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Freetown Layered Basic Complex Placers.

Past Producer in Sierra Leone with commodities Platinum, Aluminum, Titanium, Metal, 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. Controls for ore emplacement
  11. Economic information about the deposit and operations
  12. Mining district
  13. Ownership information
  14. Links to other databases
  15. Bibliographic references
  16. General comments
  17. Reporter information

Geologic information

Identification information

Deposit ID 10038316
MRDS ID M045648
Record type Site
Current site name Freetown Layered Basic Complex Placers.
Alternate or previous names Colony Complex

Geographic coordinates

Geographic coordinates: -13.16527, 8.33435 (WGS84)
Relative position EXTENDS FROM FREETOWN TO YORK TO KENT TO BANANA ISLANDS.

Site location context

Political divisions (FIPS codes)

Sierra Leone(country)

Geographic areas

Country
Sierra Leone

Comments on the location information

  • BIG WATER, GINDA WATER, GOMA WATER, AIAKO WATER, BABADORI STREAM PLACERS ARE ALL DEPOSITS RELATED TO THIS COMPLEX

Commodities

Commodity Importance
Platinum Critical Primary
Aluminum Critical Tertiary
Titanium, Metal Critical Tertiary
Iron Tertiary

Comments on the commodity information

  • NUGGETS BETWEEN 0.25 AND 0.52 OZ. COMMON; ONE 1.25 OZ. FOUND - ILMENITE CONCENTRATES SHOW 0.60 TOZ/TON, SLIMES GAVE 1.5 OZ PER TON.

Materials information

Materials Type of material
Ilmenite Ore
Magnetite Ore

Analytical data

Result PT=93.14, IR=1.01, OS+IR= 2.82, RH= 1.29, PD= 1.74 (MERTIE 1969) PLATINUM CONCENTRATE RECALCULATED. ROCKS HIGHEST CONC REPORTED 0.0125 OZ PER TON.

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock
    Stratigraphic age (youngest) Late Triassic
  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro
  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Gabbro > Troctolite
  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Anorthosite
  • Host or associated Host
    Rock type Unconsolidated Deposit > Sand and Gravel

Nearby scientific data

(1) -13.16527, 8.33435
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Stratiform Complex

Controls for ore emplacement

  • Sources Believed To Be Anorthosites, But Nj Page Suspects Magnetite - Ilmenite Horizons.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Significant No
Discovery year 1926
Discoverer N.R. Junner.
Year of first production 1928

Mining district

District name Freetown Layered Basic Complex.

Ownership information

  • Type Owner
    Owner Last Production Recorded (-
    Last year 1957

Comments on the production information

  • PRODUCTION FROM GOMMA, GLINDA, AIAKO, AND BIGWATER PLACERS.

Comments on the reserve resource information

  • MERTIE (1969) SAYS PT METAL GRAINS ARE WIDELY DISSEMINATED AND NOT CONCENTRATED IN ROCK.; BUT LONG PERIOD OF WEATHERING RESPONSIBLE FOR PLACERS, SOME ONE SHOULD ANALYZE SOME ROCKS.

Comments on the workings information

  • SEE INDIVIDUAL PLACER RECORDS.

Comments on development

  • ECON.COM: MINING IMPRACTICABLE DURING WET SEASON, DONE OCT. THROUGH MAY.

Reference information

Bibliographic references

  • Deposit

    WELLS, 1962, GEOL. SURV. DEPT. SIERRA LEONE SHORT PAPER, NO. 9, 115 P.

  • Deposit

    POLLETT, J.D., 1951, COLON. GEOL. MIN. RESOURCES, V. 2, NO. 1, P. 3-28

  • Deposit

    POLLETT, 1952, 1931; JUNNER, 1930; JUNNER AND HARWOOD, 1930; WELLS AND BAKER, 1956; BAKER, 1961; DIXEY, 1922

  • Deposit

    BRIDEN, HENTHORN, REX, 1971, EAR. PLAT. SCI. LETTERS 12 P. 385-391.

  • Deposit

    1920 DIREXPL GEOLOGICAL SURVEY OF SIERRA LEONE.

  • Deposit

    1930 GEOLMAP GEOLOGICAL SURVEY OF SIERRA LEONE.

  • Deposit

    1969 ART FORD HAS ROCKS AND THIN SECTIONS.

  • Production

    MERTIE (1969)

General comments

Subject category Comment text
Deposit FREETOWN COMPLEX CONSISTS OF FIVE ZONES: (1) MARGINAL ZONE: GABBROS, TROCTOLITES; HORNBLENDE GABBROS AND NORITES; GRANULITISED GABBROS, DOLERITES AND METADOLERITES, AMPHIBOLITES AND HBN SCHISTS OF COUNTRY ROCK - LIES ON EAST PART NOT EXPOSED AT SURFACE. (2) ZONE 1: TROCTOLITE, DUNITE, TROCTOLITIC GABBRO ANORTHOSITIC GABBRO, LEUCO GABBRO, THIN ANORTHOSTIE (3) ZONE 2: THICK TROCTOLITE, GABBRO, OLIVINE GABBRO, 160-580 FEET ANORTHOSITE. (4) ZONE 3: THIN TROCTOLITE, OLIVINE GABBRO, TROCTOLITIC GABBROS, LEUCOGABBRO, 2500 FEET ANORTHOSITE, (5) ZONE 4: TROCTOLITE, OLIVINE GABBROS, RHYTHMIC GABBRO UNITS, GABBRO PEGMATITE. ILMENITE - MAGNETITE LAYERS IN ZONES 2,3,4. - TOTAL THICKNESS OF COMPLEX ABOUT 20,500 FEET; ROCKS DESCRIBED CUMULATES WITH ASSEMBLAGES: (1) OLIVINE, OLIVINE + PLAGIO, PLAGIO + ORTHO PYROXENE, PLAGIO + OPX + CPX (2) OLIVINE, OL + PLAGIO, OL + PLAGIO + CPX, (?) PLAGIO + CPX + OPX; SOME CUMULUS PIGEONITE, TITANIFEROUS MAGNETITE ALSO CUMULATE. COMPLEX OUTCROPS FOR 170 SQMILES
Deposit OR 29X9 MILES - MOST PT OCCURRENCES WEST OF MAIN MT RANGE, WEST OF ZONE 3. COMPLEX CUT BY DOLERITE DIKES AND MORE ACID ROCKS, EACH ZONE MARKED BY TRAINS OF INCLUSIONS AND CONTAMINATED ROCKS. B

Reporter information

Type Date Name Affiliation Comment
Reporter 01-APR-1975 Page, Norman J. U.S. Geological Survey

Beyond USGS

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

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