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Maturi Nokomis Deposit

Prospect in Lake county in Minnesota, United States with commodities Copper, Nickel, Palladium, Platinum, Cobalt, Titanium, 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. 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. Ownership information
  17. Reserves and resources
  18. Workings at the site
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10096418
MRDS ID W018671
Record type Site
Current site name Maturi Nokomis Deposit
Alternate or previous names South Kawishiwi River West, Duval, Maturi Deep, Inco South Lease, Inco Test Shaft Site

Geographic coordinates

Point of reference Ore Body
Geographic coordinates: -91.75572, 47.80138 (WGS84)
Location accuracy 100(meters)
Relative position About 11 miles NE of Babbitt, MN, 8.5 miles SE of Ely MN.

Site location context

Political divisions (FIPS codes)

Lake(county)

Minnesota(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Kangas Bay(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 Lake

Public Land Survey System information

Meridian Township Range Section Fraction State
4th Principal 061N;062N 011W;011W 04,05,08,09;33,34 Minnesota

Comments on the location information

  • Maps at the Duluth Metals website portray Maturi and Nokomis as the same polygon. Leaders from the western part of the orebody are described as Maturi and from the eastern part as Nokomis.

Commodities

Commodity Importance
Copper Primary
Nickel Critical Primary
Palladium Critical Primary
Platinum Critical Primary
Cobalt Critical Secondary
Titanium Critical Secondary
Gold Secondary

Comments on the commodity information

  • PGE MINERALIZATION IS KNOWN TO OCCUR ONLY ALONG THE WESTERN CONTACT OF THE 1.1 GA DULUTH COMPLEX. SULFIDES ARE DISSEMINATED OR IN VEINLETS, INTERGROWN WITH SILICATES, FORMED BY MAGMATIC SEGREGATION.

Materials information

Materials Type of material
Bornite Ore
Chalcocite Ore
Chalcopyrite Ore
Covellite Ore
Cubanite Ore
Cuprite Ore
Digenite Ore
Pentlandite Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Tenorite Ore
Olivine Gangue
Plagioclase Gangue
Pyroxene Gangue

Analytical data

Result ANALYSES OF CORE SAMPLES BY USBM INDICATED 0.016-0.215 % CU, 0.045-0.077% NI. SURFACE SAMPLES FOR MATURI AND SPRUCE RAN 0.21-1.12% CU, 0.06-0.38% NI. WEIGHTED AVERAGE FOR COMBINED PT AND PD=570 PPB, FOR AU=91 PPB, FOR CU=0.66%, FOR NI=0.24%. WHOLE ROCK CONCENTRATIONS FROM ORE ZONE ROCKS RAN 53 PPB OS, 88 PPB IR, 210 PPB RU, 172 PPB RH, 1300 PPB PT, 710 PPB PD, AND 38 PPB AU. ASSAYS OF FLOTATION CONCENTRATES RAN 0.4 OZ/TON AU, 1.1-1.5 OZ/TON AG, 0.021-0.036 OZ/TON PT, 0.120-0.128 OZ/TON PD, 0.002-0.003 OZ/TON RH, 0.001-0.002 OZ/TON IR, 0.001-0.004 OZ/TON RU

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 Plutonic Rock > Granitoid > Granite
    Rock unit name Giants Range Batholith
    Stratigraphic age (youngest) Neoarchean
    Stratigraphic age (youngest) Neoarchean
  • 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

Ore Body (1) -91.75572, 47.80138
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Faulting Related To Rift Origin Of Duluth Complex. 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 DISSEMINATED, VEINLETS, SULFIDE-SILICATE INTERGROWTHS
    Strike N35E
    Dip 25 SE
    Thickness 100M
    Length 4000M
    Width 1600M
    Area 1000HA
    Depth to top 0M

