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Black Rock Mine

Producer in Eastern Cape, South Africa with commodities Manganese, Iron
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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. Host and associated rocks
  8. Nearby scientific data
  9. Geologic structures
  10. Ore body information
  11. Controls for ore emplacement
  12. Economic information about the deposit and operations
  13. Mining district
  14. Land status
  15. Ownership information
  16. Production statistics
  17. Workings at the site
  18. Links to other databases
  19. Bibliographic references
  20. General comments
  21. Reporter information

Geologic information

Identification information

Deposit ID 10079221
MRDS ID W028269
Record type Site
Current site name Black Rock Mine
Alternate or previous names Devon & Adams Mine
Related records 10207613, 10207629, 10207741, 10280817

Geographic coordinates

Geographic coordinates: 25.221, -29.04763 (WGS84)
Elevation 1100
Relative position BLACK ROCK MINE: 81 KILOMETERS NORTHWEST OF KURUMAN; DEVON MINE: 56 KILOMETERS NORTHWEST OF KURUMAN; ADAMS MINE: 47 KILOMETERS NORTHWEST OF KURUMAN, No latitude-longitude reported. Given lat-lon is for centroid of first order political subdivision boundary.

Site location context

Political divisions (FIPS codes)

Eastern Cape(province)

South Africa(country)

Africa(continent)

Land(continent)

Geographic areas

Country State
South Africa Eastern Cape

Comments on the location information

  • BLACK ROCK MINE: LATITUDE 27 DEGREES 08 MINUTES S, LONGITUDE 22 DEGREES 50 MINUTES E; DEVON MINE: LATITUDE 27 DEGREES 15 MINUTES S, LONGITUDE 23 DEGREES 00 MINUTES E; ADAMS MINE: LATITUDE 27 DEGREES 21 MINUTES S, LONGITUDE 23 DEGREES 02 MINUTES E.

Commodities

Commodity Importance
Manganese Critical Primary
Iron Secondary

Comments on the commodity information

  • COMBINED METAL CONTENT RANGES BETWEEN 50 - 68 PERCENT. MANGANESE TO IRON RATIO: 2.4:1.0 TO 4.0:1.0 . LOW PHOSPHOROUS AND SULFUR CONTENTS COMBINE TO MAKE THE ORE AN EXCELLENT BLEND MATERIAL WITH MANGANESE FROM OTHER SOURCES.

Materials information

Materials Type of material
Bixbyite Ore
Clay Gangue

Analytical data

Result SEE PRODUCTION ENTRIES.

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic)
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic)

Nearby scientific data

(1) 25.221, -29.04763
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Low Intensity Anticlines And Synclines Regionally. Faulting Intermittent And Of Limited Magnitude.
Type of structure Local
Structure description The Ore-Bearing Structure Is A North-Trending Asymmetrical Anticline Planed Off By Erosion. Dips Are Moderately Variable On The Western Limb ( 20 - 25 Degrees West ) And Broken By Faulting, And Erratic, On The Eastern Limb.

Ore body information

  • General form TABULAR/BLANKET
    Strike N 20 DEG. W
    Dip 20 - 25 DEG. W.
    Thickness 12M
    Depth to top 183M
    Depth to bottom 195M

Controls for ore emplacement

  • Gentle Uplift Of Continental Mass; Minor Folding And Faulting; Erosion; Man Ganiferous Solutions Circulated Through Tectonically Disturbed Banded Ironstone Syngenetically) To Give Rise To Metasomatic Replacement Of The Country Rock With Manganese Along Favorable Layers.

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Large
Significant No
Discovery year 1941
Discoverer L. G. Boardman
Year of first production 1955

Mining district

District name Kalahari Field

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner The Associated Manganese Mines Of South Africa, Ltd.
  • Type Owner
    Owner Anglo Transvaal Consolidated Investment Co., Ltd.

Production statistics

  • Year 1977
    Material ORE MN
    Accuracy Estimate
    Description Ap_Grade: ^46 % Mn
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Manganese Manganese 46wt-pct
  • Year 1978
    Material ORE MN
    Accuracy Estimate
    Description Ap_Grade: ^46 % Mn
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Manganese Manganese 46wt-pct
  • Year 1979
    Material ORE MN
    Accuracy Estimate
    Description Ap_Grade: ^ 15 % Fe (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Iron Iron 15wt-pct
  • Year 1980
    Material ORE MN
    Accuracy Estimate
    Description Ap_Grade: ^ 15 % Fe (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Iron Iron 15wt-pct
  • Year 1981
    Material ORE MN
    Accuracy Estimate
    Description Ap_Grade: ^46 % Mn
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Manganese Manganese 46wt-pct
  • Year 1983
    Period 1965-1983
    Material ORE MN
    Description Cp_Grade: ^46 % Mn
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Manganese Manganese 46wt-pct
  • Year 1983
    Material ORE MN
    Accuracy Estimate
    Description Ap_Grade: ^ 15 % Fe (Approximately)
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Iron Iron 15wt-pct

