Mineral Resources Potential - Geothermal Resources

Mttallic Minerals 67
Genetically, the gold placers of the Adola area fall in
three groups.
(i) residual-eluvial (slope placers) at sites of disintegration
primary source, (ii) eluvial-alluvial lacers formed in small valleys
and fans, due to intermittent stre !m activity, and (iii) alluvial
placers formed in the valley floor and on river ' terraces.
Commercially, the potential of the area is linked with the alluvial
placers containing the bulk of the estimated reserves. Residual-
eluvial and proluvial placers are targets for hand mining
operations. The major part of known placers is shallow-lying with
overburden being as thick as 20 m (e.g., Kajimiti).
Based on the mode of occurrence and geology of placers of
the area, the following observations can be madel-the low-order
valleys are rather monotonous in geomotphic aspect along their
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entire length. The Iarger valleys (such as Bore, Kajimiti, ,-, + .-.
Bedakessa, Awata, and Mormora) have contrasting morphologies
at different sections due to locd control by undetlying geology, . .
neotectonics and faults. LOW-or& valleys have no terraces.
Terraces of high-order valleys as a rule have little or no surface
expression in topography. In most cases the terraces are buried
under slope waste.
All placer gold occurrences are discontinuous; they form
isolated grounds and pay-streaks. Gold is concentrated as nests and
as combination of nests and pay streaks. Nest-like concentrations
most frequently occy against distributed gold.
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Tn conclusion, the regional distribution of placer deposits
and occurrences in the area is characterized by distinct spatial
association with both the Megado and Kenticha primary gold belts.
This emphasises the intimate spatial association of the areas of
placer formations with the primary gold fields. The majority of the
placers are localised in the areas of enhanced erosive
transformation of the relief. Structurally the Adola area consists of
numerous, variously uplifted blocks of the crystalline basement.