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A OPEN PIT MINING AÇIK OCAK MADENCİLİĞİ

A OPEN PIT MINING AÇIK OCAK MADENCİLİĞİ

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23 rd <br />

6 THE HIERARCHICAL<br />

PREFERENCE VOTING SYSTEM<br />

Proper haulage system can be considered a<br />

hierarchical structure, then it can be called<br />

hierarchical preference voting system<br />

(HPVS) (Figure 5). The figure includes<br />

objective of the problem in the upper level,<br />

m criteria in the intermediate level and n<br />

decision alternatives in the lower level.<br />

Criteria<br />

Table 2- Structure of preference voting<br />

system for criteria<br />

IL<br />

1<br />

w<br />

1<br />

C<br />

1<br />

v<br />

11<br />

…<br />

…<br />

Importance Levels<br />

IL … IL<br />

p<br />

…<br />

k<br />

Weights of importance levels<br />

… w<br />

k<br />

… w<br />

p<br />

Vote of each criterion in each<br />

ranking place<br />

… v 1 k<br />

… p<br />

…<br />

…<br />

…<br />

Total Scores<br />

v TC p<br />

1 v w k 1 1 k k<br />

…<br />

…<br />

Weights<br />

W<br />

1 1<br />

…<br />

p<br />

C<br />

j<br />

v<br />

j1<br />

… v<br />

jk … v<br />

jp TC<br />

j<br />

<br />

v w<br />

W<br />

k 1 jk k j<br />

…<br />

…<br />

…<br />

…<br />

…<br />

…<br />

…<br />

…<br />

Figure 5- Hierarchical structure of problem<br />

7 RANKING CRITERIA AND<br />

CALCULATING THEIR RELATIVE<br />

WEIGHTS<br />

The preference voting system was used to<br />

calculate relative weight of each criterion.<br />

Applying group decision making in methods<br />

that mentioned in literature, requires much<br />

computational effort, while PVS needs less<br />

calculations. The structure of PVS for<br />

criteria is shown in Table 2.<br />

To characterize the relative importance of<br />

each criterion, a set of importance levels<br />

were defined as ranking places: {IL 1 , ..., IL k ,<br />

..., IL p }, where IL 1 , ..., IL k , ..., IL p represent<br />

the importance from the most to the least and<br />

p is the number of importance levels. The<br />

decision makers were asked, from different<br />

domains to assess criteria in p importance<br />

levels. v jk s are the numbers of the decision<br />

makers who assess criterion j (C j ) in<br />

importance level IL k (k = 1, ..., p).<br />

Let w k be the weights associated with<br />

importance levels IL k (k = 1, ..., p). Using<br />

model (4) we calculated weights for each<br />

importance level. The total score of each<br />

criterion could be obtained by following<br />

equation:<br />

p<br />

TC<br />

j<br />

<br />

vmk<br />

w<br />

1 k<br />

(7)<br />

k<br />

p<br />

C<br />

m<br />

v<br />

m1<br />

… v<br />

mk … v<br />

mp TCm<br />

k<br />

<br />

vmk<br />

w<br />

1 k<br />

W m<br />

Where TC j is the total score obtained by<br />

criterion j. Using these scores, it is possible<br />

to rank the criteria. After normalizing these<br />

scores, the weights associated with each<br />

criterion (W j ) could be calculated.<br />

8 CASE STUDY<br />

In this study, the selection of proper haulage<br />

system of Sarcheshmeh copper mine in Iran<br />

was done by PVS method.<br />

Sarcheshmeh is a large open pit copper<br />

mine in the Kerman Province of Iran, the<br />

Sarcheshmeh Copper Complex is located<br />

65 km southwest of Kerman and 50 km<br />

south of Rafsanjan. Production units of<br />

Sarcheshmeh Copper Complex involves the<br />

mine itself, concentrator, smelter, refinery,<br />

foundries and leaching.<br />

The deposit is known as a typical<br />

porphyry copper deposit with respect to<br />

alteration types, mineralization style, ore<br />

grade and size, tectonic setting, and igneous<br />

rock features (Waterman & Hamilton, 1975).<br />

In the development plan of Sarcheshmeh<br />

copper mine, the mine depth will reaches to<br />

837.5 meter at 2062.5 level. Average<br />

haulage distance will reach to 4.5 km, by<br />

increasing the depth of the mine.<br />

To select the suitable haulage system for<br />

Sarcheshmeh copper mine, among the<br />

possible methods, three methods were<br />

identified as the most appropriate methods.<br />

These methods are truck & shovel,<br />

combination of truck-shovel & in-pit crusher<br />

and shovel & mobile in-pit crusher.<br />

135

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