Standard Copper Mines Co.

Mine, 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 60.862
Longitude -146.577
Nearby scientific data Find additional scientific data near this location
Location and accuracy This mine is at an elevation of about 1800 feet, about 0.5 mile southeast of Copper Mountain. It is in the NW1/4 sec. 1, T. 12 S., R. 8 W., of the Copper River Meridian. The location of the site is accurate to within 1000 ft. This site is loc. 13 in Cobb (1972: MF-392) and loc. C-77 in Jansons and others (1984).

Geologic setting

Geologic description

The country rocks at this mine are mafic volcanic rocks and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). The deposit consists of quartz, calcite, and massive sulfides in shear zones cutting the volcanic rocks. A 6 ft. x 32 ft. lens of massive sulfide was observed by Mihelich and Wells (1957), but most of the sulfide bodies are smaller (Jansons and others, 1984). The sulfide minerals are chalcopyrite, pyrite, pyrrhotite, and sphalerite.
Chip samples collected in 1955 (Mihelich and Wells, 1957) contained 0.07 percent to 6.1 percent Cu. Jansons and others (1984) report that three chip samples from the 660-ft.-long adit contained 280 ppm to 0.89 percent Cu, 200 ppm to 0.9 percent Zn, 0.01 parts per million (ppm) to 0.11 ppm Au, and 0.5 ppm to 2.5 ppm Ag. Three grab samples from the adit contained 0.70 percent to 2 percent Cu, 200 ppm to 2 percent Zn, 0.08 ppm to 0.19 ppm Au, and 2.3 ppm to 6.1 ppm Ag.
A 2014 grab sample contained 0.175 ppm Au, 5.35 ppm Ag,1.145 percent Cu, and 4.43 percent Zn. A stream sediment sample from below the historical workings contained 0.008 ppm Au, 0.24 ppm Ag, 729 ppm Cu, and 160 ppm Zn (Angel, 2014).
Geologic map unit (-146.578999846075, 60.8614529538574)
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
Grant and Higgins (1909) report five adits on the steep slopes of Copper Mountain and a tram to an ore bunker on the shore of Landlocked Bay. Only three of the adits could be located in the 1980s (Jansons and others, 1984). Chip samples collected in 1955 (Mihelich and Wells,1957) contained 0.07 percent to 6.1 percent Cu. Jansons and others (1984) report that three chip samples from the 660-ft.-long adit contained 280 ppm to 0.89 percent Cu, 200 ppm to 0.9 percent Zn, 0.01 parts per million (ppm) to 0.11 ppm Au, and 0.5 ppm to 2.5 ppm Ag. Three grab samples from the adit contained 0.70 percent to 2 percent Cu, 200 ppm to 2 percent Zn, 0.08 ppm to 0.19 ppm Au, and 2.3 ppm to 6.1 ppm Ag.
Field work including sampling was performed in 2014. A 2014 grab sample contained 0.175 ppm Au, 5.35 ppm Ag,1.145 percent Cu, and 4.43 percent Zn. A stream sediment sample from below the historical workings contained 0.008 ppm Au, 0.24 ppm Ag, 729 ppm Cu, and 160 ppm Zn (Angel, 2014).
Indication of production Yes
Reserve estimates Inferred reserves of 4,300 tons at 2.89 percent Cu (Jansons and others, 1984).
Production notes 32,000 lbs. Cu, 518 oz. Ag, and 36 oz. Au were recovered from 1,100 tons of ore. However, it is felt that not all the recovered gold and silver were reported (Mihelich and Wells, 1957).

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 10307357

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 9/8/2014