope Creek, a west tributary to Porcupine Creek. It is at an elevation of about 3,600 feet, about 1.1 miles upstream from Porcupine Creek. It is close to the west boundary of the Nabesna D-6 quadrangle in the SW1/4 of section 30, T. 12 N., R. 8 E. of the Copper River Meridian. This is locality 58 of Richter and others (1975). Slope Creek is not named on the USGS Nabesna D-6 quadrangle (revised 1969) but it is clearly located by Richter (1966) and Richter and Matson (1968). This mine was included by Cobb and Richter (1980) under the name 'Slope Cr.'. The map location is accurate to within a few hundred feet. Note that Richter (1964) identified Slope Creek as Boulder Creek, and Cobb and Richter (1980) note that confusion exists between these two nearby creeks in several early reports. Richter's (1966) location for Slope Creek is followed in this record.

Geologic setting

Geologic description

A small amount of gold was recovered from this placer mine on upper Slope Creek. The gold is fine, rough, and accompanied by wire silver, native copper, a bismuth mineral, and magnetite (Moffit, 1944; 1954). Bedrock in Slope Creek is dominantly andesitic volcanic rocks of the upper Paleozoic Tetelna Volcanics (Richter, 1976) but felsic plutonic rocks of the Ahtell pluton are exposed about 1 mile to the west. The andesitic rocks are cut by an east-west trending fault at the head of Slope Creek (Richter, 1966, figure 2).
Geologic map unit (-143.993590926735, 62.7875115118721)
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 Small-scale surface placer workings are present.
Indication of production Yes; small
Production notes Production was probably less than 500 ounces (Cobb and Richter, 1980).

References

MRDS Number A011427

References

Cobb, E.H., and Richter, D.H., 1980, Summaries of data on and list of references to metallic and selected nonmetallic mineral deposits in the Nabesna quadrangle, Alaska: U.S. Geological Survey Open-File Report 80-927, 117 p.
Moffit, F.H., 1944, Mining in the northern Copper River region, Alaska: U.S. Geological Survey Bulletin 943-B, p. 25-47.
Moffit, F.H., 1954, Geology of the eastern part of the Alaska Range and adjacent area: U.S. Geological Survey Bulletin 989-D, p. 65-218.
Richter, D.H., 1964, Geology and mineral deposits of the Ahtell Creek area, Slana district, southcentral Alaska: Alaska Division of Mines and Minerals Geologic Report 6, 18 p., 1 sheet, scale 1:31,680.
Richter, D.H., 1966, Geology of the Slana district, southcentral Alaska: Alaska Division of Geological and Geophysical Surveys Geological Report 2l, 54 p., 3 sheets, scale 1:63,360.
Richter, D.H., 1976, Geologic map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Investigations Series Map I-932, 1 sheet, scale 1:250,000.
Richter, D.H., and Matson, N.A., 1968, Distribution of gold and some base metals in the Slana area, eastern Alaska Range, Alaska: U.S. Geological Survey Circular 593, 20 p.
Richter, D.H., Singer, D.A., and Cox, D.P., 1975, Mineral resources map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-655-K, 1 sheet, scale 1:250,000.
Reporters Travis L. Hudson (Applied Geology)
Last report date 11/24/2002