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El Asiento Mine

Producer in Potosi, Bolivia with commodities Tin, Silver, Gold, Lead, Zinc, Copper
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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. Mineral occurrence model information
  9. Host and associated rocks
  10. Nearby scientific data
  11. Geologic structures
  12. Ore body information
  13. Economic information about the deposit and operations
  14. Ownership information
  15. Reserves and resources
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10006312
MRDS ID BL20307
Record type Site
Current site name El Asiento Mine

Geographic coordinates

Geographic coordinates: -66.55363, -20.01287 (WGS84)
Elevation 4300
Relative position 5.5 KM N20W OF TOMAVE

Site location context

Political divisions (FIPS codes)

Potosi(province)

Bolivia(country)

South America(continent)

Land(continent)

Geographic areas

Country State
Bolivia Potosi
Bolivia Potosi

Commodities

Commodity Importance
Tin Critical Primary
Silver Primary
Gold Primary
Lead Tertiary
Zinc Critical Tertiary
Copper Tertiary

Materials information

Materials Type of material
Cassiterite Ore
Galena Ore
Gold Ore
Proustite Ore
Sphalerite Ore
Tetrahedrite Ore
Alunite Gangue
Barite Gangue
Jarosite Gangue
Pyrite Gangue
Quartz Gangue

Alteration

  • (Local) Alteration Zone 3 Km Long And 1.7 Km Wide Oriented Ne-Sw With Central Zones Of Sericitization And Disseminated Pyrite, Zoning Outward Through Argillic To Propylitic. Silicification Is Limited To Vein Selvages, Silurian Sediments, And Zones Of Argillic Alteration, Particularly In The Upper Part Of The Volcanic Dome. The Diatreme Is Stongly Propylitized.

Mineral occurrence model information

Model code 77
USGS model code 20b
Deposit model name Sn-polymetallic vein

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Quartzite
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Siltstone
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Tuff
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Quartz Latite
    Rock unit name Llallagua;Cuzco
    Rock description Llallagua;Cuzco

Nearby scientific data

(1) -66.55363, -20.01287
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description N30-40w Syncline
Type of structure Local
Structure description Diatreme (Vent For Tuff), Quartz Latite Volcanic Dome Intruding Margin Of Diatreme

Ore body information

  • Strike N 10-30 W
    Dip 80 NE
    Length 3000M
    Width 1700M

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Significant No
Discoverer Spanish Colonists
Production years 1873-1911, 1934-1936

Ownership information

  • Type Operator
    Owner Cooperativa Minera Pulacayo
  • Type Owner
    Owner Corporacion Minera De Bolivia (Comibol)

Reserves and resources

  • Type In-situ
    Estimate year 1990
    Total resources 6000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 233 g/mt Silver Major 1990
  • Type In-situ
    Estimate year 1990
    Total resources 15000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 105 g/mt Silver Major 1990
  • Type In-situ
    Estimate year 1990
    Total resources 9000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Silver Ag 59 g/mt Silver Major 1990

Comments on the reserve resource information

  • (1-3) GEOLOGIC POTENTIAL, AU GRADES RANGE FROM 0.1 TO 36 G/MT; (1) UNDERGROUND VEIN SULFIDE; (2) OPEN PIT OXIDE; (3) OPEN PIT SULFIDE

Comments on the workings information

  • OPEN CUTS, SHAFTS, CROSSCUTS, DRIFTS. COLONIAL WORKINGS CONCENTRATED ON QUARTZ-JAROSITE VEINLETS IN SILURIAN SEDIMENTS. WORKINGS IN THE ZONA PRINCIPAL INCLUDE NUMEROUS PROSPECTS ON SMALL VEINLETS AND THE ROMERO AND PALMERO CROSSCUT ADITS ON THE BARRERO VEIN, WORKED DOWN TO WATER TABLE AT 280 M DEPTH, WHICH WERE LARGELY DEVELOPED IN POST-COLONIAL TIMES.

