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

CLAY QUALITY IN THE DEPOSIT<br />
DUŠANOVAC<br />
Quality of mineral deposits involves<br />
the content of useful components and possibility<br />
of use the mineral resources [5] .<br />
Reliability of determining the quality of<br />
raw material in deposit depends on sampling<br />
method, sample weight, sample reduction<br />
on-site, preparation and processing<br />
in the laboratory, as well as the accuracy<br />
of methods of analysis.<br />
Content of useful and harmful components<br />
[3], in the clay deposit Dušanovac,<br />
were determined by chemical analyses of<br />
individual samples taken from the drill<br />
holes, drilled from the field surface. Individual<br />
samples were analyzed on Al2O3,<br />
TiO2, SiO2, Fe2O3, CaO, loss on calcination<br />
(LC) and H2O¯ (Table 1). Composite<br />
sample was obtained by material merging<br />
of ten or five consecutive, individual samples<br />
(ten meter interval). Composites of<br />
samples were analyzed on: SiO2, Al2O3,<br />
Fe2O3, CaO, MgO, S total, SO3, TiO2,<br />
K2O, Na2O, Cr2O3, loss on calcination,<br />
MnO, FeO, CO3, Mn, Fe, Cu and pH.<br />
Table 5.2. Chemical (average) contents of clay in the deposit Dušanovac from<br />
individual samples per quality classes, calculated using the<br />
program package MINEX 5.2.1.<br />
Class<br />
Al2O3<br />
Average content (%)<br />
TiO2 SiO2 Fe2O3 CaO G.ž. H2O ¯<br />
GB (yellow brown clay) 16.7 0.85 57.2 6.28 2.7 9.99 18.9<br />
GI (yellow clay) 16.5 0.86 57.5 6.01 4.16 9.59 20.5<br />
GII (gray clay) 16.7 0.87 56.5 5.94 3.64 9.51 20.4<br />
Whole deposit 16.6 0.87 56.8 5.97 3.78 9.54 20.4<br />
Physical-mechanical testing [4] were<br />
carried out on samples of clay, sandy clay<br />
and strongly clay sand. Testing of physicalmechanical<br />
characteristics of clay samples,<br />
taken by core sampling of prospecting drill<br />
holes, were carried out according to the<br />
current Standards for each type of testing<br />
for the needs of mining or as recommended<br />
by the International Society for Rock Mechanics<br />
(ISRM).<br />
The following parameters were carried<br />
out from physical properties of the clay<br />
samples [4]: humidity - W [%], specific<br />
gravity or bulk density of solids - γs<br />
[kN/m 3 ], bulk density - γz [kN/m 3 ], porosity<br />
- n [%], rate of propagation of longitudinal<br />
waves - VL [m/s], clay condensation and<br />
plasticity limits. Mechanical parameters<br />
were determined [4]: resistance parameters<br />
in direct shear, and uniaxial compressive<br />
strength. Thus, the working environment<br />
[4], in which exploitation will take place,<br />
make clay, slightly sandy clay, strong<br />
sandy clay and more heavily clay sands.<br />
Assumed angle of bench slope and final<br />
slope angle of open pit are adopted based<br />
on the following physical - mechanical<br />
characteristics of working environment:<br />
bulk density of clay d = 19.71 kN/m 3<br />
(1.971 t/m 3 ); clay cohesion C = 0.380 MPa,<br />
angle of internal support of clay, ϕ =<br />
15.33°. Based on the physical - mechanical<br />
properties of clay [4] of the deposit<br />
Dušanovac near Negotin, it is concluded<br />
that the engineering-geological characteristics<br />
are relatively favorable and that there<br />
will not be major problems in the exploitation<br />
phase.<br />
No 4,2011. 26<br />
MINING ENGINEERING