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

Table 1. Summary of initial techno-economic parameters for deposit optimization<br />
Parameter<br />
Base metal prices<br />
Unit Value<br />
� copper USD/t 6 500.00<br />
� gold USD/kg 35 000.00<br />
� silver USD/kg 650.00<br />
Costs of ore mining USD/t 2.00<br />
Costs of waste mining USD/t 2.00<br />
Costs of flotation ore processing USD/t 3.80<br />
Costs of metallurgical treatment of copper<br />
USD/t Cu 750.00<br />
concentrate<br />
cathode<br />
Gold refining costs USD/kg 150.00<br />
Silver refining costs<br />
Flotation efficiencies<br />
USD/kg 15.00<br />
� copper % 82.0<br />
� gold % 55.0<br />
� silver<br />
Metallurgy recoveries<br />
% 55.0<br />
� copper % 95.0<br />
� gold % 91.0<br />
� silver % 91.0<br />
Annual ore processing capacity t/year 8 500 000<br />
Discount rate % 10<br />
4. ECONOMIC LIMITS OF<br />
DEPOSIT EXCAVATION AND<br />
CALCULATION THE BALANCE<br />
ORE RESERVES<br />
Determination of economic limit of<br />
deposit excavation by open pit, i.e. determination<br />
the limit open pit for mentioned<br />
starting techno-economic parameters, was<br />
carried out using the software package for<br />
optimization the open pit, Whittle, based<br />
on developed block model of deposit.<br />
The mentioned software package sets<br />
the open pit limit per Lersh-Grossman<br />
algorithm, and the Cut-off procedure was<br />
applied. This method is used to calculate a<br />
potential profit for each mineralized block<br />
and costs in the event of its excavation.<br />
For one combination of technoeconomic<br />
parameters, one limit open pit is<br />
obtained, but the contour of limit open pit<br />
is changed by changing of some input<br />
parameters. Software has the abilities to<br />
change the size of revenues using the coefficient<br />
of metal price and thus to generate<br />
a number of possible open pit contours,<br />
as shown in Figure 1.<br />
Changing the metal prices, i.e. potential<br />
revenue, different limits of open pit were<br />
defined by applying the revenue factor. It is<br />
also read from graphic the total quantity of<br />
excavation (ore and waste) that are affected<br />
by open pit as well as the characterized<br />
quantities by software as the ore.<br />
No 4, 2011. 89<br />
MINING ENGINEERING