Eva

Prospect, Active

Alternative names

Eva Creek
Ruby Silver

Commodities and mineralogy

Main commodities Ag; Cu; Pb; Zn
Other commodities Au; Sb
Ore minerals argentiferous galena; azurite; cerussite; hematite; magnetite; malachite; pyrite; pyrrhotite; sphalerite
Gangue minerals calcite; epidote; quartz

Geographic location

Quadrangle map, 1:250,000-scale EA
Quadrangle map, 1:63,360-scale A-5
Latitude 64.1057
Longitude -143.198
Nearby scientific data Find additional scientific data near this location
Location and accuracy The center of the Eva prospect is at an elevation of about 3,900 feet on the ridge north of Eva Creek. The claims of the prospect extend several miles to the north and south into the Norvell Creek and Iron Creek drainages. The coordinates are the location of trenches in the central part of the Eva Creek prospect in section 23, T. 27 N., R. 11 E. The location is accurate.

Geologic setting

Geologic description

The Eva prospect is in Paleozoic gneiss, schist, quartzite, and marble, that have been intruded by the Mount Veta syenite of Jurassic age (Foster, 1976). Other Tertiary to Mesozoic monzonite and granite intrusions are about 1 mile east of the prospect, and there are felsic and mafic dikes in the area (Dashevsky and others, 1986). The syenite to the east is epidotized and contains local altered zones near the contact (Foster and Clark, 1970). Several other prospects are spatially associated with the Mount Veta intrusive complex, including East Eva (EA098), Drumstick (EA166), Oscar (EA096), Oscar West (EA097), Little Enchilada (EA103), unnamed (north of Fish Creek) (EA062), Molly Creek (EA100), Little Whiteman Creek (EA060), and Mitchell (EA101).
At the Eva prospect, pyrite and pyrrhotite are disseminated grains in gneiss and schist. There are also scattered highly mineralized marble units that contained argentiferous galena, cerussite, sphalerite, azurite, and malachite filling vugs, boxworks, and quartz veinlets (Carter, 1981). Wedow and others (1954) reported quartz veins as much as several feet thick, most of which are highly fractured and stained with hematite. These veins contain pods of galena, partly altered to cerussite, and calcite. Rock samples from the Eva Creek prospect with galena, sphalerite, and malachite contained as much as 9.24 ounces of silver per ton, 29.13 percent lead, and 0.61 percent copper (Saunders, 1962). Mineralized rock samples from trenches contained 0.4 to 2 percent copper, 7 to 52 percent lead, 0.6 to 21 percent zinc, and 31 to 99 ounces of silver per ton. Other samples of vein material and gossan in trenches contain as much as 32.4 ounces of silver per ton, 0.18 percent copper, 896 parts per million antimony, 9.5 percent zinc, and 6.6 percent lead (U.S. Bureau of Mines, 1995). Samples from a vein that can be traced on the surface for at least 1,800 feet contains as much as 28.7 percent lead, 9.4 percent zinc, 0.28 percent copper, 0.003 ounce of gold per ton, and 19.4 ounces of silver per ton (Swainbank and others, 1998).
Metal anomalies in soils at the Eva prospect are elongated northeast (Dashevsky and others, 1986). CEM and VLF-EM geophysical surveys both detected narrow conductors up to 400 feet long striking north to northwest. Seven hundred feet northwest of the trenches at the Eva Creek prospect, soils have elevated copper in an area of strong response to IP and ground magnetic surveys. A drill hole penetrated pyrite- and magnetite-bearing, biotite schist, and calcite-filled breccia zones as much as 58 feet thick. At the head of Iron Creek, two core holes totaling 404 feet were drilled in an area with anomalous magnetite and zinc; these holes intersected disseminated pyrite and chalcopyrite, iron oxides, and rare galena in banded marble and dolomite (Dashevsky and others, 1986).
About 18 miles of traverses were conducted for radioactive minerals in the area in 1949 but no significant radioactivity was detected in panned heavy-mineral concentrates (Wedow and others, 1954). Saunders (1962) examined prospects in the My Creek and Eva Creek area in 1960. Rock and stream-sediment samples were collected from the Molly Creek drainage in 1968 (Foster and Clark, 1970). Apex Exploration Ltd. conducted exploration in the Eva Creek area in the early 1970s (Dashevsky and others, 1986). Placid Oil Company explored in the area from 1975 to 1978; their work included float mapping, soil sampling on a grid, and ground magnetic, CEM, and VLF-EM geophysical surveys. They drilled three core holes in trenches at Eva Creek in 1977, and two core holes on Iron Creek in 1978. In 1981, Arctic Resources Inc., sampled rocks and soils at the Eva Creek prospect, and in 1982, Doyon Ltd. in 1982 ran two lines of IP-resistivity and magnetometer surveys.
Full Metal Minerals resumed exploration at the Eva prospect in 2007 and at an extension about 2,200 meters north called the Drumstick prospect (EA166) (Full Metal Minerals, 2008 [40 Mile district]; 2008 [LWM prospect]; 2008 [LWC drill sites]. They interpret the deposit as a carbonate replacement that consists of partially oxidized, massive, coarsely-crystalline sphalerite, with galena, and chalcopyrite. They collected 14 samples from outcrop and prospect pits. The samples contained 6.5 to 43.6 percent zinc, 4.1 to more than 25 percent lead, and 0.18 to 4.9 percent copper. The lowest silver value was 207 grams of silver per tonne; the highest three samples contained 3,730, 1,960, and 1,280 grams of silver per tonne.
Stevens (2010) shows several trenches spread along about 100 meters of marble, quartz-mica schist, amphibole schist, and gossan. Five holes were drilled in 2010 that totaled 632 meters. The best intercept was 1.1 meter that contained 70 grams of silver per tonne, 0.03 percent copper, 2.35 percent lead, and 1.43 percent zinc; four of the holes did not cut significant mineralization.
Geologic map unit (-143.200287765307, 64.1053507963564)
Mineral deposit model Silver-copper-lead-zinc replacement deposits in carbonate rocks (Cox and Singer, 1986; model 19a).
Mineral deposit model number 19a
Age of mineralization Jurassic or younger if related to the nearby Mt. Veta syenite.
Alteration of deposit Not noted.

