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Bracken Mines

Producer in South Africa with commodities Gold, Silver, PGE, Osmium, Iridium, Platinum, Ruthenium, Rhodium, Subbituminous, Sulfur-Pyrite, Uranium
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Geologic information

Identification information

Deposit ID 10078489
MRDS ID W026836
Record type Site
Current site name Bracken Mines

Geographic coordinates

Geographic coordinates: 29.10144, -26.51325 (WGS84)
Elevation 1646
Relative position 40 KILOMETERS WEST OF THE TOWN OF BETHAL; 64 KILOMETERS SOUTHEAST F THE TOWN OF SPRINGS
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Geographic areas

Country
South Africa

Commodities

Commodity Importance
Gold Primary
Silver Secondary
PGE Secondary
Osmium Secondary
Iridium Secondary
Platinum Secondary
Ruthenium Secondary
Rhodium Secondary
Subbituminous Tertiary
Sulfur-Pyrite Tertiary
Uranium Tertiary

Comments on the commodity information

  • GOLD, ONLY, IS RECOVERED AT THIS OPERATION. A LOW GRADE PRODUCER WITH LIMITED MINE LIFE. SUBBITUMINOUS COAL UNCONFORMABLY OVERLIES GOLD REEF AND MAY BE RECOVERED FOLLOWING DEPLETION OF GOLD RESERVES. SMALL QUANTITIES PT AND AG RECOVERED BUT UNIMPORTANT IN SOUTH AFRICA TERMS. PT IS AN IMPURITY IN GOLD AND IS RECOVERED AT THE RAND REFINERY AS A CONSEQUENCE OF THE PURIFICATION PROCESS.

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Sphalerite Ore
Uraninite Ore

Alteration

  • (Local) None

Analytical data

Result SEE ENTRIES UNDER PRODUCTION AND RESERVES. COAL ANALYTICAL DATA NOT AVAILABLE.

Mineral occurrence model information

Model code 193
USGS model code 29a
BC deposit profile C04
Deposit model name Quartz pebble conglomerate Au-U (BC name is Paleoplacer U-Au-PGE-Sn-Ti

Host and associated rocks

  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic)
    Rock unit name Ventersdorp System-Lava
    Rock description Ventersdorp System-Lava
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Quartzite
    Rock unit name Ecca Series, Karroo System; Shale, Sandstone & Coal;Transvaal System--Dolomite;Witwatersrand System (Upper Division)-Quartzite, Shales, Grits And Conglomerates
    Rock description Ecca Series, Karroo System; Shale, Sandstone & Coal;Transvaal System--Dolomite;Witwatersrand System (Upper Division)-Quartzite, Shales, Grits And Conglomerates
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Shale
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Conglomerate

Nearby scientific data

(1) 29.10144, -26.51325
ListMap

Geologic structures

Type Description Terms
Regional Unique Continuity Of Gold-Bearing Horizons Over Extended Area, Though Well Marked By Folding, Faulting And (Locally) Erosion And Redeposition Of Overlying Conformable Sediments.
Local Synclinal Basin Separated From Central And East Rand Occurrences Of The Witwatersrand System. Unconformable Ecca Series, Karroo System Shales, Sandstones And Coal Are Notable. Dips Variable, Faulting Severe.

Ore body information

  • General form TABULAR/BLANKET
    Dip 20 DEG. N.
    Thickness 1.2M
    Depth to bottom 1300M

Controls for ore emplacement

  • Gentle Uplift Of Continental Mass; Erosion; Peneplanation; Folding; Faulting; Volcanicity; Dike Injection And Build-Up Of Younger Sediments.

Economic information

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1951
Discoverer Capital Mining Areas, A Subsidiary Of Union Corporation Limited
Discovery method Ore-Mineral In Place
Year of first production 1962

Mining district

District name Evander Area Of The Witwatersrand Goldfields

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Bracken Mines Ltd.
  • Type Owner
    Owner Gencor (General Mining Union Corp. Ltd)

Production statistics

  • Year 1976
    Material ORE AU
    Accuracy Accurate
    Description Ap_Grade: ^0.240 Tr. Oz. Au/Met. Ton Of Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt
  • Year 1976
    Material AU
    Accuracy Accurate
    Description Ap_Grade: ^0.218 Toz. Au/Met. Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Gold Gold 0g/mt
  • Year 1977
    Material ORE
    Accuracy Accurate
    Description Ap_Grade: ^0.181 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt
  • Year 1977
    Material AU
    Accuracy Accurate
    Description Ap_Grade: ^0.214 Toz Au/Met Tons Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Gold Gold 0g/mt
  • Year 1978
    Material ORE AU
    Accuracy Accurate
    Description Ap_Grade: ^0.122 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt
  • Year 1978
    Material AU
    Accuracy Accurate
    Description Ap_Grade: ^0.115 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Gold Gold 0g/mt
  • Year 1979
    Material AU
    Accuracy Accurate
    Description Ap_Grade: ^0.113 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Gold Gold 0g/mt
  • Year 1979
    Material ORE AU
    Accuracy Accurate
    Description Ap_Grade: ^0.127 Toz Au/Mt Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major ORE Gold Gold 0g/mt
  • Year 1980
    Material ORE AU
    Accuracy Accurate
    Description Ap_Grade: ^0.112 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt
  • Year 1980
    Material AU
    Accuracy Accurate
    Description Ap_Grade: ^0.122 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Gold Gold 0g/mt
  • Year 1981
    Material ORE AU
    Accuracy Accurate
    Description Ap_Grade: ^0.105 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt
  • Year 1986
    Period 1986
    Material ORE
    Description Cp_Grade: ^0.190 T02 Au/Met Ton Ore
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt
  • Year 1986
    Period 1986
    Material ORE
    Description Cp_Grade: ^0.190 Toz Au/Met Ton Ore Milled
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Gold Gold 0g/mt

