Mineral Resources Potential - Geothermal Resources

General characteristics of the coal deposits in Eth-
Energy Resources 207
Coal in general are assessed and classified on the basis of the
amount of fixed carbon, percentage of volatile matter, ash content
and calorific value. With favorable burial conditions (i.e. long
periods of accumulation of vegetation, thick sediment cover, depth
of burial, etc.) the deposits mature and there is a gradual increase
in the fixed carbon content and other properties. Most of the
Ethiopian coal, irrespective of their stratigraphic position and
occurrence, fhll in the category of lignite that have been deposited
under conditions lacking all these favorable factors and are,
therefore, chmcbrkd by comp&atively low maturity and
evolution (Getaneh, 1985, Wolela, 1991, 1995). Generally, they
are thin bedded, less mature and with quite high mineral content.
Consequently, most of the coal in general consists mainly of lignite
that is of high ash content (2.4% to 65%), which fulfil the
categories of soft coal, low fixed carbon (20% to 60.2%), low
calorific values (range from 900 to 6,900 callkg) and average
moisture and volatile content (fall under the categories of lignite to
I medium-high volatile bituminous coal). However, there are coal
seems having low ash contents and high calorific values (heating
value) in the acceptable range for utilization in the energy sector.
Since there are lignite with high calorific values (up to 6,400
calkg) and low ash contents (e.g. as little as 1%) these could be
blended with low calorific value and high ash-content lignite's to
reach an optimum acceptable minimum (Getmeh and Saxena,
1984). All these calls for a reassessment and =valuation of
important lignite occurrences and W e d study of their economic
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feasibility.