Mizpah; Black Joe Mine, Fairbanks Mining District, Fairbanks North Star Borough, Alaska, USAi

Regional Level Types
Mizpah; Black Joe Mine	Mine
Fairbanks Mining District	Mining District
Fairbanks North Star Borough	Borough
Alaska	State
USA	Country

The Mizpah claim was staked by August Hess on October 8, 1910 (Times Publishing Company, 1912). By 1912, additional partners in the claim included R.J. Geis and Charles L. Thompson.
Location: Cobb (1972, MF-413), loc. 48; SW1/4 sec. 22, T. 3 N., R. 2 E., of the Fairbanks Meridian. The mine is on the north side of Fairbanks Creek, one-half to one mile west of Too Much Gold Creek, at an elevation of 1,800 feet.
Geology: The Mizpah shear zone in the main shaft trends east-west and dips 75 S (Smith, 1913; B 525). The shaft exposed a high-grade, quartz-rich shoot which averages 2 feet in width. The Mizpah shear was traced to the northwest where the Black Joe claim was staked and a 12 foot prospect pit showed that the high grade portion of the shear was 2.5 feet thick (Times Publishing Company, 1912). The Mizpah shear contains gold and minor sulfides in a highly sheared quartz stockwork zone on the 80-foot level; strike-slip motion was noted. The gold-bearing quartz-rich zones mined to 1918 varied from 3 inches to 3 feet in width and averaged 1 foot wide. The gold-bearing shoots clearly cross-cut earlier, barren bull-quartz bodies (Mertie, 1918). Antimony-gold-lead-silver ore in an earthy manganese wad was encountered at the 60 foot station of the east drift on the 80-foot level (Mertie, 1918). Stibnite was encountered at the 80-foot station on the west drift of the 80-foot level. Stibnite in the Mizpah mine contained extremely high gold values up to $2,000 per ton (96.7 ounces of gold per ton). The average grade of ore mined through 1916 was $30 to $40 per ton in gold (1.4 to 1.9 ounces of gold per ton). In addition to gold, antimony, lead and silver, tungsten in the form of scheelite was identified on the Mizpah and Black Joe claims (Capps, 1924). Quartzite comprises the country rock in the Black Joe shaft; it strikes N 20 W and dips 18 SW. The shear zone being mined ranged in dip from 45 to 85 S. Gold values were higher and tungsten values lower on the 60-foot level, while gold values are lower and tungsten values higher between the 60- and 80-foot levels (Mertie, 1918, p. 421). By 1922, the Mizpah shaft was 220 feet deep (Davis, 1922; Stewart, 1922). Working drifts had been opened on the 80, 160 and 220 levels. Working drifts on the 80 foot level extended for 100 feet to the east and west from the shaft. Working drifts on the 160- and 220-foot levels extended for 100 feet to the east and 175 feet to the west from the shaft. The east drift on the 200-foot level was connected to the Gilmore adit via a 350-foot drift driven from the 1,000-foot station of the Gilmore adit. Davis (1922) also reported a second shaft had been sunk on a parallel shear zone 150 feet from the Mizpah shear. This shear contains 20% stibnite with minor gold and was being explored from a 120-foot deep shaft. Production through 1922 was estimated at 1,500 tons grading $25 per ton (1.2 ounces of gold per ton) (Davis, 1922). Hill (1933), sampled fractured schist, with little or no quartz, at the face of the western drift; it contained $2.30 per ton in gold (0.11 ounces of gold per ton) over a width of 16 inches. The Mizpah mine was examined as a possible antimony and/or tungsten producer in 1942 however, the mine was not found to contain either element in amounts which justified exploration or development (Killeen and Mertie, 1951; Byers, 1957). In late 1991, Dave Ebberhardt conducted limited dozer trenching on the Mizpah shear zone and exposed black-brown manganese wad on the main shear zone (R. Vetter, oral commun., 1991). The Black Joe claim remained inactive.
Workings: By late 1912, the Mizpah shaft had been sunk to a depth 120 feet with 50 feet of drifts on the 80- and 100-foot levels. The prospect remained idle until late in 1914 when development work was renewed (Eakin, 1915). By 1915, the mine was in production and was treating its ore at the nearby Heilig mill on Fairbanks Creek. A new headframe and steam hoist were installed to facilitate additional development (Stewart, 1915; Brooks, 1916, B 642; Smith, 1917, BMB 142). Mertie (1918) reported a shaft driven to a depth of 90 feet on the Black Joe claim and development drifts on the 60- and 80-foot levels. The Mizpah shaft had been extended to 160 feet deep in 1917 and the western drift on the 80-foot level had been stoped to the surface over a distance of 170 feet (Chapin, 1919). The mine was equipped with a Huntington mill situated on Fairbanks Creek below the mine. The Gilmore adit, collared at the Mizpah mill site, was 800 feet long in 1917 and nearing intersection with the Mizpah mine workings (see Gilmore prospect). By 1918, the Mizpah mine shaft was 200 feet deep and production was continuing (Martin, 1920). By 1922, the Mizpah prospect was owned by Charles Thompson and associates and the shaft was 220 feet deep (Davis, 1922; Stewart, 1922). Working drifts had been opened on the 80-, 160- and 220-foot levels. Working drifts on the 80-foot level extended for 100 feet to the east and west from the shaft. Working drifts on the 160- and 220-foot levels extended for 100 feet to the east and 175 feet to the west from the shaft. The east drift on the 200-foot level was connected to the Gilmore adit via a 350 foot drift driven from the 1,000-foot station of the Gilmore adit. Davis (1922) also reported a second shaft had been sunk on a parallel shear zone 150 feet from the Mizpah shear. In 1923, the only activity recorded at the Mizpah mine involved timber repair in the Gilmore adit (Stewart, 1923). When visited in 1931, Hill (1933) reported the shaft caved at the 130-foot level. The drift on the 80-foot level was open for 120 feet to the face, but the east drift on the 80-foot level was caved 50 feet from the shaft. In late 1991, Dave Ebberhardt conducted limited dozer trenching on the Mizpah shear zone.
Production: In late 1911 six tons of high grade ore from the main shaft had an average grade of $100 per ton in gold (4.8 ounces of gold per ton). A three-ton lot of ore from the Mizpah shear was milled in 1912 and returned average values of $92 per ton in gold or 4.4 ounces of gold per ton (Smith, 1913; B 525). Development work continued on the Mizpah prospect in 1913 but no production was recorded (Chapin, 1914). The prospect remained idle until late in 1914 when development work was renewed (Eakin, 1915). By 1915, the mine was in production and was treating its ore at the nearby Heilig mill on Fairbanks Creek. In 1916, the Mizpah mine was in production for several months and produced 200 tons of ore (Mertie, 1918). Production through 1922 was estimated at 1,500 tons grading $25 in gold per ton (1.2 ounces of gold per ton) (Davis, 1922).

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

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