Evelyn Lee

Prospect in Alaska, United States with commodities Silver, Gold, Copper

Geologic information

Identification information

Deposit ID 10001396
MRDS ID A012138
Record type Site
Current site name Evelyn Lee

Geographic coordinates

Geographic coordinates: -149.26334, 67.65972 (WGS84)
Relative position This site is at an elevation of about 4,400 feet on a ridge between Sheep Creek and Spruce Creek west of Horace Mountain (NW1/4 sec. 25, T. 33 N., R. 8 W., of the Fairbanks Meridian). Its location is taken from maps published on the Internet website of the current operator, Ventures Resource Corp. (URL http://www.venturesresource.com/). The known mineralized area extends approximately 1/2 mile northeast and southwest of the reference point. The location is accurate within a 1/2-mile radius.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Gold Primary
Copper Primary

Materials information

Materials Type of material
Bornite Ore
Chalcopyrite Ore
Gold Ore
Pyrite Ore

Alteration

  • (Local) Potassic and sericitic alteration in the meta-igneous rocks. Calc-silicate hornfels.

Mineral occurrence model information

Model code 58
USGS model code 18a
Deposit model name Porphyry Cu, skarn-related
Mark3 model number 9

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Hornblendite
    Stratigraphic age (youngest) Late Devonian
  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Marble
    Rock unit name Skajit Limestone
    Rock description Skajit Limestone

Nearby scientific data

(1) -149.26334, 67.65972

Comments on the geologic information

  • Geologic Description = The Evelyn Lee prospect is one of a number of Cu skarn deposits in the Chandalar area which have been described in general by Newberry and others (1986). They are all located northwest of the belt of the Devonian(?) Horace Mountain granitic rocks. Many of the Cu skarns exhibit both prograde garnet/pyroxene and retrograde epidote and actinolite mineral assemblages. Newberry and others (1986) stateed that the mineralogy, mineralization, and alteration of these skarns tend to place them in the category of continental-margin, porphyry-related copper skarns. ? Dillon and others (1996) mapped the area as Devonian Horace Mountain granite gneiss and Devonian felsic schists with proximal tactite and calcareous hornfels. The Devonian felsic schists are interpreted by Dillon and others (1996) as hypabyssal to plutonic in origin, but they are not included in the Horace Mountain plutonic assemblage. Early descriptions (early to mid-1970s) of the Evelyn Lee prospect described chalcopyrite, bornite, and pyrite in isolated skarn bodies that occur in marble in the Skajit Limestone near or at the contact with Devonian hornblende granodiorite porphyry. Skarn bodies were reported to be as much as 100 m long and 10 m wide. Copper grades as high as 10 percent Cu were obtained from outcrops. Altered and pyritized meta-granodiorite bodies are spatially associated with the mineralized skarns. ? Mineralization on the property has been described by Ventures Resource Corp. as consisting of pyrite, chalcopyrite, and bornite with silver and gold found in metamorphosed VMS, skarn, and sheared granitic-hosted deposits. Ventures Resource considers the target model for this prospect to be copper-gold skarn mineralization related to copper porphyry-type intrusives. The host rocks are volcanogenic calc-schist, chloritic calc-schist, limestone and dolomite, and intensely sheared granitic intrusive. Structurally, the host rocks form a broad syncline intruded along the keel by granodiorite. Assays include grades of 9.9 percent Cu and 8.17 ounces of silver per ton from a 7-foot-thick zone of sulfides in skarn, and a 5-foot surface sample which grades 5.6 percent Cu and 0.04 ounce of gold per ton. A core sample assayed 3.5 percent Cu over a 23.5-foot drill intercept.
  • Age = Devonian based on reported Early Devonian Pb/Pb zircon ages from the associated Baby Creek batholith and Horace Mountain plutons (Dillon and others, 1996).

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Active

Mining district

District name Koyukuk

Comments on the reserve resource information

  • Reserves = Estimates of potential for this property ranges from about 1 million metric tons of 5 percent Cu (DeYoung, 1978) to 'tens of million of tons grading 2 percent to 5 percent Cu with gold and silver credits' (Ventures Resource Corporation website, 1998, URL http://www.venturesresource.com/).

Comments on the workings information

  • Workings / Exploration = Claims were staked in 1969 and 1970. The property was selected by Doyon, Limited (an Alaska Native Corporation) in the early 1970s as part of Alaska Native Claims Settlement Act (ANCSA) settlement. In 1998 the Evelyn Lee property was being explored by Ventures Resource Corporation under the terms of an exploration agreement with the owner, Doyon, Limited. Sampling results from a large soil sample grid (approximately 5,000 feet x 2,500 feet ) shows extensive areas of more than 500 ppm Cu in soil (Ventures Resource Corporation,1998). A grade 9.9 percent Cu and 8.17 ounces of Ag per ton of was obtained from sampling of a 7-foot-thick sulfide layer in skarn. Two shallow core drill holes have explored one of the copper soil anomalies. This drilling encountered mineralization that assayed 3.5 percent copper from surface to 23.5 feet and 2 percent copper from surface to 18 feet.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A012138
USGS Alaska Resource Data File ARDF CH059

Bibliographic references

  • Deposit

    Grybeck, D.J., 1977, Known mineral deposits of the Brooks Range, Alaska: US Geological Survey Open-File Report 77-166C, 41 p., 1 sheet, scale 1:1,000,000.