Production and reserves

Workings or exploration About 18 miles of traverses were conducted for radioactive minerals in 1949 but no significant radioactivity was detected in panned heavy-mineral concentrates (Wedow and others, 1954). Saunders (1962) examined prospects in the My Creek and Eva Creek area in 1960. Rock and stream-sediment samples were collected from the Molly Creek drainage in 1968 (Foster and Clark, 1970). Apex Exploration, Ltd. conducted exploration in the Eva Creek area in the early 1970s (Dashevsky and others, 1986). Placid Oil Company explored in the area from 1975 to 1978; their work included float mapping, soil sampling on a grid, and ground magnetic, CEM, and VLF-EM geophysical surveys. They drilled three core holes in trenches at Eva Creek in 1977 and two core holes on Iron Creek in 1978. In 1981, Arctic Resources Inc. sampled rocks and soils and in 1982 Doyon Ltd. ran two lines of IP-resistivity and magnetometer surveys. Full Metal Minerals resumed exploration at the Eva prospect in 2007 and at an extension about 2,200 meters north called the Drumstick prospect (EA166) (Full Metal Minerals, 2008 [40 Mile district]; 2008 [LWM prospect]; 2008 [LWC drill sites]). Full Metal drilled 4 holes in 2010.
Indication of production None
Reserve estimates None.
Production notes None.

Additional comments

The Eva prospect is on Doyon, Ltd. selected or conveyed land. For more information contact Doyon, Ltd., Fairbanks, Alaska.

References

MRDS Number A015114

References

Carter, C.H., 1981, Doyon exploration program, Blocks 4, 5, 8, and 22: Doyon, Ltd. Report 81-27. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Dashevsky, S.S., 1983, Doyon exploration program, Block 8 - Fortymile, 1982: Doyon, Ltd. Report 83-01. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Dashevsky, S.S., 1984, Block 8 - Fortymile, summary of exploration activity of Placid Oil Company (1975-1978): Doyon, Ltd. Report 83-16. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Dashevsky, S.S., Nicol, D.L., and Bond, J., 1986, Mines, prospects, and geochemical anomalies on Doyon Limited regional overselection lands, Alaska, Blocks 1-8: Doyon, Ltd. Report 86-01a, 300 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Full Metal Minerals, 2008, 40 Mile district: http://www.fullmetalminerals.com/s/40mile.asp (as of March 4, 2008)
Full Metal Minerals, 2008, (Map showing LWC drill sites): http://www.fullmetalminerals.com/in/misc/LWM-drill.gif (as of March 4, 2008)
Full Metals Minerals, 2008, Full Metal reports high grade assay results from LWM prospect: /www.fullmetalminerals.com/s/NewsReleases.asp?ReportID=283603&_Type=News&_Title=Full-Metal-Reports-High-Grade-Assay-Results-from-LWM-Prospect-40-Mile-Prope... ( News Release, Jan 29, 2008)
Stevens, D.L., 2010, 40-Mile project, Fortymile Mining District, East-Central Alaska: Unpublished NI 43-101 report for Full Metal Zinc Ltd. and Full Metal Minerals Ltd., 177 p. (posted on www.sedar.com, April 21, 2011).
Sweet, K., 1982, Interpretation report of the geophysical surveys conducted on Block 8 and Block 20: Doyon, Ltd. Report 82-36. (Report held by Doyon, Ltd., Fairbanks, Alaska).
WGM Inc., 1998, Veta property, 1997 annual report, volume 1: Doyon, Ltd. Report 98-10, 227 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).
Reporters R.L. Flynn and M.B. Werdon (ADGGS); D.J. Grybeck (Contractor, USGS)
Last report date 4/1/2012