OPEN PIT MINE DESIGN OPTIMIZATION by FLOATING SLOPES METHOD

In the last decades of the 20th century, growing processing power of computers has made possible to apply a number of methods for the determination of ultimate pits. These methods are: Lerchs-Grossmann method (Lerchs & Grossmann, 1965; Alford & Whittle, 1986),



network or maximal flow techniques (Johnson & Barnes, 1988; Yegulalp & Arias, 1992), floating cone method (Berlanga et al., 1988; Lemieux, 1979), the Korobov algorithm (Korobov, 1974), the corrected form of the Korobov algorithm (Dowd & Onur, 1993), parameterization techniques (Matheron, 1975; François-Bongarçon & Guibal, 1982) and dynamic programming method (Johnson & Sharp, 1971; Koenigsberg, 1982; Wilke & Wright, 1984; Wright, 1987; Yamatomi et al., 1995), which assumptions and algorithms determine the today’s direction of the design in open pit mining. The algorithms of above counted methods are the core of the programs which are used in the computer designing methods. The main goal of these methods, almost all of which are based on block models, is the optimal open pit outline with the steepest dip of the final slopes under technological and physical constraints, and minimal costs of mining desirable blocks, in other words the maximum net profit.
Complexity of the geological conditions of a deposit and dynamism of the economical indicators define the choice of the most adequate method of design for the mining operation (Galić, 2002).
Methods mentioned above are made for the applications on the large open pits of metal deposits, which place serious question on their use on bedded deposits (nonmetallics and coal). That is, in bedded deposits of nonmetallics, especially in case of the inclined bedrock with crushed stone and dimension stone deposits including coal deposits, the number of unknowns for planning in mine design essentially diminishes in respect to the metal deposits. That can be easily explained because it is typical for metal deposits to have highly variable shapes, sizes, and often highly erratic distribution of valuable minerals within a deposit, which certainly presents complex work conditions for the mining operations. On the over hand we have coal deposits, where the footwall of high-grade layer usually presents one of the final slopes. Furthermore, oscillation, respective change of the ore grade in nonmetal deposits is much smaller in extent on the contrary to the metal deposits. These facts have encouraged authors to suggest and to test a new design method for open pit mines for primarily inclined bedded deposits of nonmetallics and coal, but it can be also applied on other types of deposits.

Keywords: open pit optimization, bedded deposits, block model, maximum net profit
 
Ključne riječi: optimalizacija, površinski kop, slojevita ležišta, blok model, maksimalna neto dobit


AN ANOTHER WAY FOR OPEN PIT MINE DESIGN OPTIMIZATION – FLOATING SLOPES METHOD


NOVI NAČIN OPTIMALIZACIJE KONTURA POVRŠINSKIH KOPOVA – METODA POMIČNIH KOSINA

by IVO GALIĆ, BRANIMIR JANKOVIĆ, IGOR MRAKOVČIĆ

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