Controls for ore emplacement

  • Sulfides Segretated In Basal Troctolites Sub-Parallel To Lower Contacts

Comments on the geologic information

  • DULUTH GABBROS AND RELATED INTRUSIONS EMPLACED IN RIFT-RELATED VOIDS AND GRABENS IN OLDER ROCKS. TROCTOLITIC LAST GABBROS FORM BASAL CONTACT. THE DULUTH COMPLEX IS A LARGE, COMPOSITE THOLEIITIC MAFIC INTRUSION THAT WAS EMPLACED INTO COMAGMATIC FLOOD BASALTS ALONG A PORTION OF THE MIDDLE PROTEROZOIC (1.1 GA, KEWEENAWAN) MIDCONTINENT RIFT SYSTEM. IN THE SOUTH KAWISHIWI INTRUSION, SULFIDES FORM A DISCRETE ZONE UNDERLYING SULFIDE-FREE ROCKS. MOST SULFIDES OCCUR INTERSTITIALLY BETWEEN EUHEDRAL OLIVINE OR PLAGIOCLASE OR ARE INCLUDED IN THE RIMS OF SILICATES. THE SULFIDES FORMED AFTER MOST SILICATES HAD ACCUMULATED.
  • FAULTS AND FOLDS WERE RESPONSIBLE FOR LOCALIZING SULFIDE MINERALIZATION AS WELL AS FOR PROVIDING CONDUITS FOR LATER SYN- TO POST-MAGMATIC HYDROTHERMAL FLUIDS. SULFIDES SEGREGATED IN BASAL TROCTOLITES SUB-PARALLEL TO LOWER CONTACTS

Economic information about the deposit and operations

Development status Prospect
Commodity type Metallic
Deposit size Large
Significant Yes
Discoverer International Nickel Co.

Mining district

District name Western Margin Duluth Complex

Ownership information

  • Type Operator
    Owner Duval
  • Type Owner
    Owner State of MN
    Interest 100
    Year 1975
  • Type Operator
    Owner INCO
    Year 1975

Reserves and resources

  • Type In-situ
    Estimate year 1977
    Total resources 1043mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper Cu 0.5 wt-pct Copper Major 1977
    Nickel Ni 0.76 wt-pct Nickel Major 1977
  • Type In-situ
    Name Maturi
    Estimate year 2009
    Proved 83000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Copper 0.7 wt-pct Copper Primary 2009
    Nickel 0.26 wt-pct Nickel Primary 2009
    Platinum 0.2 g/mt PGE Primary 2009
    Palladium 0.1 g/mt PGE Primary 2009
    Gold 0.1 g/mt Gold Secondary 2009
  • Type In-situ
    Name Nokomis
    Estimate year 2009
    Indicated 449000000mt ore
    Remarks Precious metals grade is stated as 0.6 g/t TPM. Metal ratios are 2.3 Pt, 5.17 Pd, 1.21 Au.
    Commodity Subtype Grade units Group Importance Year
    Copper 0.624 wt-pct Copper Primary 2009
    Nickel 0.199 wt-pct Nickel Primary 2009
    Palladium 0.36 g/mt PGE Primary 2009
    Platinum 0.16 g/mt PGE Primary 2009
    Gold 0.08 g/mt Gold Secondary 2009
  • Type In-situ
    Name Nokomis
    Estimate year 2009
    Inferred 284000000mt ore
    Remarks Precious metals grade is stated as 0.697 g/t TPM. Metal ratios are 1.75 Pt, 3.94 Pd, 0.88 Au.
    Commodity Subtype Grade units Group Importance Year
    Copper 0.627 wt-pct Copper Primary 2009
    Nickel 0.194 wt-pct Nickel Primary 2009
    Palladium 0.475 g/mt PGE Primary 2009
    Platinum 0.211 g/mt PGE Primary 2009
    Gold 0.106 g/mt Gold Secondary 2009

