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This paper considers simulation of truck dispatching system designs using maximum expected production of the truck-shovel system as the measure of perfommnce. Two methods are utilized, multiple comparisons with the best (MCB) and the combination of MCB and the variance reduction technique known as common random numbers (CRN). These two techniques are compared via simulation experiments.The results show that the combined procedure of MCB with CRN is the superior tool to reduce the total number of replications needed to ensure the specified probability of correct selection over the finite number of designing systems.In this case study, MCB with CRN reduces the variance by 29°/0 and the number of required replications by 48Y0. Also, the MCB with CRN procedure narrowed the confidence interval by 18°/0.

Purpose This paper aims to develop a system, which would enable efficient management and exploitation of documentation in electronic form, related to mining projects, with information retrieval and information extraction (IE) features, using various language resources and natural language processing. Design/methodology/approach The system is designed to integrate textual, lexical, semantic and terminological resources, enabling advanced document search and extraction of information. These resources are integrated with a set of Web services and applications, for different user profiles and use-cases. Findings The use of the system is illustrated by examples demonstrating keyword search supported by Web query expansion services, search based on regular expressions, corpus search based on local grammars, followed by extraction of information based on this search and finally, search with lexical masks using domain and semantic markers. Originality/value The presented system is the first software solution for implementation of human language technology in management of documentation from the mining engineering domain, but it is also applicable to other engineering and non-engineering domains. The system is independent of the type of alphabet (Cyrillic and Latin), which makes it applicable to other languages of the Balkan region related to Serbian, and its support for morphological dictionaries can be applied in most morphologically complex languages, such as Slavic languages. Significant search improvements and the efficiency of IE are based on semantic networks and terminology dictionaries, with the support of local grammars.

The power plant owner is interested to know in advance the quality of coal to be burnt which should meet maximal efficiency of power plant and the environmental regulations. There is the need to control and to predict the quality of coal at the mine site to meet sulfur emission requirements. Coal quality control between the mine site and the utility plant is a complex problem owing to the variable nature of coal properties (heating value, sulfur, ash), even within the same coal seam. Due to the fluctuation of the coal quality, mine planning and coal homogenization are in fact an optimization problem under uncertain conditions. To deal with these issues a stochastic optimization model is developed for an illustrative coal homogenization problem. Mining block grades from an optimized mining schedule are used to simulate any given homogenization process in stockpiles throughout the mine's life. Sulfur content is treated as lognormally distributed random variable. The objectives of the model include minimizing the expected sulfur content and standard deviation in sulfur content. The methodology was illustrated using the case study on Kolubara surface coal mine.

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Profitable exploitation of mineralised material from the earth's crust is a complex and difficult task that depends on a comprehensive planning process. Answering the question of how to plan production depends on the geometry of the deposit, as well as the concentration, distribution, and type of minerals in it. The complex nature of mineral deposits largely determines the method of exploitation and profitability of mining operations.In addition to unit operating costs and metal prices, the optimal recovery of and achievement of maximum profit from deposits of sulphide-oxide ores also depend, to a significant extent, on the level of technological recovery achieved in the ore processing procedure.Therefore, in defining a long-term development strategy for open pits, special attention must be paid to the selection of an optimal procedure for ore processing in order to achieve the main objective: maximising the Net Present Value (NPV).The effect of using two different processes, flotation processing and hydrometallurgical methods (bioleaching acid leaching), on determining the ultimate pit is shown in the case of the Kraku Bugaresku-Cementacija sulphide-oxide ore deposit in eastern Serbia. Analysis shows that the application of hydrometallurgical methods of processing sulphide-oxide ore achieved an increase in NPV of 20.42%.Keywords: long-term planning, optimisation, bioleaching, acid leaching, Net Present Value Przynosząca zyski eksploatacja kopalin wydobywanych ze skorupy ziemskiej jest zadaniem złożonym i trudnym, wymagającym całościowego planowania. Aby określić w jaki sposób zaplanować prace wydobywcze, należy uwzględnić geometrię złoża, a także rozkład, koncentrację i rodzaj zawartych w złożu minerałów. Złożony charakter złóż minerałów w dużej mierze determinuje wybór metod wydobycia oraz poziom zysków. Obok jednostkowych kosztów produkcji oraz cen metali, optymalna eksploatacja złóż rud siarczkowych i osiągniecie maksymalnych zysków w dużej mierze zależą także od zastosowanych technologii uzyskiwania metalu z rud. Przy definiowaniu długoterminowej strategii wydobycia rud w kopalni odkrywkowej uwzględnić także należy wybór optymalnej metody obróbki rud w celu uzyskania założonego celu: maksymalizacji wartości bieżącej netto (NPV -Net Present Value). Wykorzystanie dwóch procesów: flotacji oraz metod hydro-metalurgicznych (bio-wypłukiwanie, ługowanie) przedstawiono dla rozważanego przypadku kopalni odkrywkowej rudy siarczkowej eksploatującej złoże w regionie Kraku-Bugaresku-Cementacija we wschodniej Serbii. Analizy wskazały, że zastosowanie metod hydro--metalurgicznych zapewnia wzrost wartości bieżącej netto o 20.42%.Słowa kluczowe: planowanie długoterminowe, optymalizacja, bio-wypłukiwanie, ługowanie kwasowe, wartość bieżąca netto (NPV)

