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Rietfontein Chrome Mine

Producer in South Africa with commodities Chromium, PGE, Iron, Silica
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Alteration
  8. Host and associated rocks
  9. Nearby scientific data
  10. Geologic structures
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Ownership information
  17. Production statistics
  18. Reserves and resources
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10089694
MRDS ID W028408
Record type Site
Current site name Rietfontein Chrome Mine

Geographic coordinates

Geographic coordinates: 27.36812, -25.7133 (WGS84)
Elevation 1158
Relative position 13 KILOMETERS SOUTHEAST OF THE TOWN OF RUSTENBURG

Site location context

Political divisions (FIPS codes)

South Africa(country)

Africa(continent)

Land(continent)

Geographic areas

Country
South Africa

Commodities

Commodity Importance
Chromium Critical Primary
PGE Critical Secondary
Iron Secondary
Silica Secondary

Materials information

Materials Type of material
Chromite Ore
Magnetite Ore
Anorthosite Gangue
Chalcopyrite Gangue
Pentlandite Gangue
Pyrrhotite Gangue

Alteration

  • (Local) Surface And Near-Surface Alteration Of Feldspathic Materials Only

Analytical data

Result LUMP ORE: - 100 MM PLUS 25 MM: CR2O3 41.0 %, CR: FE 1.50 - 1.56:1 CONCENTRATES: SIZE: - 1 MM
Result CR2O3 45.5 %, SIO2 1.8 %, FEO 25.0 % MGO 10.0 %, CAO 0.2 - 0.3 %, CR - FE 1.50 - 1.56:1

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock
    Rock unit name Bushveld Igneous Complex (Including The Overlying Merensky Reef)
    Rock description Bushveld Igneous Complex (Including The Overlying Merensky Reef)
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro

Nearby scientific data

(1) 27.36812, -25.7133
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Inward-Dipping Cone-Like Structure, Folding And Faulting (Including Low-Angle Thrusting) Exists, But Are Of Minor Importance; Erosion, Peneplanation And Build-Up Of Younger Sediments Are Basic Criteria Regionally.
Type of structure Local
Structure description The Area'S Upper, Middle And Lower Chrome Groups (Underlying The Merensky Reef) Are Extraordinarily Uniform As To Composition And Thickness. Faults And Folds, Locally, Are Of Minor Importance Only. Seam Undulations, However, Are Common And Thus Present Localized (Albeit Moderate) Changes In The Dip.

Ore body information

  • General form TABULAR/BLANKET
    Strike E-W
    Dip 12 DEG N
    Thickness 1.3M

Controls for ore emplacement

  • The Various Components Of The Bushveld Igneous Complex Have Been Emplaced In Successive Eruptions As Sheet-Like Masses Into The Pretoria Series Volcanics (Transvaal System), And In Some Cases Into One Another, Dipping Inward Toward The Center Giving A Cone-Like Structure To The Complex As A Whole.

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Medium
Significant No
Discovery year 1949
Year of first production 1953

Mining district

District name Rustenburg (Western) Belt; Bushveld Igneous Complex

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Chrome Chemicals S. A. (Pty) Ltd
  • Type Owner
    Owner J. G. Farbenfabrieken, Bayer; Federal Republic Of Germany

Production statistics

  • Year 1978
    Material CON CR
    Accuracy Estimate
    Description Ap_Grade: ^46 % Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 46wt-pct
  • Year 1978
    Material ORE CR
    Accuracy Estimate
    Description Ap_Grade: ^41 % Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Ore Chromium Chromium 41wt-pct
  • Year 1979
    Material CON CR
    Accuracy Estimate
    Description Ap_Grade: ^46% Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 46wt-pct
  • Year 1979
    Material ORE CR
    Accuracy Estimate
    Description Ap_Grade: ^41% Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Ore Chromium Chromium 41wt-pct
  • Year 1980
    Material CON CR
    Accuracy Estimate
    Description Ap_Grade: ^46% Cr2o3 Approximately
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 46wt-pct
  • Year 1980
    Material ORE CR
    Accuracy Estimate
    Description Ap_Grade: ^41% Cr2o3 Approximately
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Ore Chromium Chromium 41wt-pct
  • Year 1981
    Period 1953-1981
    Material CON CR
    Accuracy Estimate
    Description Cp_Grade: ^46 % Cr2o3 Approx
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 46wt-pct
  • Year 1981
    Period 1953-1981
    Material ORE CR
    Accuracy Estimate
    Description Cp_Grade: ^41 % Cr2o3 Approx
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Ore Chromium Chromium 41wt-pct

Comments on the production information

  • NO PRODUCTION DATA AVAILABLE SINCE 1981

Reserves and resources

  • Type In-situ
    Estimate year 1975
    Total resources 155000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Chromium Cr2O3 40 wt-pct Chromium Major 1975

Comments on the reserve resource information

  • INDICATED RESERVES TO A VERTICAL DEPTH OF 127 METERS

Comments on the workings information

  • SEE DESCRIPTION OF DEPOSIT COMMENTS. MINING IS BY DEVELOPMENT DRIFTS AND INCLINES IN ORE TO CREATE MODIFIED ROOM AND PILLAR METHOD. BROKEN ORE IS MOVED DOWNWARD INTO ORE PASSES BY SLUSHER AND HAND TRAMMED VIA MAIN HAULAGE DRIFTS TO INCLINE SHAFTS FOR CONVEYOR HAULAGE TO THE SURFACE. TWO SHAFTS ARE CURRENTLY IN OPERATION. WASTE IS BACK-FILLED UNDERGROUND. SURFACE FACILITIES CONSIST OF HAND SORTING TABLES, SCREENS; BALL MILLS, VIBRATORY TABLES AND WASHING.