Comments on the reserve resource information

  • ANALYSES OF CORE SAMPLES BY USBM INDICATED 0.016-0.215 % CU, 0.045-0.077% NI. SURFACE SAMPLES FOR MATURI AND SPRUCE RAN 0.21-1.12% CU, 0.06-0.38% NI. WEIGHTED AVERAGE FOR COMBINED PT AND PD=570 PPB, FOR AU=91 PPB, FOR CU=0.66%, FOR NI=0.24%. WHOLE ROCK CONCENTRATIONS FROM ORE ZONE ROCKS RAN 53 PPB OS, 88 PPB IR, 210 PPB RU, 172 PPB RH, 1300 PPB PT, 710 PPB PD, AND 38 PPB AU. ASSAYS OF FLOTATION CONCENTRATES RAN 0.4 OZ/TON AU, 1.1-1.5 OZ/TON AG, 0.021-0.036 OZ/TON PT, 0.120-0.128 OZ/TON PD, 0.002-0.003 OZ/TON RH, 0.001-0.002. OZ/TON IR, 0.001-0.004 OZ/TON RU. FROM MORTON AND HAUCK, 1989, 1987; WEIBLEN, 1989; SCHLUTER AND LANDSTROM, 1976.

Workings at the site

  • Type of workings Surface
    Area 259.008HA
    Overall length 3657.6M
    Overall width 1600M

Comments on development

  • DISCOVERY OF DEPOSIT WAS A RESULT OF GEOLOGIC MAPPING, GEOPHYSICS, GEOCHEMISTRY, AND CORE DRILLINGS. MINERALIZATION IN AREA WAS SAMPLED BY USBM IN 1951 ; ECON.COM: ENVIRONMENTAL CONSIDERATIONS. MINING-ORIENTED IRON RANGE NEARBY

Reference information

Bibliographic references

  • Commodity

    BONNICHSEN, BILL, 1974, COPPER AND NICKEL RESOURCES IN THE DULUTH COMPLEX: MINNESOTA GEOLOGICAL SURVEY INFORMATION CIRCULAR 10, 24 P.

  • Reserve-Resource

    http://www.pdac.ca/pdac/conv/2009/pdf/core-shack/cs-nokomis.pdf

  • Reserve-Resource

    http://www.duluthmetals.com/i/pdf/DM-PDAC-February-2009.pdf

  • Deposit

    GROSH, W.A., PENNINGTON, J.W., WASSON, P.A., AND COOKE, S.R.B., 1955, INVESTIGATION OF COPPER-NICKEL MINERALIZATION IN KAWISHIWI RIVER AREA, LAKE COUNTY, MINN.: U.S. BUREAU OF MINES REPORT OF INVESTIGATIONS 5177, 18 P.

  • Geology

    SCHWARTZ, G.M., AND DAVIDSON, D.M., 1952, GEOLOGIC SETTING OF THE COPPER-NICKEL PROSPECT IN THE DULUTH GABBRO NEAR ELY, MINNESOTA: MINING ENGINEERING, V. 4, NO. 7, P. 699-702.

  • Geology

    MORTON, PENELOPE, AND HAUCK, S.A., 1989, PRECIOUS METALS IN THE COPPER-NICKEL DEPOSITS OF THE DULUTH COMPLEX, IN MOREY, G.B., ED., WORKSHOP ON THE APPLICABILITY OF GOLD AND PLATINUM-GROUP-ELEMENT MODELS IN MINNESOTA: MINNESOTA GEOLOGICAL SURVEY INFORMATION CIRCULAR 30, P. 47-48.

  • Geology

    WEIBLEN, P.W., 1989, THE IMPORTANCE OF EVALUATING THE POTENTIAL OF THE DULUTH COMPLEX AS A PLATINUM GROUP ELEMENT RESOURCE, IN MOREY, G.B., ED., WORKSHOP ON THE APPLICABILITY OF GOLD AND PLATINUM-GROUP-ELEMENT MODELS IN MINNESOTA: MINNESOTA GEOLOGICAL SURVEY INFORMATION CIRCULAR 30, P. 51-55.

  • Geology

    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.

  • Development

    SCHLUTER, R.B., AND LANDSTROM, A.B., 1976, CONTINUOUS PILOT PLANT TESTING CONFIRMS FLOATABILITY OF DULUTH COMPLEX SULPHIDES: ENGINEERING AND MINING JOURNAL, V. 177, NO. 4, P. 80-83.

