Brown Bear

Prospect, Inactive

Alternative names

Old Harbor
Silver Queen
Barling Bay

Commodities and mineralogy

Main commodities Ag; Au
Ore minerals arsenopyrite; gold; pyrite; pyrrhotite; sparse tetrahedrite
Gangue minerals chlorite; quartz; sericite

Geographic location

Quadrangle map, 1:250,000-scale KD
Quadrangle map, 1:63,360-scale A-5
Latitude 57.212
Longitude -153.386
Nearby scientific data Find additional scientific data near this location
Location and accuracy This prospect is located 0.3 mile north of triangulation station Love at the head of Barling Bay (Berg and Cobb, 1967, figure 15, locality 13; Cobb, 1972, MF 460, locality 5; McGee, 1972, locality 1; MacKevett and Holloway, 1977, locality 5) Site location is accurate to within 1/4 mile.

Geologic setting

Geologic description

Three separate sulfide-bearing quartz veins, the Brown Bear, Old Harbor, and Silver Queen, cut Cretaceous metasedimentary rock. The Brown Bear vein, said to have been traced for several miles, strikes northeast, generally parallel to bedding. The dip is irregular and varies from 90 to 15 southeast. At one point the vein has a thickness of 15 feet. At another the vein splits into 3 bands 18 inches, 30 inches, and 6 feet in thickness. Assays of nine samples taken by Roehm (1936, PE 131-5) on the Brown Bear vein ranged from trace gold, trace silver over 32 inches to 0.58 ounce per ton gold and 0.30 ounce per ton silver over 12 inches. A basic dike, an aplite dike, and a porphyry dike crop out in the vicinity of the vein.
The Old Harbor vein crops out approximately 400 feet above the Brown Bear. It averages 5 feet in thickness and is said to have been traced for 3000 feet. No descriptions of the Silver Queen vein are available.
Geologic map unit (-153.388254517603, 57.2112171114576)
Mineral deposit model Chugach-type low-sulfide gold-quartz vein (Bliss, 1992; model 36a.1), turbidite-hosted gold vein.
Mineral deposit model number 36a.1
Age of mineralization Cretaceous or younger

Production and reserves

Workings or exploration The Brown Bear vein in 1936 had been developed by a 42-foot adit, a 23-foot adit and several open cuts. Open cuts and pits exposed some of the other veins. Nine samples taken by Roehm (1936, PE 131-5) on the Brown Bear vein assayed from trace gold and silver over 32 inches to 0.58 ounce per ton gold and 0.30 ounce per ton silver over 12 inches.
Indication of production Undetermined

Additional comments

Most of the area is on land conveyed to the Koniag Corporation.

References

MRDS Number A015092

References

Reporters S.H. Pilcher (Anchorage)
Last report date 10/12/1998