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Baultoff

Prospect in Alaska, United States with commodities Copper, Molybdenum, Silver, Gold
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Ore body information
  13. Economic information about the deposit and operations
  14. Mining district
  15. Mineral rights holdings
  16. Land status
  17. Ownership information
  18. Reserves and resources
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10210123
MRDS ID A011423
MAS/MILS ID 0020780041
Record type Site
Current site name Baultoff
Alternate or previous names Baultoff Creek

Geographic coordinates

Point of reference Ore Body
Geographic coordinates: -141.21838, 62.10512 (WGS84)
Elevation 1554
Location accuracy 500(meters)
Relative position This prospect is at an elevation of about 5,100 feet on a low ridge along the east side of a small south tributary valley to Baultoff Creek. It is 4,500 feet northwest of peak 6142 and 6,500 feet northeast of peak 7821. The site is in the SW1/4 of section 21, T. 4 N., R. 23 E. of the Copper River Meridian. This is locality 4 of Richter and others (1973), locality 53 of Richter and others (1975), and National Park Service locality WRST-87 (unpublished data). Cobb and Richter (1980) included this prospect under the name 'Baultoff'. It is located to within a few hundred feet.

Site location context

Political divisions (FIPS codes)

Southeast Fairbanks(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Nabesna A-1(quadrangle 1:63,360 scale)

Nabesna SE(quadrangle 1:100,000 scale)

Nabesna(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Alaska(hydrologic region)

Federal lands

Wrangell-St. Elias National Preserve(National Preserve)

National Preserve NPS(Type of land area)

NPS(Federal land areas administered by NPS)

Geographic areas

Country State
United States Alaska

Public Land Survey System information

Meridian Township Range Section Fraction State
Copper River 004 N 023 E 21 NENWNW Alaska

Commodities

Commodity Importance
Copper Primary
Molybdenum Tertiary
Silver Tertiary
Gold Tertiary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Albite Gangue
Quartz Gangue
Actinolite Gangue
Sericite Gangue
Bornite Unknown
Magnetite Unknown

Alteration

  • (Local) Gypsiferous

Mineral occurrence model information

Model code 53
USGS model code 17
Deposit model name Porphyry Cu
Mark3 model number 4
Model code 79
USGS model code 21a
Deposit model name Porphyry Cu-Mo
Mark3 model number 2

Host and associated rocks

  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
    Rock unit name Klein Creek Batholith
    Stratigraphic age (youngest) Cretaceous
    Chronological age 114
    Dating method K-Ar

Nearby scientific data

Ore Body (1) -141.21838, 62.10512
ListMap

Economic information

Ore body information

  • Field Value
    Type of Orebody #1 STOCKWORK
    Shape of Orebody #1 IRREGULAR
    Type of Orebody #2 DISSEMINATED
    Shape of Orebody #2 MASSIVE
    Primary mode of Origin HYDROTHERMAL
    Primary Ore Control IGNEOUS
    Date of Last Modification 860825

Comments on the geologic information

  • Original Alteration entry - Potassic, propylitic; extensive. Locally gypsiferous alteration composed of central altered zone 400 m by 1000 m with chlorite,sericite, and albite cut by late stage anhydrite veins. Outer altered zones characterized by intense sericitization and pyritization.
  • Most recent Alteration = A 400- by 1,000-meter central altered zone is characterized by albite, chlorite, sericite and late anhydrite veins. It is within a 2,000- by 3,000-meter outer zone marked by abundant sericite and pyrite. Local actinolite veins and disseminations are present in the alteration zones. A post-mineralization fault bounds the alteration zone to the east (Richter and others, 1973).
  • Geologic Description = At the Baultoff prospect, disseminated pyrite and chalcopyrite occur in hornblende diorite and quartz porphyry of the mid-Cretaceous, Klein Creek pluton (Matson and Richter, 1971 [OFR 71-202]: Richter and others, 1975; Hollister and others, 1975). A 400- by 1,000-meter central altered zone is characterized by albite, chlorite, sericite and late anhydrite veins. It is within a 2,000- by 3,000-meter outer zone marked by abundant sericite and pyrite. Local actinolite veins and disseminations are present in the alteration zones. A post-mineralization fault bounds the alteration zone to the east. Surface samples contain less than 0.25 percent copper, and average 0.10 percent copper and less than 0.01 percent molybdenum (Richter and others, 1975). Low amounts of gold and silver are also present. The deposit is estimated to contain 160 million tons with an average grade of 0.20 percent copper and very low amounts of molybdenum (Richter and others, 1975). The diorite and porphyry that host the deposit are part of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic
Deposit size Medium
Significant Yes

Mining district

District name Chisana

Mineral rights holdings

Type of mineral rights Located Claim

Land status

Ownership category Federal

Ownership information

  • Type Owner
    Owner Gerald Wood
    Year 1984

Reserves and resources

  • Type In-situ
    Estimate year 1979
    Inferred 145100000mt ore
    Total resources 145100000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.2 wt-pct Copper Trace 1979

Comments on the reserve resource information

  • Reserves = The deposit is estimated to contain 160 million tons with an average grade of 0.20 percent copper and very low amounts of molybdenum (Richter and others, 1975).

Comments on the workings information

  • Workings / Exploration = Surface exploration and some diamond drilling have been used to evaluated this deposit. Average grades from surface sampling: 0.10% Cu, with all samples below 0,25% Cu and less than 0.01% Mo, Au and Ag also present (Richter and others, 1975, USGS MF-655K, loc. 53).

Reference information

Bibliographic references

Comments on the references

  • Primary Reference = Richter, D.H., Singer, D.A., and Cox, D.P., 1975, Mineral resources map of the Nabesna quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-655-K, 1 sheet, scale 1:250,000.

General comments

Subject category Comment text
Age Mid-Cretaceous; the diorite and porphyry that host the deposit are part of the Klein Creek pluton which has a K/Ar date of 111 +/- 3.6 Ma (Richter, Lanphere, and Matson, 1975).
Deposit Other Comments = The prospect is in the Wrangell-St. Elias National Preserve. This is one of 8 known porphyry copper deposits which make up the principal mineral resource potential of Nabesna quadrangle. See also: Orange Hill, Bond Creek, Carl Creek, and Horsfeld.

Reporter information

Type Date Name Affiliation Comment
Reporter 19-FEB-88 Carnes, R. David U.S. Bureau of Mines
Reporter 27-JAN-97 Leonard, K.R. U.S. Geological Survey
Reporter 27-JAN-97 Elliott, R.L. U.S. Geological Survey
Reporter 27-JAN-97 Nokleberg, W.J. U.S. Geological Survey
Reporter 27-JAN-97 Richter, D.H. U.S. Geological Survey
Reporter 24-NOV-02 Hudson, Travis L. Applied Geology

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.