Porphyry Mountain

Prospect, Inactive

Commodities and mineralogy

Main commodities Au; Mo
Other commodities As; Cu; W
Ore minerals chalcopyrite; molybdenite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MC
Quadrangle map, 1:63,360-scale B-5
Latitude 61.4426
Longitude -142.8323
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is at an elevation of 4,000 feet on the southwest flank of Bonanza Ridge. It is 9,500 feet south of Porphyry Mountain and 3,000 feet west-southwest of elevation 6309 in the SE1/4 of 11, T. 5 S., R 14 E. of the Copper River Meridian. This is locality 77 of MacKevett (1976); the location is accurate to within a few hundred feet.

Geologic setting

Geologic description

The deposit at this prospect consists of a discontinuous quartz vein up to 20 inches thick with molybdenite and minor chalcopyrite that is localized along a fault that cuts Tertiary granodiorite (MacKevett, 1976). The molybdenite occurs along the vein selvages. Samples contain as much as 200 parts per million (ppm) arsenic, 2.4 ppm gold, 100 ppm tungsten, and more than 2,000 ppm molybdenum (MacKevett and Smith, 1968). The deposit was explored by about 400 feet of underground workings.
Geologic map unit (-142.834370078951, 61.4421624245099)
Mineral deposit model Vein
Age of mineralization Tertiary based on the age of the granodiorite host rock (MacKevett, 1974).

Production and reserves

Workings or exploration The deposit was explored by about 400 feet of underground workings.
Indication of production None

Additional comments

The locality is in the Wrangell-Saint Elias National Park and Preserve.