A OPEN PIT MINING AÇIK OCAK MADENCİLİĞİ

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23 rd
Figure 6. Ultimate pit limit based on gradetonnage
curve (not blend pit) and optimized
pit-blend
6 DISCUSSIONS AND CONCLUSIONS
Pit limit is a set of those blocks that are
profitable to be exploited by open pit mining
methods. There are a number of pit design
algorithms which require that the economic
value of each block to be determined prior to
applying the algorithms. In traditional pit
limit optimization techniques, one cannot
take into account the requirements of
blending. Some commodities such as iron
ore, coal, limestone, and industrial minerals
that are direct shipped need to be blended to
provide a product that suits consumer’s
requirements. In order to determine the
economic value of these blocks, one needs to
first select the set of blocks that can be
blended. After this, one could apply any
available method to determine the ultimate
pit limit (UPL). In this paper a combined
approach is used to determine the pit limit of
an open pit mine considering the
requirements of blending. In this approach,
using a self-adaptive differential evolution
algorithm, called jDE, first those ore blocks
that meet the blended product requirements
are selected, and then the ultimate pit limit is
determined using maximum flow theory. The
resulting pit is a combination of those blocks
that are profitable to be exploited by open pit
mining and are capable of being shipped
directly. This method is helpful in
conducting a better production plan with
regard to satisfy the consumer’s
requirements.
The proposed blending model is an integer
programming model and it is solved using
jDE algorithm. The jDE is a fast algorithm
for solving large optimization problems. In
determining the pit-blend limit for the mine,
the time of extracting the block is not
considered. It is an obligation for the mine to
produce a final product with a stable quality.
So, using the pit-blend optimizer for long
term planning may not be useful, but,
determination of an optimized pit-blend limit
is very helpful in medium term and short
term mine planning.
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