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Ibach

Prospect, Inactive

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Alternative names

The Sure Thing 1906

Commodities and mineralogy

Main commodities Ag; Cu; Pb; Zn
Ore minerals chalcopyrite; pyrite; pyrrhotite; sphalerite

Geographic location

Quadrangle map, 1:250,000-scale CV
Quadrangle map, 1:63,360-scale C-4
Latitude 60.657
Longitude -145.386
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of about 2100 feet on the east wall of Ibeck Creek approximately 2.5 miles north of the toe of Scott Glacier. It is in the N1/2 sec. 15, T. 14 S., R. 1 W., of the Copper River Meridian. Location accurate to within 1000 ft. Location corresponds to site C-17 in Jansons and others (1984).

Geologic setting

Geologic description

This prospect is hosted in a unit of the Tertiary Orca Group consisting mostly of tabular or lenticular bodies of mafic volcanic rocks, including pillowed or massive flows, breccia and dikes (Nelson and others, 1985). Grant and Higgins (1910) reported a vein 12-20 feet wide and two miles long in the area. Jansons and others (1984) reported a 14-foot-wide shear zone in volcanic rock containing small lenses of pyrite, pyrrhotite, chalcopyrite, and sphalerite. U.S. Bureau of Mines sampling and analysis (Jansons and others, 1984) in the area yielded the following results from five chip samples: 4 ppm to 3.4% Cu, 40 ppm to 1.95% Zn, 10 ppm to 0.26% Pb, and 3.6 to 11 ppm Ag. Four grab samples contained 0.52 to 5.5% Cu, 215 ppm to 2.4% Zn, 30 ppm to 0.28% Pb, and 0.4 ppm to 14 ppm Ag.
Geologic map unit (-145.387987759596, 60.65646770709)
Mineral deposit model Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Mineral deposit model number 24a
Age of mineralization Probably Tertiary based on the age of the host rocks.
Alteration of deposit Surface oxidation.

Production and reserves

Workings or exploration Workings consist of an 80-foot-long adit. U.S. Bureau of Mines sampling and analysis (Jansons and others, 1984) in the area yielded the following results from five chip samples: 4 ppm to 3.4% Cu, 40 ppm to 1.95% Zn, 10 ppm to 0.26% Pb, and 3.6 to 11 ppm Ag. Four grab samples contained 0.52 to 5.5% Cu, 215 ppm to 2.4% Zn, 30 ppm to 0.28% Pb, and 0.4 ppm to 14 ppm Ag.
Indication of production None
Reserve estimates Inferred reserves are estimated at 3,800 tons @ 2.8% Cu, 2.2% Zn, and 10 ppm Ag (Garret, 1971).

Additional comments

Ibeck Creek is (mis)named for Joe(?) Ibach, an early prospector in the area. Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.

References

MRDS Number A010424

References

Garrett, C.R., Jr., 1971, Report of mineral examination-Hartney Bay: U.S. Department of Agriculture, Forest Service, Alaska Region, Report R10-26, 14 p.
Grant, U.S., and Higgins, D.F., Jr., 1910, Reconnaissance of the geology and mineral resources of Prince William Sound, Alaska: U.S. Geological Survey Bulletin 443, 89 p.
Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, southcentral Alaska: U.S. Bureau of Mines Mineral Land Assessment 5-84, 218 p., 2 sheets, scale 1:250,000.
Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.
Reporters S.W. Nelson, Anchorage, AK
Last report date 6/10/2000