Montezuma (Threeman Mining Co.)

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

Geologic information

Identification information

Deposit ID 10097488
MRDS ID A010421
Record type Site
Current site name Montezuma (Threeman Mining Co.)
Related records 10209811

Geographic coordinates

Geographic coordinates: -146.5706, 60.86153 (WGS84)
Relative position The Montezuma prospect is at an elevation of about 1500 feet, about 0.5 mile southeast of Copper Mountain. It is in the N1/2 sec. 1, T. 12 S., R. 8 W., of the Copper River Meridian. The site location is accurate to within 1000 ft. This prospect is shown as site C-76 in Jansons and others (1984) and as site #13 in Cobb (1972: MF-392).
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Pyrrhotite Ore
Quartz Gangue

Mineral occurrence model information

Model code 90
USGS model code 24a
Deposit model name Massive sulfide, Cyprus
Mark3 model number 11

Host and associated rocks

  • Host or associated Associated
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Siltstone
    Rock unit name Orca Group
    Rock description Orca Group
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Pliocene
  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock
    Rock unit name Orca Group
    Rock description Orca Group

Nearby scientific data

(1) -146.5706, 60.86153

Comments on the geologic information

  • Geologic Description = The country rocks at this prospect are mafic volcanic rocks and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). The deposit consists of irregular lenses of quartz, chalcopyrite, pyrite, and pyrrhotite in several highly mineralized shear zones in the volcanic rocks (Mihelich and Wells, 1957).? A sample from a quartz-filled shear zone one foot wide in volcanic rocks contained 0.5% Cu, 0.08 oz. Ag/ton, and 0.18 oz. Au/ton (Mihelich and Wells, 1957). Jansons and others (1984) report that chip samples contained 0.74% to 3.2% Cu, 3.2 ppm to 20 ppm Ag, and grab samples contained 125 ppm to 0.75% Cu, and 0.92 ppm to 10 ppm Ag.
  • Age = Tertiary based on the age of the host rocks.

Economic information

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name Copper River

Comments on the reserve resource information

  • Reserves = Inferred reserves of 200 tons @ 1.67% Cu and 9.88 ppm Ag (Jansons and others, 1984).

Comments on the workings information

  • Workings / Exploration = Mihelich and Wells (1957) report more than 300 feet of underground workings and 900 feet of surface stripping. A sample from a quartz-filled shear zone one foot wide in volcanic rocks contained 0.5% Cu, 0.08 oz. Ag/ton, and 0.18 oz. Au/ton (Mihelich and Wells, 1957). Jansons and others (1984) report that chip samples contained 0.74% to 3.2% Cu, 3.2 ppm to 20 ppm Ag, and grab samples contained 125 ppm to 0.75% Cu, and 0.92 ppm to 10 ppm Ag.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS A010421
USGS Alaska Resource Data File ARDF CV017

Bibliographic references

  • Deposit

    Mihelich, M., and Wells, R.R., 1957, Copper mines and prospects adjacent to Landlocked Bay, Prince William Sound, Alaska: U.S. Bureau of Mines Report of Investigations RI 5320, 21 p.

  • Deposit

    Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, Southcentral Alaska: U.S. Bureau of Mines Open-File Report 5-84, 218 p., 2 sheets, scale 1:250,000.

  • Deposit

    Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1992, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska: Economic Geology, v. 87, p. 1722-1746.

  • Deposit

    Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska-A reply: Economic Geology, v. 88, p. 1285-1288.

  • Deposit

    Sainsbury, C.L., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska, A discussion: Economic Geology, v. 88, p. 1284-1285.

  • Deposit

    Cobb, E.H., 1972, Metallic mineral resources map of the Cordova quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-392, 1 sheet, scale 1:250,000.

  • Deposit

    Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.

Comments on the references

  • Primary Reference = Jansons and others, 1984

General comments

Subject category Comment text
Deposit Model Name = Cyprus massive sulfide (Cox and Singer, 1986; model 24a)
Deposit Other Comments = Nelson and others (1985) interpret the country rocks as accreted ocean crust. Crowe and others (1992; 1993) and Sainsbury (1993) discuss the genesis of the volcanogenic massive sulfide deposits in this area.? Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.

Reporter information

Type Date Name Affiliation Comment
Reporter 10-JUN-00 S.W. Nelson U.S. Geological Survey