Igor Miljanović

Design, implementation and control of mineral processing systems are complex processes requiring accurate decision making that often needs to be real-time. In certain cases, the problems can be described by a single function or criterion. However, most often, multiple criteria are involved, often mutually non-aligned or even conflicting. Selection of a flotation collector is a distinctive multicriteria problem where the decision-making problem must be completed even with imprecise, uncertain or unverified/missing data. The paper considers three different rough set approaches for the process of selection of a flotation collector for the rougher flotation of copper minerals. First is the dominance-based rough set approach (DRSA), second a rough-fuzzy approach and the third is a rough-grey approach by rough number-enabled grey relation analysis. The DRSA and the rough-fuzzy approach produced identical ranking of collectors, while the rough-grey approach produced a very similar ranking with reversed positions of the two highest ranked collectors. The results were also compared with PROMETHEE and ELECTRE methods’ results, which were very similar to the rough set-based methods, showing that these approaches can support collector selection in the circumstance of imprecise or uncertain data.

Multiple criteria decision making (MCDM) is a supporting tool which is widely spread in different areas of science and industry. Many researchers have confirmed that MCDM methods can be useful for selecting the best solution in many different problems. In this paper, two novel methods are presented and applied on existing decision-making processes in the mining industry. The first method is multiple criteria ranking by alternative trace (MCRAT) and the second is ranking alternatives by perimeter similarity (RAPS). These two novel methods are demonstrated in decision-making problems and compared with the ranking of the same alternatives by other MCDM methods. The mining process often includes drilling and blasting operations as the most common activities for exploitation of raw materials. For optimal blasting design it is important to select the most suitable parameters for the blasting pattern and respect characteristics of the working environment and production conditions. By applying novel methods, how to successfully select the most proper blasting pattern respecting all conditions that must be satisfied for economic aspects and the safety of employees and the environment is presented.

The task of connecting survey and orienting mine rooms is to obtain the coordinates for the first point of the future underground traverse and the bearing of the first side of the underground traverse on the horizon that is being connected. The task is particularly complex when the connection survey is performed through a single vertical shaft. The accuracy of connection survey and orientation is influenced by the errors in given and measured values, but in addition a question may be asked if the applied calculation method influence the connection precision (accuracy) and if they do to what extent. If the connection through a single vertical shaft is completed by the connection rectangle method, the calculations are most often done by using the Hansen, Weiss or Hause method. This paper presents calculations of standard deviations of unknown values in a connecting rectangle based on the three methods, as well as standard deviations of the bearing of the first side of the underground traverse on an example.

In this paper, an analysis of the possibility of implementing the fuzzy logic and artificial neural network controller in the intelligent control system in the flotation plant Veliki Krivelj was performed. Functional positioning of controllers was considered through two approaches. According to one approach, the control of flotation process would be carried out by only one controller, while in the second case two controllers would exist - one for a rough flotation and scavenging and the other for cleaning.

This paper discusses the application of the PROMETHEE model and the results achieved in practice, following the example of the multi-criteria selection of the technological system at the Majdan III clay mineral raw material open pit mine of the Potisje Company, Republic of Serbia. After the introduction comments, reasons are explained for selecting the new technological system, conditions and limitations for the seven alternative solutions considered are described, mathematical foundation for the PROMETHEE method and a multi-criteria model of the problem in question are presented. The solution with the following structure was ranked first and accepted by the Company management as the best: Bucket chain excavator - Conveyor belts - Spreader (ECS), alongside a decision is made on the acquisition of machinery and system construction. The system was put into operation in 2000. The experience and the data accumulated in the previous twelve years confirm that the decision made on the application of the ECS technology was just, and the conclusion lists the benefits achieved.

Flotation tailings dumps represent a potential threat to the environment. To corroborate this, numerous environmental disasters have occurred worldwide in the past. Pollution caused by breaking of tailings dump dams and overflowing of hazardous materials is still present, after several decades, and continue to threaten the environment. This paper presents a method for determining the most appropriate location for the flotation tailings dump using rough set theory. The review of the criteria that influence the choice of flotation tailings dump location is given. Based on these criteria, an analysis and evaluation of the proposed locations for the flotation tailings dump are done using rough set theory and the most suitable location that meets all the requirements is suggested.

The objective of the resented comparative analysis of the effect of biological "reinforcement" compared to reference loess soil was to define: the increase in the value of resistance parameters on shear and the decrease in the value of seepage stream parameters. The contradictory effect of biological "reinforcement" on the above parameters leads to the increase in the total soil resistance to the formation and development of all forms of internal erosion. Biologically "reinforced" soil, compared to reference loess soil shows the changes in both physical-mechanical characteristics and seepage stream indicators of internal erosion. Aiming at a more complex analysis of the problem of internal erosion, it is indispensable to analyse also the effect of the presence of roots in the soil on the occurrence and development of internal erosion. The comparative analysis of the effects of biological "reinforcement" on physical and mechanical characteristics of the soil, as well as the practical implementation of the results in practice have been made possible by the formed mathematical models and the established functional relations between water regime and resistance characteristics of the reference soil and biologically "reinforced" soil.

The paper presents one of the possible approaches to fuzzy logic modeling of coal cleaning in autogenous suspension. In the scope of reviewing the problem in general, the process algorithm and the structural model of coal cleaning were set up. The paper deals with the flow of fuzzy logic model creation following the example of coal cleaning plant of the “Bogutovo selo” open pit mine of the Mine and Thermal Power Plant Ugljevik. The model is set up on the MATLAB software platform. Fuzzy model testing results, presented at the end of paper confirms applicability and reliability of the model. The discrepancies between the model and the real process parameters are within the limits of allowed industrial error.