Comments on development

  • WORKED IN A SMALL WAY BY SPANISH COLONISTS. MAIN PERIOD OF DEVELOPMENT IN 1880'S WHEN AT LEAST TWO SMALL SMELTERS OPERATED. PROPERTY ACQUIRED 1921 BY HOCHSCHILD CO. AND OPERATED FOR AU-AG-SN FROM 1934 TO 1936. PROPERTY NATIONALIZED IN 1952 AND PASSED TO COMIBOL. SINCE THEN THE MINE HAS BEEN OPERATED INTERMITTENTLY BY COOPERATIVES UNDER LEASE FROM COMIBOL. PROPERTY WAS SYSTEMATICALLY EXPLORED AND DRILLED FROM THE BOTTOM LEVEL OF THE VETA BARRERO WORKINGS BY PROSPECTION LTD., A CANADIAN FIRM, FROM 1957 TO 1964. ; ECON.COM: SMALL SMELTING FURNACES BUILT IN 1886 AND 1888.

Reference information

Bibliographic references

  • Deposit

    UNDP, 1989, EL ASIENTO: YACIMIENTOS DE METALES PRECIOSOS DE BAJA LEY Y GRAN VOLUMEN: PROYECTO BOL/87/12 FOLLETO TECNICO PROMOCIONAL, 14 P.

  • Deposit

    ESPINOZA, O.A., 1989, INFORME GEOLOGICO MINERO DEL ASIENTO: MINTEC, INFORME INTERNO.

  • Deposit

    GUSTAVSON ASSOC., 1992, COMPENDIUM OF THE ECONOMIC GEOLOGY OF BOLIVIA

  • Deposit

    PINTO V., J., 1988, MODELO CONCEPTUAL Y EVALUACION DE METALES PRECIOSOS EL ASIENTO, POTOSI, BOLIVIA: UNDP PROYECTO BOL/87/012 INFORME INTERNO, 30 P.

  • Deposit

    AHLFELD, F., AND SCHNEIDER-SCHERBINA, A., 1964, LOS YACIMIENTOS MINERALES Y DE HIDROCARBUROS DE BOLIVIA: DEPARTAMENTO NACIONAL DE GEOLOGIA BOLETIN 5, P. 297.

  • Deposit

    UNITED NATIONS DEVELOPMENT PROGRAM STUDY 1988-1989 (PINTO, 1988; UNDP, 1989

  • Other Database

    CIMRI

General comments

Subject category Comment text
Deposit ZONES OF ALTERATION AND MINERALIZATION IN VOLCANIC ROCKS INCLUDING VEINS, LARGEST KNOWN AS VETA BARRERO STRIKES N10-30W, 0.3 M WIDE, AND VEINLETS, STRIKING NE AND SOMETIMES NW, A FEW MM TO 20 CM WIDE, CONSISTING OF QUARTZ, AURIFEROUS PYRITE, SPHALERITE, ARSENOPYRITE, TETRAHEDRITE, CASSITERITE, BARITE, AND GALENA. WALL ROCKS ARE SERICITIZED AND MINERALIZED WITH DISSEMINATED PYRITE (10 VOL %) LOCALLY WITH INCLUSIONS OF NATIVE GOLD AND PROUSTITE. THE TWO MAIN ZONES OF STOCKWORK MINERALIZATION ARE ZONA PRINCIPAL, LOCATED IN THE VOLCANIC DOME, 950 M LONG AND 130 M WIDE, AND ZONA CERILLOS IN TUFF AND SANDSTONE. MINERALIZATION IN SILICIFIED SILURIAN SEDIMENTS CONSISTS OF STOCKWORK VEINLETS OF QUARTZ AND JAROSITE. MINERALIZATION IS ZONED VERTICALLY FROM UPPER BARITE-CHALCEDONIC QUARTZ-COLLOIDAL CASSITERITE, INTERMEDIATE PYRITE-SPHALERITE-TETRAHEDRITE, AND DEEP PYRRHOTITE-CHALCOPYRITE. VALUES IN SN, AND AG DECREASE WITH DEPTH. HIGHEST GOLD VALUES WERE FOUND IN THE INTERMEDIATE ZONE. SURFACE
Deposit LEACHING AND OXIDATION IS LIMITED TO 10 TO 20 M DEPTH.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAR-1991 Guerra, Edwin Servicio Geologic de Bolivia
Updater 01-NOV-1993 Long, Keith R. U.S. Geological Survey

Beyond USGS

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

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