Comments on development

  • THE PRESENT OPERATOR ASSUMED CONTROL OF THIS MINE IN 1955 . EARLIER DEVELOPERS DATE BACK TO 1949 . ; MILL.CAP: 0.2 MIL. MET T/YR ; ECON.COM: A MEDIUM-SIZED OPERATION; DEPENDENT UPON EXPORT SALES ONLY. GIVEN CAPTIVE NATURE OF SALES (TO BAYER, WEST GERMANY), THE MINE'S LONG-RANGE OUTLOOK IS FAVORABLE AS A SUPPLIER OF CHEMICAL GRADE ORE AND CONCENTRATES AT THE CURRENT PRODUCTION LEVEL.

Reference information

Bibliographic references

  • Analytical Data

    SRC.REF: FERROUS AND NONFERROUS MINES AND WORKS IN SOUTH AFRICA; MINERALS BUREAU; DIRECTORY NO. 3/79

  • Deposit

    MINERALS RESOURCES OF THE REPUBLIC OF SOUTH AFRICA, FIFTH EDITION, HANDBOOK 7, GEOLOGICAL SURVEY, DEPARTMENT OF MINES, 1976.

  • Deposit

    CHROMITE MINES AND RESOURCES IN THE REPUBLIC OF SOUTH AFRICA; UNIVERSITY OF IDAHO FOR M.A.S., US BUREAU OF MINES; SIEMS, P., CRIST, E. M. AND SHEEHAN, L. E. JR., 1976 .

  • Deposit

    MARKETING DIRECTORY NO. 2 , FERROUS AND NONFERROUS METALS AND MINERALS IN SOUTH AFRICA; MINERALS BUREAU, DEPARTMENT OF MINES; 1977 .

  • Deposit

    OPERATING MINES IN THE REPUBLIC OF SOUTH AFRICA; MINERALS BUREAU, DEPARTMENT OF MINES; DIRECTORY NO. 1/79 ; 1979 .

  • Deposit

    "THE CHROMITE DEPOSITS IN THE RUSTENBURG AREA"; DEPARTMENT OF MINES, GEOLOGICAL SURVEY; BULLETIN 27 ; FOURIE, G.P.; 1959 . "THE CHROMITE DEPOSITS OF THE BUSHVELD IGNEOUS COMPLEX"; DEPARTMENT OF MINES, GEOLOGICAL SURVEY; KUPFERBURGER, W. AND LOMBAARD B. V. 1937

  • Production

    REPORTER'S ESTIMATES BASED ON INDUSTRY INDICATORS AND OFFICIAL (MINERALS BUREAU) COUNTRY TOTALS ; REPORTER'S ESTIMATES BASED ON INDUSTRY INDICATORS AND OFFICIAL (MINERALS BUREAU) COUNTRY TOTALS. ; REPORTERS ESTIMATED BASED ON INDUSTRY INDICATORS AND OFFICIAL (MINERALS BUREAU) COUNTRY TOTALS

General comments

Subject category Comment text
Deposit INFORMATION MERGED FROM RECORD NUMBER W028904 ; W030785 ; W032258 ; W055324
Deposit MAX. THICKNESS REFERS TO THE "MAIN SEAM" OF THE "LOWER GROUP" OF SEAMS IN THE "CRITICAL ZONE" OF THE BUSHVELD IGNEOUS COMPLEX. ADDITIONALLY, THE "LEADER SEAM" AT 0.30 METER (NOT CURRENTLY RECOVERED), OCCURS 0.4 METER ABOVE THE "MAIN SEAM". THE "ROAMER HORIZON" (UNECONOMIC) OCCURS BELOW THE "MAIN SEAM" WITH 6 - 8 THIN SEAMS CONTAINED. DEPTHS TO TOP AND BOTTOM (AND MAXIMUM LENGTH OF OREBODY) NOT KNOWN.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-AUG-1979 Sweetwood, Charles W. Department of State
Updater 01-JUL-1982 Mccarter, Lorna D. Department of State
Updater 01-MAY-1980 Sweetwood, Charles W. Department of State
Updater 01-JUL-1981 Mccarter, Lorna D. Department of State
Updater 01-JUL-1982 Mccarter, Lorna D. Department of State
Updater 01-JUL-1987 Mccarter, Lorna D. Department of State

Beyond USGS

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

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