Blue Bonanza

Mine, Inactive

Alternative names

Midnight Sun

Commodities and mineralogy

Main commodities Au
Other commodities Ag; Pb; Sb
Ore minerals arsenopyrite; galena; gold; stibnite; tetrahedrite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale FB
Quadrangle map, 1:63,360-scale D-3
Latitude 64.891
Longitude -148.06
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Blue Bonanza mine is located in the NW1/4NE1/4 sec. 25, T. 1 N., R. 3 W., Fairbanks Meridian. This mine is on the divide between Sheep Creek and Nugget Creek at an elevation of about 1,900 feet. It is about 0.7 mile north of the top of Ester Dome. The mine is locality 8 of Cobb (1972 [MF 410]).

Geologic setting

Geologic description

Ore was mined from a rich quartz vein that was 18 inches thick at the surface and narrowed with depth. Two periods of vein formation have been described. The older quartz is crushed and has cavities, whereas the younger quartz has glassy crystals and is banded parallel to walls (Smith, 1913 [B 525]). Gold is visible both near and remote from sulfides. The sulfides are galena, pyrite, and some stibnite; considerable silver is present in tetrahedrite. By 1914, a shaft was driven to a depth of 130 feet; however, the richest ore was concentrated in a zone 12 to 15 feet below the surface (Chapin, 1914 [B 592-J, p. 321-355]). Hill (1933) described a quartz vein on the property as being 5 to 6 inches wide and oriented N. 10 W., dipping 65 E. A grab sample from the dump contained $9.22 of gold per ton (0.45 ounce of gold per ton) (Hill, 1933).
Geologic map unit (-148.062433053047, 64.8905626076257)
Mineral deposit model Schist-hosted gold-quartz vein

Production and reserves

Workings or exploration The mine was developed by a 35-degree inclined shaft at least 30 feet deep; the richest ore was concentrated in a zone 12 to 15 feet below the surface (Chapin, 1914 [B 592-J, p. 321-355]).
Indication of production Yes; small

References