Willis; Willis and Fuller Mine, Aniak Mining District, Bethel Census Area, Alaska, USAi

Regional Level Types
Willis; Willis and Fuller Mine	Mine
Aniak Mining District	Mining District
Bethel Census Area	Census Area
Alaska	State
USA	Country

Location: 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.
Geology: 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).
Workings: 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.
Age: Undated; the nearby Fairview prospect (ARDF SM019) has a 40Ar/39Ar age of 72.6 Ma (Gray, Gent, and others, 1997).
Alteration: Mafic dikes and sills are are largely altered to silica, carbonate minerals, and dickite.
Production: Oswald Willis and Jack Fuller retorted ore and produced a few flasks of mercury from 1914 to 1918 (Cady and others, 1955).

Commodities (Major) - Hg; (Minor) - Sb
Development Status: Yes: small
Deposit Model: Silica-carbonate mercury (Cox and Singer, 1986; model 27c).

Other Databases

Link to USGS - Alaska:	SM020

Other Regions, Features and Areas containing this locality

References