Indian

Prospect, Inactive

Alternative names

Blue Ridge

Commodities and mineralogy

Main commodities Ag; Au; Cu; Pb
Ore minerals azurite; chalcopyrite; galena; malachite; pyrite; tetrahedrite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale GU
Quadrangle map, 1:63,360-scale D-1
Latitude 62.82
Longitude -144.22
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Indian or Blue Ridge prospect is about one mile northwest of the west end of Long Lake at an elevation of about 5,100 feet. The coordinates are the site of a vein exposed on the ridge; it is at the center of a mineralized area which is mainly in the SE1/4, section 14, T. 12 N., R. 6 E., Copper River Meridian. The prospect is at locality 5 of Richter and Matson (1972), and locality 5 of MacKevett and Holloway (1977).

Geologic setting

Geologic description

The Indian prospect is mainly in relatively coarse and dark-colored, quartz monzonite of the Pennsylvanian to Permian, Ahtell pluton. It lies within a few hundred feet of its contact with Pennsylvanian to Permian, Tetelna volcanic rocks which are exposed to the south. The contact between the two units is a fault which strikes northwest. The fault zone is filled with a barren quartz vein that can be followed for more than 1,000 feet (Richter, 1966, p. 30; Thorne, 1946, fig. 2).
The area was first described by Moffit (1932) who visited the area in 1929. The prospect was restaked by Carl Witham and was examined by Thorne of the U. S. Bureau of Mines (Thorne, 1946) in company with Witham. Thorne made a sketch map of the property. Their map (figure 2) is the best available for the property.
In addition to the barren quartz vein, Thorne found five other veins. Thorne (1946, table 1) collected three samples from an east-west striking vein on the Blue Ridge No. 2 claim. This vein is exposed in pits on the west side of the ridge and about 150 feet north of the fault contact of the Ahtell pluton and Tetelna volcanics. Sample 1 from a 2-foot-thick vein that contains galena, chalcopyrite, tetrahedrite, and secondary azurite and malachite in quartz-calcite gangue, assayed 0.01 ounce of gold per ton, 11.44 ounces of silver per ton, 4.18 percent lead, and 1.44 percent copper. Thorne's sample 2 was low grade, partly because of dilution with barren soil. Sample 3 of a 1-foot vein contained 5.16 ounces of silver per ton, 6.81 percent lead, and some copper. The veins are crustified and the sulfides fill open spaces in the crystalline quartz.
A narrow vein exposed about 4000 feet to the east of the barren quartz vein on the Blue Ridge No. 5 claim contained 0.04 ounce of gold per ton, 15.56 ounces of silver per ton, and 19.92 percent lead. Another vein exposed on the ridge on the end line between the Blue Ridge Nos. 5 and 1 claims contains 5.24 percent lead and small amounts of gold and silver.
The area was visited later by Richter (1966) but the trenches excavated by Witham and Thorne were caved. One vein that remained exposed was 5 feet thick, has a strike of N84W and dips 86 degrees south. It is mainly massive quartz with some galena and copper-staining. Wedow and others (1953) and Nelson, West, and Matzko (1954) found no appreciable uranium in the veins.
Geologic map unit (-144.222199803588, 62.8196053147586)
Mineral deposit model Polymetallic vein? (Cox and Singer, 1986; model 17?).
Mineral deposit model number 17?
Age of mineralization Emplaced subseqent to or is related to the border phase of the Pennsylvanian to Permian, Ahtell pluton.

Production and reserves

Workings or exploration The area was active when visited by Moffit in 1929 (Moffit, 1932). The prospect was again active late in World War II when it was examined by Thorne (1946) with the then-current owner, Carl Witham. The only workings are hand-dug open cuts.
Indication of production None

Additional comments

Additional information can be obtained from Ahtna Minerals in Anchorage, Alaska.

References

MRDS Number A011838

References

Reporters W.T. Ellis (Alaska Earth Sciences), C.C. Hawley (Hawley Resource Group), and W.J. Nokleberg (U.S. Geological Survey)
Last report date 11/30/2000