Slate Creek

Mine, Inactive

Alternative names

Taylor mine

Commodities and mineralogy

Main commodities Sb
Other commodities Pb
Ore minerals arsenopyrite; boulangerite; cervantite; kermesite; pyrite; stibiconite; stibnite
Gangue minerals quartz

Geographic location

Quadrangle map, 1:250,000-scale MM
Quadrangle map, 1:63,360-scale B-3
Latitude 63.4825
Longitude -151.0736
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Slate Creek antimony mine (Cobb, 1980, p. 75-76 [OFR 80-363]) is at the head of Slate Creek. It is at an elevation of about 2700 feet, about one mile south of the rounded top of Brooker Mountain. The mine is accessible by a bulldozed trail up Eldorado Creek and Slate Creeks. The mine, marked by a mine symbol on the Mt. McKinley B-3 quadrangle map, is in the SE1/4 sec. 32, T. 16 S., R. 18 W., Fairbanks Meridian. The location is acccurate within 500 feet. It is location 1 of both Cobb (1972 [MF 366]) and MacKevett and Holloway (1977).

Geologic setting

Geologic description

The Slate Creek antimony deposit is in a quartzitic unit of the Precambrian Birch Creek Schist (Bundtzen, 1981). The ore is in a shear zone that, as developed in underground workings, strikes N50E and dips steeply S. As exposed in an open pit east of the underground workings, the zone appears to turn northerly and then easterly (Thornsberry, McKee, and Salisbury, 1984). The deposit has been traced by underground and surface workings for about 650 feet. The shear zone and antimony mineralization appear to continue beyond the known limits of the deposit. Soil samples collected in 1983 define a 200-foot-wide antimony anomaly that extends 1000 feet east and 500 feet west of the workings (Thornsberry, McKee, and Salisbury, 1984, p. 144). Hawley and Associates (1978) found anomalous amounts of antimony in stream-sediment samples about 1/2 mile west-southwest of the mine.
The deposit is a reticulated quartz stockwork in the shear zone. As developed before 1918, the deposit is up to about 15 feet wide, strikes N50E and dips 82S (Capps, 1919, p. 107-108). Subsequent work showed that the shear zone is locally about 40 feet thick, and that the ore zones locally are more than 20 feet thick (Ebbley and Wright, 1948). The deposit appears to thin with depth; an operator in 1983 reported that it is about 1 foot wide at the base of the pit (Thornsberry, McKee, and Salisbury, 1984).
Quartz is the chief gangue mineral. Pyrite occurs locally, but is not closely associated with the ore. Arsenopyrite and the lead-antimony sulfide boulangerite occur locally in the ore. As exposed in surface cuts, stibnite grades into its oxidation products stibiconite, kermesite, and cervantite. The presence of kermesite in particular appears to indicate a nearby pod of high-grade ore. The deposit is probably early to mid-Tertiary; mineralization at the nearby Bonnell prospect (MM030) postdates a lower Tertiary quartz porphyry pluton. The Slate Creek deposit has long been recognized as one of the main antimony deposits in the Kantishna district (Berg and Cobb, 1967, p. 229-231).
Geologic map unit (-151.075882242644, 63.4819892496449)
Mineral deposit model Simple stibnite deposit (Cox and Singer, 1986; model 27d).
Mineral deposit model number 27d
Age of mineralization The deposit is probably early to mid-Tertiary; mineralization at the nearby Bonnell prospect (MM030) postdates a lower Tertiary quartz porphyry pluton.
Alteration of deposit Locally significant oxidation of antimony minerals.

Production and reserves

Workings or exploration
The Slate Creek antimony deposit was discovered in 1905 and staked in 1907. It was reported to Brooks (1916) in 1914 or 1915, but was first visited by the U.S. Geological Survey in 1916 (Capps, 1918, 1919). Capps described a 97-foot-long drift adit with 22 feet of crosscuts and a cut above the underground workings. At that time there was about 125 tons of hand-sorted stibnite stockpiled at the mine. None had been shipped. The mine appears to have closed at the end of World War I and to have been inactive in the 1920s. Wells, who studied the area in 1931, reported that the workings were caved (Wells, 1933, p. 376-377).
Mining resumed during World War II, and some ore was shipped in 1942 (Joesting, 1942). The prospect was examined in July 1942 by the U.S. Bureau of Mines, who suggested that limited exploration could add to the mine reserves. A bulldozer trenching program in August, 1942, dug 5 trenches over an approximate strike length of 400 feet along the northeast trend of the deposit. Two of the trenches cut commercial ore. The ore body intersected in trench 2 was about 26 feet wide and contained an estimated 18.7 percent antimony. The trenching was followed by churn drilling (Ebbley and Wright, 1948, p. 23). Further exploration work was done in 1943 and 1944. The reserve developed by Bureau of Mines drilling and trenching totaled about 10,000 tons grading 9.4 percent antimony, and 6,700 tons of partly developed ore containing about 10 percent antimony (Bain, 1946, p. 67). The mine remained active from 1942 until 1949; it operated again in 1971-72 (Bundtzen, Smith, and Tosdal, 1976) and in the early 1980s (Thornsberry, McKee, and Salisbury, 1984). No significant work has been done at the mine since about 1985.
Indication of production Yes
Production notes
The Slate Creek or Taylor antimony mine has produced a total of about 679 tons of hand-picked antimony ore. Production from the time the mine opened before 1916 to the end of World War II totaled about 325 tons of ore averaging 49 percent antimony. From World War II to 1983, the mine produced about 354 tons of ore that averaged 60 percent antimony.
About 22 tons of antimony ore were produced in 1983 (Thornsberry, McKee, and Salisbury, 1984).

Additional comments

The mine is in Denali National Park and Preserve.

References

MRDS Number A011251

References

Bundtzen, T.K., 1981, Geology and mineral deposits of the Kantishna Hills, Mt. McKinley quadrangle, Alaska: M. S. Thesis, University of Alaska, College, Alaska, 238 p.
Reporters C.C. Hawley
Last report date 12/18/2000