  • Deposit

    DeYoung, J.H., Jr., 1978, Mineral resources map of the Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-B, 2 sheets, scale 1:250,000.

  • Deposit

    Marsh, S.P., and Wiltse, M.A., 1978, Composite geochemical map showing major alteration zones, and detailed geologic maps of selected mineral prospects, Chandalar quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-878-I, 1 sheet, scale 1:250,000.

  • Deposit

    Adams, D.D., and Dillon, J.T., 1985, Geochemical investigations in the Chandalar C-5 and C-6 quadrangles, Alaska: Alaska Division of Geological and Geophysical Surveys Public-Data File 85-26, 37 p., 3 sheets, scale 1:63,360. (Superseded by RI 88-15.)

  • Deposit

    Newberry, R.J., Dillon, J.T., and Adams, D.D., 1986, Regionally metamorphosed calc-silicate-hosted deposits of the Brooks Range, northern Alaska: Economic Geology, v. 81, p. 1728-1752

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p.

  • Deposit

    Adams, D.D., and Dillon, J.T., 1985, Geochemical investigations in the Chandalar C-5 and C-6 quadrangles, Alaska: Alaska Division of Geological and Geophysical Surveys Public-Data File 85-26, 37 p., 3 sheets, scale 1:63,360. (Superseded by RI 88-15.)

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, Donald, Robinson, M.S., Smith, T.E., and Yeend, Warren, 1988, Metallogeny and major mineral deposits of Alaska: U.S. Geological Survey Open-File Report 88-73, 97 p., 2 plates, scale 1:5,000,000.

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Grybeck, D.J., Koch, R.D., Eremin, R.A., Rozenblum, I. S., Sidorov, A.A., Byalobzhesky, S.G., Sosunov, G.M., Shpikerman, V.I., Gorodinsky, M.E., 1993, Metallogenesis of mainland Alaska and the Russian Northeast: U.S. Geological Survey Open-File Report 93-0339, 3 sheets, 230 p.

  • Deposit

    Ventures Resource Corporation, 1998, 1997 Annual Report and Website (Worldwide Web URL http://www.venturesresource.com/).

  • Deposit

    Newberry, R.J., Allegro, G.L., Cutler, S.E., Hagen-Levelle, D.D., Adams, D.D., Nicholson, L.C., Weglarz, T.B., Bakke, A.A., Clautice, K.H., Coulter, G.A., Ford, M.J., Myers, G.L., and Szumigala, D.J., 1997, Skarn deposits of Alaska, in Goldfarb, R.J., and Miller, L.D., eds., Mineral Deposits of Alaska: Economic Geology Monograph 9, p. 355-395.

  • Deposit

    Nokleberg, W.J., Bundtzen, T.K., Dawson, K.M., Eremin, R.A., Goryachev, N.A., Koch, R.D., Ratkin, V.V, Rozenblum, I.S., Shpikerman, V.I., Frolov, Y.F., Gorodinsky, M.E., Melnikov, V.D., Diggles, M.F., Ognyanov, N.V., Petrachenko, E.D., Petrochenko, R.I., Pozdeev, A.I., Ross, K.V., Wood, D.H., Grybeck, D., Khanchuck, A.I., Kovbas, L.I., Nekrasov, I.Y., and Sidorov, A.A., 1996, Significant metalliferous and selected non-metalliferous lode mineral deposits and placer districts, and for metallogenesis of the Russian Far East, Alaska, and the Canadian Cordillera: U.S. Geological Survey Open-File Report 96-513-B, 385 p.; U.S. Geological Survey Open-File Report 96-513-B, 385 p. (CD-ROM format).

  • Deposit

    Maas, K.M., 1987, Maps summarizing land availability for mineral exploration and development in northern Alaska, 1986: U.S. Bureau of Mines Open-File Report 10-87, 33 quadrangle overlays.

Comments on the references

  • Primary Reference = Ventures Resource Corporation, 1998

General comments

Subject category Comment text
Deposit Model Name = Porphyry Cu, skarn-related deposits (Cox and Singer, 1986; model 18a)
Deposit Other Comments = See also: Venus (CH065), Victor (CH064), Eva (CH063), and Geroe Creek (CH053) prospects. Alaska Kardex No. KX-31-53H (Kardex is a card file mining claim information system located at the State of Alaska DNR Public Information Center in Fairbanks).

Reporter information

Type Date Name Affiliation Comment
Reporter 17-NOV-1999 J.M. Britton U.S. Geological Survey