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Grasvally 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. Workings at the site
  20. Links to other databases
  21. Bibliographic references
  22. General comments
  23. Reporter information

Geologic information

Identification information

Deposit ID 10079234
MRDS ID W028406
Record type Site
Current site name Grasvally Chrome Mine

Geographic coordinates

Geographic coordinates: 28.98475, -24.33001 (WGS84)
Elevation 1158
Relative position 17 KILOMETERS SOUTHWEST OF THE TOWN OF POTGIETERSRUS

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 Tertiary
Iron Tertiary
Silica Tertiary

Materials information

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

Alteration

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

Analytical data

Result LUMP ORE: CR2O3 40.8%, SIO2 12.7%, AL2O3 9.6% FEO 12.1% MGO 15.5% CAO 1.20%, P 0.004%, S 0.045%, CR:FE 2.26:1. CONCENTRATES: CR2O3 48.75%, SIO2 4.55%, AL2O3 11.7% FEO 15.1%, MGO 13.8%, CAO 0.33%, P 0.005%, S 0.045%, CR:FE 2.21:1

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), Zoetveld Subsuite
    Rock description Bushveld Igneous Complex (Including The Overlying Merensky Reef), Zoetveld Subsuite
    Stratigraphic age (youngest) Paleoproterozoic
    Stratigraphic age (youngest) Paleoproterozoic
    Stratigraphic age (youngest) Pliocene
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Pyroxenite

Nearby scientific data

(1) 28.98475, -24.33001
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 See Comments

Ore body information

  • General form TABULAR/BLANKET
    Strike N - S
    Dip 45 DEG W
    Thickness 0.9M
    Length 3000M
    Depth to top 305M

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 Large
Significant No
Discovery year 1961
Year of first production 1962

Mining district

District name Potgietersrus Extension; Bushveld Igneous Complex

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Cromore (Pty) Ltd.
  • Type Owner
    Owner S. A. Manganese Amcor Ltd. (Samancor)

Production statistics

  • Year 1978
    Material CON CR
    Accuracy Estimate
    Description Ap_Grade: ^49% Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 49wt-pct
  • Year 1978
    Material ORE CR
    Accuracy Estimate
    Description Ap_Grade: ^41 % Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Chromium Chromium 41wt-pct
  • Year 1979
    Material CON CR
    Accuracy Estimate
    Description Ap_Grade: ^49% Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 49wt-pct
  • Year 1979
    Material ORE CR
    Accuracy Estimate
    Description Ap_Grade: ^41% Cr2o3 (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Chromium Chromium 41wt-pct
  • Year 1980
    Material CON CR
    Accuracy Estimate
    Description Ap_Grade: ^49% Cr2o3 Approximately
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 49wt-pct
  • Year 1980
    Material ORE CR
    Accuracy Estimate
    Description Ap_Grade: ^41% Cr2o3 Approximately
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Chromium Chromium 41wt-pct
  • Year 1981
    Period 1962-1981
    Material CON CR
    Accuracy Estimate
    Description Cp_Grade: ^49 % Cr2o3 Approx
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Conc. Chromium Chromium 49wt-pct
  • Year 1981
    Period 1962-1981
    Material ORE CR
    Accuracy Estimate
    Description Cp_Grade: ^41 % Cr2o3 Approx
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Chromium Chromium 41wt-pct
  • Year 1982
    Period 1963-1982
    Material ORE
    Accuracy Accurate
    Description Cp_Grade: ^44% Cr2o3
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Cr2O3 Chromium Chromium 44wt-pct

