Ebrahim Elahi Zeyni - Department of Mining Engineering, University of Sistan and Baluchestan, Zahedan, Iran.
Seyed Mohammad Esameil Jalali - Department of Mining, Petroleum and Geophysics Engineering, Shahrood University of Technology, Shahrood, Iran.
Reza Khalo Kakaei - Department of Mining, Petroleum and Geophysics Engineering, Shahrood University of Technology, Shahrood, Iran.

In the open-pit mining method, it is necessary to design the ultimate pit limit before mining to determine issues, such as the amount of minable reserve, the amount of waste removal, the location of surface facilities, and production scheduling. If the obtained profit from the extraction of the pit limit becomes maximum, it is called the optimum pit limit. Various algorithms have been presented based on heuristic and mathematical logic for determining the optimum pit limit. Several algorithms, such as the floating cone algorithm and its corrected forms, the Korobov algorithm and its corrected form, dynamic programming ۲D, the Lerchs and Grossmann algorithm based on graph theory have been presented to find out the optimum pit limit. Each of these algorithms has particular advantages and disadvantages. The designers of the corrected form of the Korobov algorithm claim that this algorithm can yield the true optimum pit in all cases. Investigation shows that this algorithm is incapable of yielding the true optimum conditions in all models, and in some models the method produces an optimum with a negative value. In this paper, this algorithm has been evaluated, and a modification model is also presented to overcome its disadvantage. This new algorithm was named the Korobov algorithm III. In this paper, this new algorithm was considered in different models of two and three-dimensional space. A case study for designing of the optimum pit limit in three-dimensional space was done for a gold mine in the sewed country. The outcomes of Table ۹ show that this new method designs a pit limit with a value of ۶۹۴۲۸.۵۹ that has better results than previous Korobov algorithms.

Open pit mining, Ultimate pit limit, Korobov algorithm