A New Occurrence of (Gold-Bearing) Graphite in the Assosa Region, Benishangul-Gumuz State, W Ethiopia

Liam A Bullock, Owen J Morgan

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Abstract

The Assosa region of western Ethiopia hosts newly discovered and potentially highly economic graphite-bearing schist units. Due to its unique physical and chemical properties, graphite is quickly becoming an increasingly important economic resource. Graphite occurs over much of the area, and is hosted predominantly by quartz-graphitic schist, quartz-feldspar-mica schist and quartzite. The quartz-graphitic schist covers an area of 37 km2, forming steep valleys and ridges across a 190 km long belt. Graphite is texturally-variable within and across units. Crystal habit varies from highly crystalline to irregular flakes. Flake sizes range from amorphous and crystalline small flake to coarse large flake (> 150 μm), with beneficiation of ~ 70% and yield potential of > 95% (froth flotation methods). The license area is already a well-known gold-hosting area, and potentially economic gold deposits occur within the graphite-bearing units. Overall, the site shows excellent geochemical indicators, field observations and historical accounts of high gold content. It is suggested that textural variations may be the product of (1) early in-situ formation during (early- to late-Proterozoic) prograde metamorphism and (2) later vein-type mineralization during retrograde metamorphism. The discovery of graphite in western Ethiopia is the first documented and preliminary studies suggest a high economic potential for the deposits.
Original languageEnglish
Pages (from-to)417-435
Number of pages19
JournalJournal of Earth Science and Engineering
Volume5
Issue number7
DOIs
Publication statusPublished - Jul 2015

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graphite
gold
schist
quartz
economics
prograde metamorphism
retrograde metamorphism
mica
range size
feldspar
chemical property
Proterozoic
physical property
crystal
mineralization
valley
resource

Keywords

  • graphite
  • gold
  • Ethiopia
  • metamorphism
  • X-ray fluorescence
  • X-Ray diffraction

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A New Occurrence of (Gold-Bearing) Graphite in the Assosa Region, Benishangul-Gumuz State, W Ethiopia. / Bullock, Liam A; Morgan, Owen J.

In: Journal of Earth Science and Engineering, Vol. 5, No. 7, 07.2015, p. 417-435.

Research output: Contribution to journalArticle

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note = "Acknowledgements Fieldwork and mapping was carried out by GP Resource Mining PLC in partnership with Tactical Environmental Response Ltd (TER). TER was responsible for the geochemical analysis, with the exception of XRD. The authors wish to greatly thank David Evans (XRD), Peter Greatbatch and David Wilde (thin sectioning) of Keele University. The authors also wish to thank the anonymous reviewers for manuscript feedback and comments.",
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