McLeod

The McLeod is a molybdenum mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: McLeod

Commodity

Primary: Molybdenum
Secondary: Uranium
Secondary: Tungsten
Secondary: Manganese
Secondary: Tin
Secondary: Copper
Secondary: Lead
Secondary: Silver

Location

State: Alaska
District: Kaiyuh

Land Status

Not available

Holdings

Type: Located Claim

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Prospect
Operation Type: Unknown
Years of Production:
Organization:
Significant: Y

Physiography

Not available

Mineral Deposit Model

Model Name: Porphyry Mo, low-F

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: The intrusive rocks are locally silicified and sericitized (Mertie, 1937). The adjacent country rocks are marked by extensive hornfelsing, secondary pyrite, and chloritic alteration.

Rocks

Role: Host
Age Type: Host Rock
Age Old: Early Cretaceous

Analytical Data

Not available

Materials

Ore: Ferrimolybdite
Ore: Molybdenite
Gangue: Magnetite
Gangue: Pyrrhotite
Gangue: Quartz
Gangue: Tourmaline
Gangue: Quartz
Gangue: Pyrite

Comments

Comment (Geology): Age = Late Cretaceous or Tertiary, the age of the granitic stock and its apophyses.

Comment (Geology): Age = Cretaceous or Tertiary, the presumed age of the mineralized felsic intrusive hostrock.

Comment (Geology): Age = Host rock is Tertiary - Cretaceous.

Comment (Deposit): Model Number = 16a, 21b

Comment (Deposit): Other Comments = This property is on Doyon, Ltd. selected lands. For more information contact Doyon, Ltd., in Fairbanks, Alaska.

Comment (Geology): Geologic Description = This deposit consists of platy aggregates and grains of molybdenite in sparse, northeast-trending, milky-white quartz veinlets and veins up to 8 inches thick (Mertie, 1937). The veins cut hornfels, clastic sedimentary rocks, minor intermediate to mafic volcanic rocks, and biotite-quartz-feldspar porphyritic dikes, near the southwestern margin of a Cretaceous or Tertiary quartz-feldspar-porphyritic granite stock. The stock is exposed in a 3/4-square-mile area, but the extent of the hornfels suggests that the pluton is considerably larger at depth (Bressler and others, 1979). The dikes postdate the stock and generally strike northeast. The general strike of the strata is northwesterly with gentle dips to the northeast and southwest. There is very little outcrop, but vein float trending about N60E can be traced in frost-riven rubble for several hundred feet on the ridge and downslope (West, 1954).? the deposit also contains pyrite, pyrrhotite, molybdenite altered to ferrimolybdenite, magnetite, zircon, and tourmaline (West, 1954). Selected samples of molybdenite- and ferrimolybdenite-bearing quartz vein material assay 0.23 to 1.49% Mo. A sample submitted in 1942 by McLeod (probably from this prospect) contained approximately 4% molybdenite (Joesting, 1943). Early indications of elevated uranium content were not substantiated by sampling by the U.S. Geological Survey (West, 1954, p. 9-10). No sample contained more than 0.0003% eU.? the mineralized veins are mainly in highly fractured, silicified pyritic hornfels adjacent to biotite-quartz -porphyritic dikes. Mineralized veinlets in the dikes are rare. A multi-element and molybdenum soil anomaly that marks the deposit measures 3500 by 2700 feet (Bressler and others, 1979). The anomaly partly coincides with mapped alteration and with exposures of molybdenite-bearing quartz veinlets; the anomaly is open to the southwest (Bressler and others, 1979).? Also see UL004 and 005.

Comment (Commodity): Gangue = Pyrrhotite

Comment (Workings): Workings / Exploration = Several prospect pits and trenches were dug and caved prior to 1945 (West, 1954). There has been no underground exploration at this site. Surface exploration and mapping was conducted by Bear Creek Mining Company in 1976 (Fields, 1976), and by WGM, Inc., on behalf of Doyon, Ltd., in 1979 and 1980 (Bressler and others, 1979; Lessman, 1979). Airborne and radiometric surveys were completed in 1980 (Boniwell, 1981).

Comment (Reference): Primary Reference = Bressler and others, 1979

Comment (Deposit): Model Name = Porphyry Mo (Cox and Singer, 1986; model 16a and 21b)

References

Reference (Ownership): ALASKA KARDEX 063-005

Reference (Deposit): B1246 pp. 228-229

Reference (Deposit): Bright, M.J., 1982, Evaluation of WGM data from Doyon, Ltd.'s McLeod molybdenum prospect: Doyon Report 82-52, 8 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

Reference (Deposit): Boniwell, J.B., 1981, An addendum to the report on airborne geophysics over the McLeod prospect, Kaiyuh Mountains, Nulato, Alaska: Doyon Report 81-08, 16 sheets. (Report held by Doyon, Ltd., Fairbanks, Alaska.)

Reference (Deposit): Boniwell, J.B., 1981, Airborne geophysics over the McLeod prospect, Kaiyuh Mountains, Nulato, Alaska: Doyon Report 81-05, 9 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

Reference (Deposit): Lessman, J., 1979, Doyon project 1979 annual progress report: Doyon Report 79-31, 5 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

Reference (Deposit): Bressler, J., Cleveland, G., Ruzicka, J., 1979, 1979 annual progress report McLeod project area: Doyon Report 79-33, 48 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

Reference (Deposit): Andrews, Tom, Enns, S., and Ruzicka, J., 1978, McLeod project area report, Doyon project 1978: Doyon Report 78-32, 11 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

Reference (Deposit): Cobb, E.H., 1972, Metallic mineral resources map of the Unalakleet quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-427, 1 sheet, scale 1:250,000.

Reference (Deposit): Fields, E.D., 1976, Regional mineral survey of the Kaltag withdrawal area (Doyon, Ltd.) and examination of the McLeod molybdenum prospect, Kaltag, Alaska: Doyon Report 76-21, 9 p. (Report held by Doyon, Ltd., Fairbanks, Alaska).

Reference (Deposit): West, W.S., 1954, Reconnaissance for radioactive deposits in the lower Yukon-Kuskokwim region, Alaska, 1952: U.S. Geological Survey Circular 328, 10 p.

Reference (Deposit): Mertie, J.B., Jr., 1937, The Kaiyuh Hills, Alaska: U.S. Geological Survey Bulletin 868-D, p. 145-177.

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