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

Fig. 1. Graphical presentation the quantities of ore and waste and value of open pits for<br />
limit content of 0.15% Cu in the ore<br />
Designed open pit mining of the South<br />
Mining District will be realized by the<br />
“best case” variant or so-called pushback<br />
excavation.<br />
Limit open pit for the aforementioned<br />
initial techno-economic parameters is the<br />
open pit with a factor of income equal to<br />
one, or the open pit No.36. Since the open<br />
pits from No.34 to No.38 are positive,<br />
according to the “best“ variant of excavation,<br />
with the existing data taken into optimization,<br />
the open pit No.33, with recovery<br />
factor of 0.94, was selected for<br />
construction the open pit that includes the<br />
balance reserves.<br />
This open pit was selected due to the<br />
spatial constraints, on one hand, and the<br />
other hand, due to the security, regarding to<br />
a possibility that the investments are not<br />
fully defined. The assumed profit, obtained<br />
in the software package Whittle for the<br />
variant of open pit No.33, would provide<br />
the additional investments, while the economic<br />
value of deposit remains positive.<br />
Constructed final contour of open pit in<br />
the software package Gemcom has 41<br />
benches. The highest bench is E+590, and<br />
the lowest bench is E-10. The designed<br />
pushback assumed excavation with main<br />
parameters given in Table 2. View of the<br />
final open pit contour is shown in Figure 2.<br />
Table 2. Balance reserves in the copper<br />
deposit South Mining District<br />
Majdanpek in a contour of limit<br />
content 0.15% Cu<br />
Material Qunatity<br />
Ore (t) 246 947 462<br />
Waste (t) 596 081 443<br />
Excavation (t) 843 028 905<br />
Overburden ratio (t/t) 2.414<br />
Cu (%) 0.357<br />
Ag (g/t) 1.469<br />
Au (g/t) 0.199<br />
No 4, 2011. 90<br />
MINING ENGINEERING