Rudarski radovi br 4 2011 - Institut za rudarstvo i metalurgiju Bor

Fig. 4. Field in the domain of clay deposit Dušanovac (left) and the view from the<br />
Hydroelectric Plant Iron Gate 2 (right)<br />
The clay deposit [3,5] was explored by<br />
trenches (totally 4 trenche, dimensions<br />
2×2.5×1 m) and geological prospecting<br />
drill holes. According to the vertical profile<br />
of all trenches, the ground surface to<br />
the depth of soil from 0.6 to 0.7 m was<br />
observed, and below that the yellow<br />
brown sandy clay with the appearance of<br />
carbonate. One sample was taken frfrom<br />
each trench for chemical testing.<br />
Sampling intervals [3] of cores from<br />
prospecting drill holes were 1 or 2 m. Total<br />
of 370 individual samples were taken,<br />
out of which 41 composite samples were<br />
formed. Composite samples were specially<br />
formed for the yellow clay class,<br />
specially for the gray class of clay quality.<br />
Studying the pillars of drill holes [3], it<br />
was observed that macroscopically,according<br />
to the color of clay<br />
deposit, four layers can be broken<br />
down:<br />
► Brown clay lies immediately below<br />
the humus cover, which has the average<br />
thickness of about 0.7 m.<br />
Clay is poor to more sandy, the average<br />
thickness of this layer is<br />
about 1.5 m;<br />
► Yellow clay lies below brown clay,<br />
average thickness of about 13.0 m.<br />
This clay is greasy, very plastic and<br />
slightly sandy with occasional occurrence<br />
of FeO and MnO coating.<br />
A layer of yellow clay occurs<br />
throughout the deposit;<br />
► Brown-gray clay is spatially positioned<br />
below the yellow and above the<br />
gray clay above. A layer of browngray<br />
clay represents a zone of mixing<br />
of yellow and gray clay and it is<br />
very sandy, and the average thickness<br />
of this layer is about 6.0 m.<br />
► Gray clay is the average thickness<br />
of about 35.5 m and it is located<br />
below the brown-gray clay. It is<br />
very sandy, and thin interlayers of<br />
a strong clay sand are very rarely<br />
observed in this thin layer. The fossil<br />
remains of shells also occur in<br />
this layer. A layer of gray clay with<br />
increasing of a depth gradually becomes<br />
very clay sand. A layer of<br />
gray clay was drilled by all drill<br />
holes.<br />
Physical-mechanical testing [4], grainsize<br />
distribution testing [6,7], laboratory<br />
technology and chemical testing were carried<br />
out from laboratory testing on taken<br />
samples. Technological tests in semi-industrial<br />
and industrial scale, were not done.<br />
No 4,2011. 25<br />
MINING ENGINEERING