Comments on the production information

  • OPERATOR REPORTS ONLY THE COMBINED PRODUCTION FROM ITS 8 MINES IN 2 FIELDS (MN ORE 1969-1980=17,997,000 MET TONS). THIS RECORD DEALS ONLY WITH THE KALAHARI FIELD (BLACK ROCK,DEVON,& ADAMS MINES) IN WHICH PRODUCTION DATA ARE ESTIMATED VALUES, CALCULATED FROM INDICATED OUTPUT PERCENTAGES BY FIELD. CUMULATIVE ANALYSES NOT AVAILABLE & GRADE ESTIMATES ARE FROM MINERAL RESOURCES OF THE REPUBLIC OF SOUTH AFRICA,5TH ED.,HNDBOOK 7,DEPT OF MINERALS & ENERGY AFFAIRS,GEOL SURVEY,1976. FOR DATA ON POSTMASBURG FIELD SEE RECORD NO W028270. ; THE ASSOCIATED MANGANESE MINES OF SOUTH AFRICA, LIMITED, ANNUALLY REPORTS ONLY THE TOTAL PRODUCTION OF ITS OPERATING MINES - MOKANING, BISHOP, GLOUCESTER, PALING AND BEESHOEK (REPORTED IN PRIMARY RECORD NO. W028270 AND SUBSEQUENT ANNUAL UPDATE RECORDS) AND BLACK ROCK, DEVON AND ADAMS MINES (REPORTED IN PRIMARY RECORD NO. W028269 AND IN THIS RECORD). ALL-COMPANY PRODUCTION DURING 1980 IS REPORTED TO HAVE BEEN 1551.000 TONS OF MANGANESE ORE. THE COMBINED
  • PRODUCTION OF THE BLACK ROCK, DEVON AND ADAMS MINES (AS PART OF THE FIRM'S TOTAL MANGANESE OUTPUT) IS ESTIMATED ABOVE, AS A CALCULATION FROM INDICATED OUTPUT PERCENTAGES BY FIELD. ANNUAL ANALYSES ARE NOT AVAILABLE. GRADE ESTIMATES ARE FROM MINERAL RESOURCES OF THE REPUBLIC OF SOUTH AFRICA, FIFTH EDITION, HANDBOOK 7, DEPARTMENT OF MINERALS AND ENERGY AFFAIRS, GEOLOGICAL SURVEY, 1976. ; ASSOCIATED MANGANESE MINES REPORT ONLY A TOTAL PRODUCTION FOR THEIR MINES - 1,382,000 METRIC TONS AND PRODUCTION FOR THE MINES IN THIS RECORD HAVE BEEN CALCULATED ON THE BASIS OF INDUSTRY INFORMATION RECEIVED. ; THE ASSOCIATED MANGANESE MINES OF SOUTH AFRICA, LIMITED, ANNUALLY REPORTS ONLY THE TOTAL PRODUCTION OF ITS OPERATING MINES -- MOKANING, BISHOP, GLOUCESTER, PALING & BEESHOEK MINES (REPORTED IN PRIMARY RECORD NO W028270 AND SUBSEQUENT ANNUAL UPDATE RECORDS) AND BLACK ROCK, DEVON & ADAMS MINES (REPORTED IN PRIMARY RECORD NO. W028269, AND IN THIS RECORD). ALL-COMPANY PRODUCTION DURING 1979 IS
  • REPORTED TO HAVE BEEN 1,741,000 TONS OF MANGANESE ORE. THE COMBINED PRODUCTION OF THE BLACK ROCK, DEVON & ADAMS MINES (AS PART OF THE FIRM'S TOTAL MANGANESE OUTPUT) IS ESTIMATED ABOVE, AS A CALCULATION FROM INDICATED OUTPUT PERCENTAGES BY FIELD. ANNUAL ANALYSES ARE NOT AVAILABLE. GRADE ESTIMATES ARE FROM MINERAL RESOURCES OF THE REPUBLIC OF SOUTH AFRICA, FIFTH EDITION, HANDBOOK 7, DEPARTMENT OF MINES, GEOLOGICAL SURVEY; 1976. ; THE ASSOCIATED MANGANESE MINES OF SOUTH AFRICA, LIMITED, ANNUALLY REPORTS ONLY THE TOTAL PRODUCTION OF ITS OPERATING MINES -- MOKANING, BISHOP, GLOUCESTER, PALING & BEESHOEK MINES (REPORTED IN PRIMARY RECORD NO W028270 AND SUBSEQUENT ANNUAL UPDATE RECORDS) AND BLACK ROCK, DEVON & ADAMS MINES (REPORTED IN PRIMARY RECORD NO. W028269, AND IN THIS RECORD). ALL-COMPANY PRODUCTION DURING 1978 IS REPORTED TO HAVE BEEN 1,758,000 TONS OF MANGANESE ORE. THE COMBINED PRODUCTION OF THE BLACK ROCK, DEVON & ADAMS MINES (AS PART OF THE FIRM'S TOTAL MANGANESE OUTPUT) IS
  • ESTIMATED ABOVE, AS A CALCULATION FROM INDICATED OUTPUT PERCENTAGES BY FIELD. ANNUAL ANALYSES ARE NOT AVAILABLE. GRADE ESTIMATES ARE FROM MINERAL RESOURCES OF THE REPUBLIC OF SOUTH AFRICA, FIFTH EDITION, HANDBOOK 7, DEPARTMENT OF MINES, GEOLOGICAL SURVEY; 1976.