Comments on the production information

  • 1963-1982 PRODUCTION WAS REPORTED FOR THE POTGIETERSRUS SECTOR. ; NO PRODUCTION DATA AVAILABLE. ; NO PRODUCTION FIGURES AVAILABLE. EXCESSIVE FAULTING HAS RESULTED IN DIFFICULT MINING CONDITIONS AND A HIGH RATE OF DEVELOPMENT IS NECESSARY TO REPLACE ORE RESERVES ; MINING RE-ESTABLISHED IN NEW SHALLOWER AREAS IN EFFORT TO OVERCOME DIFFICULT MINING CONDITIONS AS A RESULT OF EXCESSIVE FAULTING. NO PRODUCTION FIGURES AVAILABLE. ; NO PRODUCTION DATA AVAILABLE FOR 1982 ; NO DETAILS OF THIS MINE'S HIGH GRADE CHROME ORE PRODUCTION IS AVAILABLE

Reserves and resources

  • Type In-situ
    Estimate year 1983
    Total resources 19000000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Chromium Cr2O3 42 wt-pct Chromium Major 1983
  • Type In-situ
    Estimate year 1975
    Total resources 15000000mt 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 305 METERS.
  • RESOURCES ARE FOR THE POTGIETERSRUS SECTOR.

Workings at the site

  • Type of workings Underground
    Overall depth 305M

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. UNUSUALLY STEEP DIP PERMITS GRAVITY FALL OF ORE DOWNDIP INTO ORE PASSES FOR RAIL-HAULAGE TO INCLINE TRANSFER POINTS. TWO INCLINES ARE IN OPERATION TO SERVE A STRIKE LENGTH OF 2440 METERS. SURFACE FACILITIES CONSIST OF HAND SORTING, SCREENS, BALL MILL, VIBRATORY TABLES AND WASHING.

Comments on development

  • MILL.CAP: 0.2 MIL. MET. T/YR ; ECON.YEAR: 1977 ; ECON.COM: THIS MINE PRODUCES SOUTH AFRICA'S HIGHEST GRADE CHROMITE AND THE BEST RECORDED CHROME IRON RATIO. ANNUAL TARGETS ARE DESIGNED TO MEET PARENT COMPANY DEMAND FOR FERROCHROME PRODUCTION (SAMANCOR) WITH THE REMAINDER EXPORTED. LOCAL MARKET AND EXPORT OUTLOOKS ARE EXCELLENT. ORE RESERVES ARE ADEQUATE FOR A LONG-LIFE FORECAST.

Reference information

Bibliographic references

  • Analytical Data

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

  • Deposit

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

  • 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

    FERROUS AND NONFERROUS MINES AND WORKS IN SOUTH AFRICA; MINERALS BUREAU; DIRECTORY NO. 3/79; 1979 .

  • Deposit

    DEYOUNG AND OTHERS, 1984, INTERNATIONAL STRATEGIC MINERALS INVENTORY SUMMARY REPORT-- CHROMITE: U.S. GEOLOGICAL SURVEY CIRCULAR 930-B, 41 P.

  • Deposit

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

  • Other Database

    ISMI

  • Production

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

  • Reserve-Resource

    DEYOUNG AND OTHERS, 1984

General comments

Subject category Comment text
Deposit MAX. THICKNESS REFERS TO AGGREGATE RECOVERABLE THICKNESS OF TWO SEAMS CURRENTLY BEING MINED. THE LOWER SEAM CONSISTS OF A LAYER 0.4 METER IN THICKNESS WHICH OVERLIES 0.25 METER OF DISSEMINATED FOOTWALL CHROMITE. THE UPPER SEAM OCCURS 70 METERS ABOVE THE LOWER AND CONSISTS OF ABOUT 0.5 METER OF RECOVERABLE ORE WITHIN 1.05 METER OF CHROMITE OF VARYING QUALITIES. DEPTH TO TOP IS RANGE FROM OUTCROP TO CURRENT VERTICAL MAX. MINING DEPTH. DEPTH TO BOTTOM (I.E. MAXIMUM DEPTH OF MINEABLE ORE) NOT KNOWN. MAX. LENGTH IS PROVED ORE STRIKE LENGTH.
Deposit INFORMATION MERGED FROM RECORD NUMBER W028906 ; W030781 ; W032266 ; W055306

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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