Galena Bay Mining Co. (Vesuvius Valley)

Prospect, Inactive

Commodities and mineralogy

Main commodities Cu; Zn
Other commodities Ag; Au
Ore minerals chalcopyrite; pyrite; pyrrhotite; sphalerite
Gangue minerals calcite; quartz

Geographic location

Quadrangle map, 1:250,000-scale CV
Quadrangle map, 1:63,360-scale D-7
Latitude 60.878
Longitude -146.594
Nearby scientific data Find additional scientific data near this location
Location and accuracy This site represents several prospects in a roughly circular, half-mile-square, area at about 2000 feet elevation on the northeast face of Bells Butte. The area is in the N1/2 secs. 26 and 35, T. 11 S., R. 8 W., of the Copper River Meridian. The location is accurate to within 1000 ft. This area of prospects is shown in Cobb (1972: MF-392) as sites #9 and #10; in Jansons and others it is shown as site C-83.

Geologic setting

Geologic description

The country rocks at these prospects are mafic volcanic rocks and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). The deposit consists of shear-zone-hosted masses of calcite, quartz, chalcopyrite, pyrite, pyrrhotite, and sphalerite. Capps and Johnson (1915) reported that most of the ore was found in numerous 1- to 20-ft.-wide shear zones in pillow basalt (greenstone). The shear zone containing most of the early workings is 1000 ft. long.
Jansons and others (1984) collected chip samples that contained 58 parts per million (ppm) to 13 percent Cu, 46 ppm to 2 percent Zn, and <0.1 ppm to 32.8 ppm Ag; their grab samples contained 80 ppm to 6.1 percent Cu, 790 ppm to 20.1 percent Zn, and 1.1 ppm to 20 ppm Ag. Small amounts of gold were reported in earlier assays (Capps and Johnson, 1915).
Four grab samples were collected in 2014 at approximately 60.886 N 146.601 W. Three samples were taken from an ore stockpile below an adit, the other sample was collected above the adit, at an exploration trench. The trenching was conducted on a quartz rich epithermal breccia. Sample 1 from ore stockpile contained 0.056 ppm Au, 25.6 ppm Ag, 3.57 percent Cu, and 5.4 percent Zn. Sample 2 contained 0.178 ppm Au, 74.2 ppm Ag, 10.65 percent Cu, and 2.15 percent Zn. Sample 3 contained 0.021 ppm Au, 5.81 ppm Ag, 0.692 percent Cu, and 0.772 percent Zn. Sample 4 taken from the trench contained 0.013 ppm Au, 3.13 ppm Ag, 0.449 percent Cu and 1.36 percent Zn (Angel, 2014).
Geologic map unit (-146.596001520085, 60.8774536058619)
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 Oxidation of copper minerals (Angel, 2014).

Production and reserves

Workings or exploration
Capps and Johnson (1915) reported nine adits with a total of about 3000 ft. of underground workings, and some open cuts and buildings. The longest (2200 ft) adit was caved by the early 1980s (Jansons and others, 1984). Jansons and others (1984) collected chip samples that contained 58 parts per million (ppm) to 13 percent Cu, 46 ppm to 2 percent Zn, and <0.1 ppm to 32.8 ppm Ag; their grab samples contained 80 ppm to 6.1 percent Cu, 790 ppm to 20.1 percent Zn, and 1.1 ppm to 20 ppm Ag. Small amounts of gold were reported in earlier assays (Capps and Johnson, 1915).
Field work including sampling was performed in 2014. Four grab samples were collected in 2014 at approximately 60.886 N 146.601 W. Three samples were taken from an ore stockpile below an adit, the other sample was collected above the adit, at an exploration trench. The trenching was conducted on a quartz rich epithermal breccia. Sample 1 from ore stockpile contained 0.056 ppm Au, 25.6 ppm Ag, 3.57 percent Cu, and 5.4 percent Zn. Sample 2 contained 0.178 ppm Au, 74.2 ppm Ag, 10.65 percent Cu, and 2.15 percent Zn. Sample 3 contained 0.021 ppm Au, 5.81 ppm Ag, 0.692 percent Cu, and 0.772 percent Zn. Sample 4 taken from the trench contained 0.013 ppm Au, 3.13 ppm Ag, 0.449 percent Cu and 1.36 percent Zn (Angel, 2014).
Indication of production None
Reserve estimates Inferred reserves of 5,800 tons at 7.9 percent Cu, 1.3 percent Zn, and 5 ppm Ag (Jansons and others, 1984).
Production notes None.

Additional comments

Nelson and others (1985) interpret the country rocks as accreted ocean crust. Crowe and others (1992; 1993) and Sainsbury (1993) discuss the genesis of the volcanogenic massive sulfide deposits in this area.
Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.

References

MRDS Number 10307354

References

Angel, A.K., 2014 Mineral Assessment of Chugach Alaska Lands, Unpublished Report, 21p. (Report held by Chugach Alaska Corporation, Anchorage, Alaska).
Sainsbury, C.L., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska, A discussion: Economic Geology, v. 88, p. 1284-1285.
Reporters S.W. Nelson, Anchorage, AK; A.K. Angel (Alaska Earth Sciences, Inc.)
Last report date 9/9/2014