Aynak – a world-class sediment-hosted stratiform copper deposit in Afghanistan


Download 2.08 Mb.
Sana15.01.2020
Hajmi2.08 Mb.
#84900

Aynak – a world-class sediment-hosted stratiform copper deposit in Afghanistan

  • Antony Benham, Stan Coats, Fiona McEvoy
  • British Geological Survey

Structure

  • Introduction
  • Afghanistan and the BGS project
  • Mineral potential of Afghanistan
  • The Aynak copper deposit
  • Geology of the area
  • Style of mineralisation
  • Past mining/exploration activities
  • Current and future activity
  • Summary

Introduction to Afghanistan

  • Turbulent recent history
  • Since the fall of the Taliban in 2001:
  • Hamid Karzai elected
  • President
  • Peaceful elections in
  • 2004 and 2005
  • Return to stability

Mineral occurrences in Afghanistan

The Kabul Block

  • Location of the Kabul Block
  • Thought to be a terrane accreted to margins of Laurasia 250 Ma
  • Hosts numerous copper occurrences and old workings

Tectonic map of Afghanistan

  • Area shown in next slide
  • Geological map of Aynak
  • Stratigraphic column at Aynak

Mineralisation at Aynak

  • Far right: Finely laminated biotite-feldspar-quartz schist with disseminations and stringers of chalcopyrite.
  • Near right: Porphyroblastic dolomite marble with chalcopyrite.
  • Left: Bornite mineralisation within dolomite marble of the Loy Khwar Formation.
  • 1cm
  • 1cm
  • 1cm
  • Central Prospect, Aynak
  • Central Prospect, Aynak
  • Other occurrences in the Kabul Block

Past exploration at Aynak

  • Extensive and detailed exploration by Soviet geologists between1974-76 and 1978-89 including:
    • >150 boreholes
    • 70 trenches
    • 9 adits
    • Surface geological and geophysical surveying
  • Soviet “drill-indicated” resource estimate of 240 Mt @ 2.3 % Cu, however this does not conform to Western classification standards.

Current work at Aynak

  • The BGS have created a database from exploration boreholes
  • All reports relating to Aynak have been translated from Russian to English
  • A 3D model of Aynak has been created in Vulcan
  • Reports and borehole database available on request
  • The Aynak model created in Vulcan is primarily based on borehole data but also includes sections drawn by Soviet geologists
  • Left: Section through the western prospect at Aynak looking east through the steeply dipping anticline
  • Vulcan model of Aynak
  • Left: Section through the central prospect at Aynak looking west through the shallow dipping section of the Aynak anticline
  • The mineralised Loy Khwar Formation is the dark green unit 5
  • Vulcan model of Aynak
  • Vulcan model of Aynak

Possible Mineral Deposit Model

Summary

  • Main features of the Aynak deposit
  • World-class stratabound ore deposit (240 Mt at 2.3 % Cu)
  • Mineralisation hosted within dolomite marbles and calcareous-biotite schists
  • Mineralogy dominated by bornite, chalcopyrite
  • Consists of two prospects, the shallow dipping Central Prospect and the more steeply dipping Western Prospect
  • Central Prospect amenable to open-pitting
  • Other prospects close to Aynak include Darband and Jawkhar suggest Aynak is part of a larger “copper belt”

Download 2.08 Mb.

Do'stlaringiz bilan baham:




Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©fayllar.org 2023
ma'muriyatiga murojaat qiling