Gis-Based Geostatistical Analysis of the Kenticha Tantalum Deposit and Impact of the Mining on the Environment Adola, Southern Ethiopia
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Date
2007-07
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Addis Ababa Universty
Abstract
The developing mineral industry of Ethiopia brings a considerable and irreplaceable input
fro the country’s economy. Mining at present is concentrated in the southern part of the
country within a relatively small area, where gold and tantalite ores are being mined by
open pit methods and processed. The main target of the mineral development are (i)
Adola gold field with its primary gold (Lega Dembi and Shakiso) and numerous rich
placer gold and (ii) the Kenticha province of rare metal bearing pegmatite. The present
study is concerned with the latter.
The Kenticha area in southern Ethiopia is located in the Neoproterozoic metamorphosed
volcano-sedimentary succession of greenschist to amphibolite facies metamorphism. In
the studied area, the rock sequences consist of serpentinite, talc, talc-chlorite-tremolite
schist, and granite-pegmatite units.
In order to make prognosis on the possible presence of undiscovered ore-shoots in
unexplored and under-explored parts of the Kenticha tantalite deposit, Adola Belt, GISbased
geomathematical techniques where tested. Analytical sample data generated from
thirty bore holes formed the basis for computing the studies.
The studies consisted of processing the Kenticha mine sample data- width, Ta-Nb-grade,
and accumulation from borehole data’s to discern patterns and asses the environmental
impact associated with the mining activity in the region.
The techniques adopted were frequency distribution, trend analysis, auto-grade
correlation, variogram analysis and spatial variation and land use and land cover analysis.
The frequency studies show positively skewed distributions for grade and accumulation.
Trend analysis indicates certain clear patters of value distribution. Variogram show high
‘nugget’ (random) component, anisotropy and nested structure for grade at the Kenticha
tantalite deposit.
From an integration of the results of the above different kinds of studies, certain parts of
the mine were identified for selective mining of the deposit and to further investigations
and exploration in other rare-metal-bearing pegmatite-granite districts of the rare-metal
field.
The importance of appreciation of geological factors in interpreting the geomathematical
models is stressed. The impact of the mineral industry on the environment at Kenticha area is considerable.
Therefore, the most effective least expensive and quickest means must be identified and
urgently implemented to preserve the environment or at least to minimize the undesirable
damage to it within the region.
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Keywords
Kenticha Tantalum Deposit and Impact