Location: The Gray Lead mine is situated on a ridge extending northwest from Black Mountain, just south of the headwaters of King Creek, a tributary of Tibbs Creek (BD040). The mine is located at NE1/4NW1/4 section 6, T. 7 S., R. 18 E., of the Fairbanks Meridian, approximately 54 miles northeast of Delta Junction. Winter trails up Tibbs Creek and the South Fork of the Goodpaster River provide access up Divide Creek to the top of Black Mountain. There are numerous surface workings at and surrounding the site. The Gray Lead mine is not labeled on current U.S.G.S. maps. It is locality 3 of Cobb and Eberlein (1980) who summarized relevant references under the name 'Gray Lead'.
Geology: The area is characterized by rounded hills and flat-topped ridges (Thomas, 1970). The most prominent ridge is Black Mountain, which trends about 12 miles in a northerly direction and is underlain by a Cretaceous granodiorite (Weber and others, 1978). Several creeks flow westward off Black Mountain in steep, parallel, v-shaped valleys to form the Headwaters of Tibbs Creek. Bordering Black Mountain to the west is a combination of augen gneiss, gneissic schist, and schist. There is intense shearing and faulting in the contact between the metamorphic and intrusive rocks. This shearing is observed in the underground workings and at the surface as pronounced saddle-like depressions across the spurs separating the westward-flowing tributaries of Tibbs Creek. This shear zone trends roughly N15E and dips 65 degrees NW. The lode deposits in the area are gold-bearing quartz veins in the shear zone. Most of the veins are in the shear zone, although some are found in intrusive rocks. The veins contain gold and a variable combination of sulfides, including arsenopyrite, covellite, digenite, jamesonite, pyrite, and stibnite. Typically, gold content decreases as sulfides increase. Veins are commonly 2 to 3 feet in width, with some as wide as 8 feet (Thomas, 1970). When gold is present, it is usually extremely fine grained. However, several nearby veins such as the Blue Lead mine (BD003) and Grizzly Bear mine (BD018) contain relatively coarse gold, which is easily visible in hand specimen. The Gray Lead mine is centered on a quartz vein 2 feet in width. Based on underground workings, the vein dips steeply to the west (Joesting, 1938). Foster and others (1978) performed two emission spectroscopy analyses on rock samples from the Gray Lead mine: sample 74WR-181c contained greater than 10,000ppm As, 15 ppm Ba, 150 ppm Bi, 5 ppm Co, 1 ppm Cr, 7 ppm Cu, 50 ppm Pb, 500 ppm Se, and 4.0 ppm Au; and sample 74WR-181d contained 10,000ppm As, 30 ppm B, 300 ppm Ba, 10 ppm Bi, 2 ppm Cr, 50 ppm Cu, 50 ppm La, 5 ppm Nb, 7 ppm Pb, 7 ppm Sc, 20 ppm Sn, 7 ppm Sr, 30 ppm V, 15 ppm Y, 70 ppm Zr, and 1.5 ppm Au. The Goodpaster region was first explored for placer gold in 1915. In the early 1930's, gold-bearing quartz veins were discovered in the upper Tibbs Creek area. By the winter of 1936, the first underground workings were being installed. The original base camp was on Summit Creek. A 450 foot tunnel was driven along a small vein, termed the Blue Lead Extension. After disappointing results, the work was stopped. In the summer of 1936, five men drove a 300-foot tunnel at the outcrop of the Blue Lead vein (Reed, 1937). During the winter of 1937, a 300-foot tunnel was driven at the Grizzly Bear mine (BD018) and a 50-ton mill was constructed. In the summer of 1938, the mill was moved to the Blue Lead mine and operated for a year and a half until the fall of 1939 (Joesting, 1938). Subsequently, from 1939 to 1941, approximately 1,300 feet of surface and subsurface workings were completed at the Gray Lead mine (Thomas, 1970). Over 300 feet of the vein was traced at the surface(Joesting, 1938). There was limited exploration reported in the 1970's. The mine shaft opening was accessible, but blocked by ice (Thomas, 1970). It is reported that 350 tons of ore was produced from the nearby Grizzly Bear mine and processed at the mill at the Blue Lead mine. Another 150 tons was produced from the Blue Lead mine (Reed, 1937). Thomas (1970) reports that no ore from the Gray Lead mine was taken to the mill. It is unknown how much, if any, ore was processed elsewhere.
Workings: The Goodpaster region was first explored for placer gold in 1915. In the early 1930's, gold-bearing quartz veins were discovered in the upper Tibbs Creek area. By the winter of 1936, the first underground workings were being installed. The original base camp was on Summit Creek. A 450-foot tunnel was driven along a small vein, termed the Blue Lead Extension (BD003). After disappointing results, the work stopped. In the summer of 1936, five men drove a 300-foot tunnel at the outcrop of the Blue Lead vein (Reed, 1937). During the winter of 1937, a 300 foot tunnel was driven at the Grizzly Bear mine along with the construction of a 50-ton amalgamation recovery mill. In the summer of 1938, the mill was moved to the Blue Lead mine and operated for 1.5 years until the fall of 1939 (Joesting, 1938). Subsequently, from 1939 to 1941, approximately 1,300 feet of surface and subsurface workings were completed at the Grey Lead mine (Thomas, 1970). Over 300 feet of the surface expression of the vein was traced (Joesting, 1938). There has been limited exploration reported in the 1970's. The mine shaft opening is accessible, but blocked by ice (Thomas, 1970).
Age: Postdates Cretaceous granodiorite intrusion
Production: It is reported that 350 tons of ore was produced from the Grizzly Bear mine and processed at the mill at the Blue Lead mine. Another 150 tons was produced from the Blue Lead mine (Reed, 1937). Thomas (1970) reports that no ore from the Gray Lead mine was taken to the mill. It is unknown how much, if any, ore was processed elsewhere.

Commodities (Major) - Au; (Minor) - Ag, Cu, Pb, Sb
Development Status: Yes; small
Deposit Model: Shear hosted, magmatic-hydrothermal vein

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Mineral List

8 valid minerals.