Chatham Mine, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Chatham Mine	Mine
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

Location: Cobb (1972, MF-413), loc. 44; NE1/4NE1/4 sec. 29, T. 3 N., R. 2 E., of the Fairbanks Meridian. This mine is at the extreme head of Chatham Creek, at an elevation of 1,825 feet, adjacent to the cabins marked on the Livengood (A-1) quadrangle map.
Geology: The prospect was located in 1908 when Fred Fey discovered a large quartz boulder with visible gold (Times Publishing Company, 1912). About 150 feet below this discovery, an adit revealed a shear zone striking N 60 W and dipping 65 to 80 S. The shear exhibits prominent slickensides showing nearly horizontal strike-slip motion (Smith, 1913; B 525). Average ore width in the stopes was 14 inches (Times Publishing Company, 1912). A stibnite-bearing shear zone striking east and dipping south cuts the Chatham shear in the southeast drift about 150 feet from the main adit (Brooks, 1914). The stibnite occurs in massive, lenticular pods oriented diagonally to the strike of the shear zone. The shear zone is 10 to 15 feet wide and was traced on the surface for over 500 feet. Individual pods range from a few inches to several feet in width and are 10 to 12 feet in length. In a raise 825 feet from the portal, the stibnite is along a N 70 E, vertically-dipping shear zone with about 18 inches of pure stibnite in a clay-rich gouge zone (Brooks, 1918). This mine produced both gold and anitmony ore. Ore from the Chatham mine was estimated to contain $30 to $40 per ton in gold (1.45 to 1.93 ounces of gold per ton) (Times Publishing Company, 1912). Workings consisted of the main 1300 foot Chatham adit and a Lower adit which was collared 120 feet below the Chatham adit. The Chatham mine area was examined by Fairbanks Exploration Inc. in 1986 and preliminary sampling conducted (Fairbanks Exploration Inc., unpublished report, 1986). A sample taken from a small pit near the head of Chatham Creek contained 1800 ppb gold, with anomalous silver, arsenic and antimony. The sample consisted of scorodite and stibiconite in stained carbonaceous quartzite with no visible sufides. Visible gold was found in the pit from which this sample was extracted.
Workings: By mid-1916, the main Chatham adit had been driven 1,300 feet (Brooks, 1918). Approximately 400 feet of the shear zone had been stoped from the drift level to the surface; the workings extended from a point 175 feet northwest of the main adit to a point 225 feet southeast of it (Brooks, 1914). A second adit was collared 120 feet below the Chatham adit.
Alteration: Scorodite and stibiconite in carbonaceous quartzite.
Production: On August 12, 1912, a 12-ton-per-day two-stamp Joshua Hendy mill began treating the Chatham mine gold ore (Times Publishing Company, 1912). Approximately 100 tons of stibnite was mined from a four-foot-thick pod in the east drift (Stewart, 1915). Total amount of gold and antimony ore production is not known.

Commodities (Major) - Au; (Minor) - Sb
Development Status: Yes; small
Deposit Model: Polymetallic vein (Cox and Singer, 1986; model 22c).

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Link to USGS - Alaska:	LG147

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References