Workings at the site

  • Type of workings Surface/Underground
    Overall depth 183M

Comments on the workings information

  • MECHANIZED ROOM AND PILLAR METHOD OF MINING AT BLACK ROCK. POWER SHOVEL AND TRUCK OPEN PIT OPERATION AT ADAMS.

Comments on development

  • INITIAL DISCOVERY ( BOARDMAN, 1941 ) WAS FROM IDENTIFICATION OF ORE MINERALS IN PLACE IN PROMINENT OUTCROP. SUBSEQUENT WORK HAS BEEN BY GEOPHYSICAL METHODS, DRILLING AND UNDERGROUND DEVELOPMENT. ; MILL.CAP: 1.5 MIL. MET. T/YR. ; ECON.YEAR: 1974 ; ECON.COM: ONE UNDERGROUND (BLACK ROCK MINE) AND ONE OPEN PIT OPERATION (ADAMS MINE) COMPRISE THIS COMPLEX. A THIRD OPEN PIT, (DEVON MINE) IS CURRENTLY IDLE. TWO UNUSUALLY UNIFORM OREBODIES, FLAT DIPS AND LOW COST MECHANIZED ROOM AND PILLAR MINING METHODS COMBINE TO MAKE OPERATION VIABLE. SALEABILITY OF THE ORE IS EXCELLENT--FOR THE FERROALLOYS INDUSTRY LOCALLY (AS DIRECT FEED ORE) AND FOR EXPORT (AS BLEND ORE).

Reference information

Bibliographic references

  • Deposit

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

  • Deposit

    MINERAL RESOURCES OF SOUTH-CENTRAL AFRICA; PELLETIER, R. A.; 1964

  • Deposit

    THE MANGANESE DEPOSITS OF THE UNION OF SOUTH AFRICA, HANDBOOK 2 , DEPARTMENT OF MINES, GEOLOGICAL SURVEY; 1960

  • Production

    ANNUAL RPTS OF ASSOC MANGANESE MINES OF SOUTH AFRICA LTD. ; ASSOCIATED MANGANESE COMPANY OFFICIALS ; ASSOCIATED MANGANESE MINES ANNUAL REPORT - 1981

General comments

Subject category Comment text
Deposit MAX. THICKNESS REFERS TO TWO PERSISTENT OREBODIES, EACH APPROXIMATELY 6 METERS IN THICKNESS. BOTH ARE DEVELOPED FOR MINING. THIN-BEDDED IRONSTONE HORIZON SEPARATES THE TWO. DEPTH TO TOP REFERS TO DEPTH OF UPPER OREBODY AT THE BLACK ROCK MINE'S SINGLE VERTICAL SHAFT. DIP IS MODERATELY VARIABLE ON WESTERN LIMB OF NORTH-TRENDING ASYMMETRICAL ANTICLINE AND BROKEN BY FAULTING, AND ERRATIC, ON THE EASTERN LIMB.
Deposit INFORMATION MERGED FROM RECORD NUMBER W028852 ; W028853 ; W030796 ; W032374 ; W033591

Reporter information

Type Date Name Affiliation Comment
Reporter 01-NOV-1978 Sweetwood, Charles W. Department of State
Updater 01-AUG-1984 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-AUG-1982 Mccarter, Lorna D. Department of State
Updater 01-AUG-1984 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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