Graham and Harrison

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu
Ore minerals chalcopyrite; pyrrhotite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale SR
Quadrangle map, 1:63,360-scale B-2
Latitude 60.2703
Longitude -147.7363
Nearby scientific data Find additional scientific data near this location
Location and accuracy The prospect is located at 1,300 feet elevation in a saddle southeast of peak 1995, in the divide that separates the head of Snug Harbor from Montague Strait. It is in the NW1/4 section 16, T. 2 N., R. 10 E., of the Seward Meridian. This is location 238 of Cobb and Tysdal (1980) and location S-40 of Jansons and others (1984). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

The prospect consists of veins and layers of disseminated sulfides within several hundred feet of brecciated and schistose sheeted dikes of the Orca Group of early Tertiary age (Cobb and Tysdal, 1980). The sulfide minerals are exposed in two open cuts driven along a N 45 E-trending shear zone. The zone dips from vertical to 80 SE (Kurtak and Jeske, 1986). The exposed sulfides consist mainly of disseminated pyrrhotite and chalcopyrite blebs along cleavage planes (Kurtak and Jeske, 1986). Grant and Higgins (1909) examined hand samples from a reported 1- to 4-foot-wide quartz vein on the prospect that contained pyrrhotite and chalcopyrite.
A random chip sample from one of the open cuts contained 1.4 percent copper and 20 ppm silver (Kurtak and Jeske, 1986).
Geologic map unit (-147.738350019231, 60.2697345382117)
Mineral deposit model Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Mineral deposit model number 24a
Age of mineralization Tertiary or younger; the occurrence is in rocks of the Orca Group of Tertiary age.
Alteration of deposit Basalt is altered to greenstone.

Production and reserves

Workings or exploration There are two open cuts on the prospect; their size is unknown. Grant and Higgins (1909) described a 60-foot adit in the area, but the U.S. Bureau of Mines did not find it when they visited the prospect in the early 1980s. A chip sample was collected from the shear zone exposed in one of the open cuts. It contained 1.4 percent copper and 20 ppm silver (Kurtak and Jeske, 1986).
Indication of production None

References

MRDS Number A010397

References

Reporters Jeff A. Huber and Carol S. Huber (Anchorage)
Last report date 11/9/2001