Seattle Alaska Copper Co.

Mine, Inactive

Commodities and mineralogy

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

Geographic location

Quadrangle map, 1:250,000-scale BS
Quadrangle map, 1:63,360-scale D-3
Latitude 59.965
Longitude -147.989
Nearby scientific data Find additional scientific data near this location
Location and accuracy The occurrence consists of three tunnels that are located just below VABM Fairview 1926; it is in the NE1/4 of section 36, T. 2 S., R. 8 E., of the Seward Meridian. The lower tunnel is at an elevation of 1,150 feet. The middle tunnel is at an elevation of 1,350 feet and the upper tunnel is at an elevation of 1,450 feet. There is an open cut on the discovery outcrop just above the upper tunnel. This is location number 8 of Cobb (1972, MF-440) and location 270 of Tysdal (1978). This location is accurate to within a quarter of a mile.

Geologic setting

Geologic description

The country rock in the vicinity of the prospect is graywacke and shale of the Tertiary Orca Group (Nelson and others, 1980). The strike of the bedding is northeast and dips 70 W. The mineralization consists of siliceous massive sulfides and stringers of sulfides containing predominantly pyrite, pyrrhotite, and chalcopyrite. The mineralization varies from 18 to 66 inches in width and strikes N 35 to 50 E and dips 70 to 80 W. Locally the mineralization is parallel to the schistosity of the country rock. Samples by the Bureau of Mines (Kurtak and Jeske, 1986) assayed up to 6.5 percent copper and 14 ppm silver.
Geologic map unit (-147.991027671304, 59.9643423007038)
Mineral deposit model Cyprus massive sulfide (Cox and Singer, 1986; model 24a).
Mineral deposit model number 24a
Age of mineralization Tertiary; massive sulfides in Tertiary rocks.

Production and reserves

Workings or exploration There were 840 feet of underground workings driven between 1908 and 1911. In 1911 a mill was set up and run for a short while. In 1914 a test shipment of 12 tons of ore that ran 0.97 percent copper and 1.92 ounces of silver per ton resulted in the production of 2,350 pounds of copper and 23 ounces of silver (Johnson, 1918 p. 209-210). The prospect has tunnels at three levels and one open cut. The lower two tunnels are the most extensively developed. The lower tunnel is collapsed and reported to consists of 400 feet of workings. The middle tunnel was open in 1985 and is about 400 feet long; two drifts, 20 feet and 50 feet in length, were driven along the mineralized zone. The Bureau of Mines (Kurtak and Jeske, 1986) sampled the middle tunnel across a four foot width that contained 6.5 percent copper and 14 ppm silver. The 40-foot-long upper tunnel is collapsed. Martin and others (1915) reported that this tunnel was weakly mineralized. In 1976, Noranda Exploration staked the area and conducted geophysical studies.
Indication of production None
Reserve estimates Kurtak and Jeske (1986) inferred a reserve of 2,900 tons copper in ore that contains 3 percent copper and 8.7ppm silver.
Production notes In 1914 a test shipment of 12 tons of ore that ran 0.97 percent copper and 1.92 ounces of silver per ton resulted in the production of 2,350 pounds of copper and 23 ounces of silver (Johnson, 1918 p. 209-210).

References