Dunka Pit Cu-Ni deposit

Occurrence in St. Louis county in Minnesota, United States with commodities Copper, Nickel, Cobalt, Platinum, Palladium
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. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Ore body information
  13. Controls for ore emplacement
  14. Economic information about the deposit and operations
  15. Mining district
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10048523
MRDS ID MP00113
Record type Site
Current site name Dunka Pit Cu-Ni deposit

Geographic coordinates

Geographic coordinates: -91.82434, 47.72083 (WGS84)
Elevation 457
Relative position ABOUT 5 MI NORTHEAST OF BABBITT

Site location context

Political divisions (FIPS codes)

St. Louis(county)

Minnesota(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Babbitt NE(quadrangle 1:24,000 scale)

Ely(quadrangle 1:100,000 scale)

Two Harbors(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Rainy Headwaters(hydrologic unit)

Rainy(hydrologic accounting unit)

Rainy(hydrologic subregion)

Souris-Red-Rainy(hydrologic region)

Federal lands

Superior National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Minnesota St. Louis

Public Land Survey System information

Meridian Township Range Section Fraction State
4th Principal 060N;061N 012W;012W Minnesota

Commodities

Commodity Importance
Copper Primary
Nickel Critical Primary
Cobalt Critical Tertiary
Platinum Critical Tertiary
Palladium Critical Tertiary

Materials information

Materials Type of material
Bornite Ore
Chalcopyrite Ore
Cubanite Ore
Millerite Ore
Pentlandite Ore
Pyrrhotite Ore
Sphalerite Ore
Olivine Gangue
Plagioclase Gangue
Pyroxene Gangue

Analytical data

Result HIGH GRADE SAMPLE FROM DUNKA PIT CONTAINS 10 PPB PT, 960 PPB PD. WEIGHTED AVERAGES OF COMBINED PT+PD=278 PPB, OF CU=0.47%, OF NI=0.19%. MEDIAN OF PT=PD=290 PPB

Mineral occurrence model information

Model code 9
USGS model code 5a
Deposit model name Duluth Cu-Ni-PGE

Host and associated rocks

  • Host or associated Associated
    Rock type Sedimentary Rock > Chemical Sediment > Iron Formation
    Rock unit name Biwabik Formation
    Stratigraphic age (youngest) Paleoproterozoic
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro > Troctolite
    Rock unit name South Kawishiwi Intrusion
    Stratigraphic age (youngest) Mesoproterozoic

Nearby scientific data

(1) -91.82434, 47.72083

Economic information

Geologic structures

Type of structure Local
Structure description Several Ne-Trending Normal Faults Parallel The Midcontinent Rift System Near The Margin. These Faults Formed During The Opening Of The Rift And Controlled Emplacement Of The Troctolitic And Late Intrusions.

Ore body information

  • General form TABULAR, DISSEMINATED

Controls for ore emplacement

  • Sulfides Segregated In Basal Troctolites Sub-Parallel To Lower Contacts. Faults And Folds Were Responsible For Localizing Sulfide Mineralization As Well As For Providing Conduits For Later Syn- To Post-Magmatic Hydrothermal Fluids.

Comments on the geologic information

  • DULUTH GABBROS EMPLACED IN RIFT-RELATED VOIDS AND GRABENS. TROCTOLITIC LAST GABBROS FORM BASAL CONTACT

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic
Deposit size Large
Significant No

Mining district

District name Western Margin Duluth Complex

Comments on development

  • NUMEROUS DRILL HOLES FROM SEVERAL MINING COMPANIES, INCLUDING NEWMONT

Reference information

Bibliographic references

  • Deposit

    CANNON, W.F., 1991, WRITTEN COMMUN. TO M.L. ZINETEK

  • Deposit

    MORTON, PENELOPE, AND HAUCK, S.A., 1987, PGE, AU AND AG CONTENTS OF CU-NI SULFIDES FOUND AT THE BASE OF THE DULUTH COMPLEX, NORTHEASTERN MINNESOTA: NATURAL RESOURCES RESEARCH INSTITUTE TECHNICAL REPORT NRRI/GMIN-TR-87-04, 81 P.

General comments

Subject category Comment text
Deposit SPECIFIC SIZE INFORMATION NOT AVAILABLE FOR THIS DEPOSIT BUT IT IS PRESUMED LARGE LIKE OTHERS IN DULUTH COMPLEX
Deposit SULFIDES ORIGINATED AS INTERCUMULATE IN LITHIFYING TROCTOLITE WHEN SULFUR WAS INTRODUCED INTO LIQUID FRACTION CREATING IMMISCIBLE SUFLIDE AND SILICATE LIQUIDS. HIGHER DENSITY OF SULFIDE AND BASAL INTRODUCTION OF SULFUR CREATED BASAL LOCALIZATION. VARIATION IN SULFUR SOURCE, PATHWAYS, AND FAULTING CREATED LOCAL VARIATION AND HIGHER HORIZONS. SEE MORTON AND HAUCK (1987) FOR FURTHER ANALYTICAL DATA. ; INFO.SRC : 1 PUB LIT; 2 UNPUB REPT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-1991 Peterson, Jocelyn A. U.S. Geological Survey
Editor 28-FEB-2005 Woodruff, L.G. U.S. Geological Survey

Beyond USGS

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