Geological and microstructural study of Vein graphite in Sri Lanka
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Date
1998-11-07
Authors
Balasooriya, N. W. B.
Bandaranayake, P. W. S. K.
Bandara, H. M. N.
Dahanyake, K.
Dissanayake, M. A. K. L.
Journal Title
Journal ISSN
Volume Title
Publisher
University of Peradeniya
Abstract
Graphite deposits in nature occur mainly as amorphous, flake or vein graphite.
Sri Lanka has reputation for its high quality vein graphite. Currently, there are only
two graphite mines operating at Bogala and Kahatagaha-Kolongaha areas. This study
was carried out using samples collected from Bogala and Kahatagaha mines.
The vein graphite (high crystalline) is formed in fissures, fractures or cavities
traversing igneous or metamorphic rocks such as charnockite, garnet-biotite gneiss,
marble, quatzite and calc gneiss. However marble is very rare in Kahatagaha graphite
mine. In the Kahatagaha mine, veins are usually less than a meter in thickness and
those of Bogala mines range for a few centimeters to several meters. Mineralisation is
concentrated in the zones of fractures of the overlying rocks. Alterations occur within
some minerals formed in the vicinity of the wall rock. Some veins in Bogala and
Kahatagaha mines indicated several episodes of mineralisation.
The gangue minerals observed in graphite veins of both mines are quartz,
feldspar, chalcopyrite, pyrite whereas secondary minerals are chlorite, calcite etc.
Microstructures associated with different types of graphite were examined using
JOEL JSM- T 220A Scanning Electron Microscope (SEM). The SEM studies showed
that graphite occurs as aggregates of micro fibrous and micro sheets.
Description
Keywords
Geological study , Microstructural study , Vein graphite , Physical sciences engineering and technology
Citation
Proceedings & Abstracts of the Annual Research Sessions 1998, University of Peradeniya, Peradeniya, Sri Lanka, pp.96