Willis

Mine, Inactive

Alternative names

Willis and Fuller

Commodities and mineralogy

Main commodities Hg
Other commodities Sb
Ore minerals cinnabar; pyrite; stibiconite; stibnite
Gangue minerals hematite; quartz

Geographic location

Quadrangle map, 1:250,000-scale SM
Quadrangle map, 1:63,360-scale D-4
Latitude 61.81575
Longitude -157.36375
Nearby scientific data Find additional scientific data near this location
Location and accuracy The Willis Mine is on a knob east of the east branch of Willis Creek, about 1.4 mile northwest of the mouth of Parks Creek. It is at an elevation of about 700 feet in the NW1/4 sec. 24, T. 20 N., R. 45 W., of the Seward Meridian. The mine is locality 9 of Miller and others (1989). The location is accurate.

Geologic setting

Geologic description

The Willis deposit is in sandstone, siltstone, and shale of the Upper Cretaceous,s Kuskokwim Group and in altered mafic dikes (Cady and others, 1955; Sainsbury and MacKevett, 1965). The deposit consists of quartz veins that contain cinnabar, stibnite, pyrite, hematite, and minor stibiconite. The veins are up to 50 feet long and 6 inches thick; they fill fractures in or near mafic dikes and sills that are largely altered to silica, carbonate minerals, and dickite. The veins strike N30-65W and dip steeply either NE or SW (Sainsbury and MacKevett, 1965). The cinnabar grains, which are zoned, are brilliant red or dark purple and iron-enriched (Sainsbury and MacKevett, 1965).
The ore bodies are localized near the intersections of altered gently-dipping dikes and sills with bedding plane faults that cut the Kuskokwim Group. The quartz-cinnabar-stibnite veins appear to parallel the strike of the shallow- dipping dikes and sills, a structural setting that differs somewhat from that at the Red Devil Mine (SM028). The mineralization is in a broad northwest-trending zone parallel to the axis of the Sleetmute anticline (Cady and others, 1955).
The property was first staked in 1909 by Oswald Willis and Jack Fuller, who retorted a few flasks of mercury from 1914 to 1918 (Cady and others, 1955).
Geologic map unit (-157.366131454006, 61.815060090206)
Mineral deposit model Silica-carbonate mercury (Cox and Singer, 1986; model 27c).
Mineral deposit model number 27c
Age of mineralization Undated; the nearby Fairview prospect (ARDF SM019) has a 40Ar/39Ar age of 72.6 Ma (Gray, Gent, and others, 1997).
Alteration of deposit Mafic dikes and sills are are largely altered to silica, carbonate minerals, and dickite.

Production and reserves

Workings or exploration The property was staked by Oswald Willis and Jack Fuller; in 1943, it was conveyed to Oswald's nephew George Willis. The U.S. Bureau of Mines trenched the property in 1943 (Webber and others, 1947). Development work was limited to trenches, pits and several short adits into mineralized outcrops (Jasper, 1955, [PE 82-3]), 1961; Sainsbury and MacKevett, 1965; Miller and others, 1989). After George Willis trenched the property in 1953 and 1954, Jasper (1961) suggested that the Willis prospect could be a large, low grade, bulk-mineable mercury deposit. Alaska Mines and Minerals Inc. optioned the property in 1957.
Indication of production Yes; small
Production notes Oswald Willis and Jack Fuller retorted ore and produced a few flasks of mercury from 1914 to 1918 (Cady and others, 1955).

References

MRDS Number A013434

References

Gray, J.E., Gent, C.A., Snee, L.W., and Wilson, F.H., 1997, Epithermal mercury-antimony and gold-bearing vein lodes of southwest Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 287-305.
Wells, J.T., and Ghiorso, M.S., 1988, Rock alteration, mercury transport, and metal deposition at Sulphur Bank, California: Economic Geology, vol. 83, p. 606-618.
White, D. E., and Robinson, C. E., 1962, Sulphur Bank, California, a major hot spring quicksilver deposit, in Engel, A.E.J., James, H.L., and Leonard, B.F., eds., Petrologic studies: A volume in honor of A.F. Buddington: Boulder, Colorado, Geological Society of America p. 397-428.
Reporters T.K. Bundtzen (Pacific Rim Geological Consulting, Inc.) and M.L. Miller (U.S. Geological Survey)
Last report date 5/3/2003