The influence of sized zeolite product range on the ability of adsorption has been studied by numerous researchers. Research in this area has mostly concentrated on natural zeolite, production results that can be used in the application of zeolite products for animal feed or water purification. Researchers use the following range of size classes for this purpose: powder, -5 +2 mm, -2 +0.5 mm, -2 +0 mm, -2.4 + 1.4 mm, -1.4 +0.4 mm, -0.4 +0 mm, -0.1 +0 mm, -0.8 +0.6 mm, -0.5 +0 mm, -0.5 +0.315 mm, -0.15 +0.075 mm, -0.090 +0.063 mm, -0.5 +0.1 mm, -0.1 +0.04 mm; -+0 0.63 mm, -0.2 +0 mm, -0.043 +0 mm, -0.1 +0.063 mm. In the paper entitled "Structural and Physico-chemical Properties of Natural Zeolites: Clinoptilolite and Mordenite", the fractions of clinoptilolite with the particle size ds = 0.355-0.5 mm and mordenite of ds = 0.2-0.315 mm were chosen for examination (Korkuna et al. 2006). For studying the adsorption of arsenic (V) from a water solution onto a surfactant-modified zeolite, the authors Mendoza- Barron et al. (2011) used modified natural zeolite from the deposit located in San Luis Potosi, Mexico. The sample was ground and sieved to an average particle size of 0.42 mm . Natural clinoptilolite zeolite from the Donje Jasinje deposit was used in three size classes: -0.5 mm, -2 +0.5 mm and -5 +2 mm, in the paper "Kinetics and Thermodynamics Study of Copper Li et al. (2009) investigated the adsorption of chromates on natural zeolite by the modified surfactants. They used the following zeolite fractions: 3.6-4.8 mm, 1.4-2.4 mm and < 0.4 mm. It was confirmed that adsorption of chromates increases with a decrease in zeolite particle size. Despite the fact that with an increase in particle size the adsorption of a specific pollutant decreases, it was also pointed out that larger particle size is required in order to achieve better hydraulic properties, and that, due to this fact, it is important to examine the effects of particle size on adsorption of the specific pollutant. Unlike most of the clay minerals and their property of swelling in water, zeolites have tighter three-dimensional crystal structure, and thus hydraulic properties that enable a wider range of applications in purifying contaminated water (Huggerty et al. 1994; Zhaohui Li et al. 1997; Sheng et al. 1997). Due to the inverse proportionality between the grain size and specific surface in the adsorption experiments with various contaminants in natural zeolite, it is necessary to test the effect of grain size on adsorption the specific contaminant (Lemiae 2006).If too low a cation exchange capacity (CEC) value of the ground class -0.1 +0 mm sample is obtained, after crushing the starting sample to the class -3 +0 mm, the classification can be applied and then the class -0.1 +0 mm with satisfying CEC value can be separated. A higher CEC value can also be obtained from the rest of the classification, i.e. in the +0.1 mm class, and grinding of that class will provide the desired quality of the class -0.1 +0 mm. Therefore, testing the zeolite quality...

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