  • Geology

    LISTERUD, W.H., AND MEINEKE, D.G., 1977, MINERAL RESOURCES OF A PORTION OF THE DULUTH COMPLEX AND ADJACENT ROCKS IN ST. LOUIS AND LAKE COUNTIES, NORTHEASTERN MINNESOTA: MINNESOTA DEPARTMENT OF NATURAL RESOURCES, DIVISION OF MINERALS, MINERALS EXPLORATION SECTION, REPORT 93, 74 P.

  • Deposit

    PAGE, N. J, 1986, DESCRIPTIVE MODEL OF DULUTH CU-NI-PGE, IN COX, D.P. AND SINGER, D.A., MINERAL DEPOSIT MODELS: U.S. GEOLOGICAL SURVEY BULLETIN 1693, P. 16.

  • Geology

    FOOSE, M.P., 1985, THE SETTING AND DISTRIBUTION OF COPPER-NICKEL SULFIDES IN THE SOUTH KAWISHIWI INTRUSION, DULUTH COMPLEX, MINNESOTA, IN KRAFT, KATHLEEN, ED., U.S. GEOLOGICAL SURVEY RESEARCH ON MINERAL RESOURCES--1985, PROGRAM AND ABSTRACTS: U.S. GEOLOGICAL SURVEY CIRCULAR 949, P. 12-13.

  • Geology

    HAUCK, S.A., SEVERSON, M.J., ZANKO, L., BARNES, S-J., MORTON, P., ALMINAS, H., FOORD, E.E., AND DAHLBERG, E.H., 1997, AN OVERVIEW OF THE GEOLOGY AND OXIDE, SULFIDE AND PLATINUM-GROUP ELEMENT MINERALIZATION ALONG THE WESTERN AND NORTHERN CONTACTS OF THE DULUTH COMPLEX: GEOLOGICAL SOCIETY OF AMERICA SPECIAL PAPER, V. 312, PP. 137-185.

General comments

Subject category Comment text
Deposit ORE HORIZON DIPS UNDERGROUND. EXTENT UNKNOWN, SO WIDTH UNDETERMINED. LENGTH ALONG SURFACE ARBITRARILY LIMITED.
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. TEST SAMPLE DISCUSSED BY SCHLUTER AND LANDSTROM IS SAID TO HAVE COME FROM THE MATURI DEPOSIT (M.L. ZIENTEK, WRITTEN COMMUN., 1993) ; INFO.SRC : 1 PUB LIT
Deposit RECORD W000708 HAS BEEN DELETED.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JAN-1984 no name U.S. Geological Survey
Updater 01-JAN-1991 Peterson, J.A. U.S. Geological Survey
Reporter 01-JAN-1996 Sutphin, D.M. (Cannon, W.F.) U.S. Geological Survey
Updater 01-MAR-1997 Sutphin, D.M. U.S. Geological Survey
Editor 01-MAY-1997 Mason, Jr., G.T. U.S. Geological Survey
Editor 25-NOV-2003 Woodruff, Laurel G. U.S. Geological Survey Work done in Filemaker
Editor 25-FEB-2005 Woodruff, L.G. U.S. Geological Survey
Reporter 04-MAY-2009 Schruben, Paul U.S. Geological Survey Reserves
Editor 14-SEP-2009 Nicholson, Suzanne U.S. Geological Survey

Beyond USGS

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

Operator history (post-MRDS)

MRDS records operators as of each record's last update (≤ 2019). Some of the operators listed here have since changed hands or dissolved:

  • INCO — acquired by Subsidiary of Vale (2007)
    International Nickel Company; acquired by Brazilian miner Vale in 2007 for ~US$18 B.

Curated by qvyshift.com from publicly-reported M&A activity (SEC filings, press releases, USGS Mineral Yearbooks). Not authoritative — verify against primary sources before relying on it. The MSHA panel above is the current authoritative source for actively-permitted mines.

Maps centered on this site