Comments on the production information

  • PRODUCTION WORKS KIMBERLY REEF WITH AU/PT RECOVERY = 70:1. ; WORKING COSTS INCREASED BY 9.3% IN 1985. ; WORKING COSTS INCREASED BY 27.7% IN 1986 ; THIS PRODUCTION DOES NOT INCLUDE 114,000 TONS MILLED FOR KINROSS MINES IN TERMS OF A TOLL AGREEMENT WHEREVY BRACKEN MILLS SURPL KINROSS TONNAGE. ; PRODUCTION COSTS INCREASED BY 11.7% IN 1984

Reserves and resources

  • Type In-situ
    Estimate year 1986
    Total resources 16,000,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 5.909 g/mt Gold Major 1986

Comments on the reserve resource information

  • CHAMBER OF MINES OF SOUTH AFRICA - 1986 ; IT IS BELIEVED TO BE UNLIKELY THAT ANY FURTHER ORE RESERVES WILL MATERIALIZE IN THE FUTURE. ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS - 1984 AND BRACKEN ANNUAL REPORT - 1984 ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS - 1985 ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS-1986

Workings at the site

  • Type of workings Underground
    Overall depth 1300M

Comments on the workings information

  • MINING METHOD: CROSSCUTS FROM THE SHAFT TO ORE HORIZON (REEF) AT 150 - METER INTERVALS; DRIVES ALONG THE STRIKE AND WINZES DOWN - DIP COMPLETE DEVELOPMENT; STOPING & BACKFILLING ("SCATTER MINING") WITH CRIB TIMBER SUPPORT AND PILLARS COMPRISE FINAL MINING PHASE. FAULTING SEVERE. OVERLYING (NEAR-SURFACE) COAL OCCURRENCE UNIQUE AND MAY THUS GIVE MINE EXTENDED LIFT AFTER DEPLETION OF GOLD RESERVES.

Comments on development

  • YEAR OF DISCOVERY DATE IS APPROXIMATE ONLY. EXPLORATION NIL. DEVELOPMENT CONFINED TO PREVIOUSLY DELINEATED ORES WITHIN LIMITED CONFINED OF PROPERTY. ; MILL.CAP: 1.0 MIL. MET. T/YR. ; ECON.YEAR: 1962 ; ECON.COM: THE FUTURE OF THE MINE DEPENDS ON THE EXPOSURE OF NEW ORE RESERVES.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS W026836

Bibliographic references

  • Deposit

    UNION CORPORATION LIMITED, ANNUAL REPORT; 1975

  • Deposit

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

  • Deposit

    MINING JOURNAL QUARTERLY REVIEW OF SOUTH AFRICAN GOLD SHARES, VOL. 19 . NO. 1 ; MAY 1975

  • Deposit

    COUSINS, 1973, PLATINOIDS IN THE WITWATERSRAND SYSTEM: JOURNAL SOUTH AFRICAN INST. MIN. AND METALL., V. 73, NO. 6, P. 3-5.

  • Deposit

    MERTIE, 1969, ECONOMIC GEOLOGY OF PLATINUM METALS: U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 630, P. 45-48.

  • Deposit

    SOUTH AFRICAN GOLD SHARES; IVOR JONES, ROY AND CO., INC., JOHANNESBURG; 197

  • Production

    ANALYSES OF WORKING RESULTS, CHAMBER OF MINES OF SOUTH AFRICA (CURRENT YEAR) ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS - 1985 ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS-1986 ; CHAMBER OF MINES OF SOUTH AFRICA - ANALYSIS OF WORKING RESULTS - 1981 ; BRACKEN MINES LIMITED ANNUAL REPORT - 1982 ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS - 1983 ; CHAMBER OF MINES ANALYSIS OF WORKING RESULTS - 1984 ; ANALYSES OF WORKING RESULTS, CHAMBER OF MINES OF SOUTH AFRICA - 1980 ; ANALYSIS OF WORKING RESULTS, CHAMBER OF MINES OF SOUTH AFRICA. JANUARY-DECEMBER 1978 ; ANALYSIS OF WORKING RESULTS, CHAMBER OF MINES OF SOUTH AFRICA. JANUARY-DECEMBER 1979 ; ANALYSIS OF WORKING RESULTS, CHAMBER OF MINES OF SOUTH AFRICA, JANUARY-DECEMBER 1977

General comments

Subject category Comment text
Deposit MAX THICKNESS REFERS TO APPROXIMATE STOPPING WIDTH OF THE KIMBERLEY REEF; THE ONLY ORE HORIZON RECOVERED AT THIS MINE. DEPTH TO BOTTOM, APPROXIMATE ONLY.
Deposit INFORMATION MERGED FROM RECORD NUMBER W028229 ; W028675 ; W028732 ; W030954 ; W032319 ; W032937 ; W033149 ; W033761 ; W044629 ; W055262
Deposit INCLUDES DATA FROM RECORD M046348 WHICH HAS BEEN DELETED FROM MRDS.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAY-1977 Sweetwood, Charles W. Department of State
Updater 01-JUL-1987 Mccarter, Lorna D Department of State
Updater 01-OCT-1978 Sweetwood, Charles W. Department of State
Updater 01-APR-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-JUN-1984 Mccarter, Lorna D. Department of State
Updater 01-JUL-1983 Mccarter, Lorna D. Department of State
Updater 01-JUN-1985 Mccarter, Lorna D Department of State
Updater 01-MAR-1986 Mccarter, Lorna D Department of State
Updater 01-JUN-1987 Mccarter, Lorna D. Department of State