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Once the performance characteristics of a system have been determined, engineers are often faced with the task of identifying the critical components. The objective of this identification is to prioritise improvements in the systems and the efforts to bring these about in the areas that will have the most effect on the system's performance. Availability is an important metric, used to assess the performance of complex systems. Having the availability importance measure (AIM), which determines the importance of items regarding the availability of the system, can help designers and managers to improve performance and minimise the life cost of the system. This paper has developed an AIM for complex systems. Thereafter, the application of the developed importance measure is illustrated by a case study. [ABSTRACT FROM AUTHOR]

An improvement for rock engineering system (RES) coding method is done in this paper by using fuzzy systems. A fuzzy expert semi-quantitative coding methodology is designed to assess the cavability of rock mass within the RES framework. The proposed fuzzy method has the advantage of allowing consideration of uncertainties in the RES analysis by using membership functions in comparison with classic expert semi-quantitative coding method that only unique codes are used to quantify the interaction matrix. Since the cavability of the rock mass is one of the fundamental issues for the caving mining method, the presented improved coding method is creatively used to assess the influencing parameters on cavability of rock mass in block caving mines. Fifteen parameters are considered as the main factors modeling the cavability of the rock mass, and the interactions between these parameters are calculated by proposed fuzzy system. Finally in this paper, the parameters, which are dominant or subordinant, and also the parameters, which are interactive, are introduced. The proposed approach could be a simple but efficient tool in evaluation of the parameters affecting the cavability of rock mass in block caving mines and hence be useful in decision making under uncertainties. [ABSTRACT FROM AUTHOR]

One of the major strengths of a GIS is the ability to integrate and combine multiple layers of geoscience data for producing mineral potential maps showing favorable areas for mineral exploration. Once the data is prepared properly, the GIS, jointly with other statistical and geostatistical software packages, can be used to manipulate and visualize the data in order to produce a mineral prospectivity map. Many spatial modeling techniques can be employed to produce mineral potential maps. This paper demonstrates a technique to define favorable areas for REE mineralization with AHP technique using geological, geochemical, geophysical, alteration and faults density spatial data in the Kerman-Kashmar Tectonic Zone of central Iran. The AHP is a powerful and flexible multi-criteria decision-making tool for dealing with complex problems where both qualitative and quantitative aspects need to be considered. This approach is knowledgedriven method and can be applied in other areas for conventional use in mineral exploration. [ABSTRACT FROM AUTHOR]

Knowledge of drillability of rock masses in engineering projects is very important in determining drilling costs. In drilling operations, so many parameters such as the properties of rock and the drilling equipment affect the drilling performance. In this study, after discussing the rock mass drillability process and identifying all the effective parameters, interaction matrixes based on the rock engineering systems, that analyze the interrelationship between the parameters affecting rock engineering activities, is introduced to study the rock mass drillability tribosystem. Given that interaction matrix codes are not unique numbers, and then possible interactive intensities are calculated for each matrix and a group decision-making method, Fuzzy-Delphi-AHP technique has been used to obtain appropriate weights. As a result, rock mass drillability index (RMDI) is presented to classify the rock mass drillability. The results indicate the ability of this method to analyze rock mass drillability procedure. Drilling data along with laboratory rock properties from Sungun copper mine were collected and were ranked according to the new classification system. Fifteen zones at the mine site were ranked based upon the new index RMDI and a reasonable correlation was obtained between measured drilling rate at the zones and RMDI data. [ABSTRACT FROM AUTHOR]

Abstract: Underground mining method selection is one of the most crucial decisions that should be made by mining engineers. Choosing a suitable underground mining method to carry out extraction from a mineral deposit is very important in terms of the economics, safety and the productivity of mining operations. The aim of this study is developing a fuzzy model to selection the optimum mining method by using effective and major criteria and at the same time, taking subjective judgments of decision makers into consideration. Proposed approach is based on the combination of fuzzy analytic hierarchy process (FAHP) method with an advanced type of conventional AHP. FAHP is used in determining of the weights of the criteria by decision makers and then rankings of the methods are determined by AHP. The proposed method is applied for Jajarm Bauxite Mine in Iran and finally the most appropriate mining methods for this mine are ranked. [Copyright &y& Elsevier]

Abstract: The main purpose of this study is to compare the many different rock properties in the rock sawability. The comparison was realized with the combination of the analytic hierarchy process (AHP) and Fuzzy Delphi method and also TOPSIS method. The analysis is one of the multi-criteria techniques providing useful support in selecting among several alternatives with different objectives and criteria. FDAHP method was used in determining the weights of the criteria by decision makers and then ranking the sawability of the rocks was determined by TOPSIS method. The study was supported by the results obtained from a questionnaire carried out to know the opinions of the experts in this subject. During the research process, the rock sawability was evaluated in terms of production rate of sawn rock. Prediction of production rate is important in the cost estimation and the planning of the stone plants. The new developed ranking method may be used for evaluating production rate of ornamental stone at any stone factory with different stone. Some factors such as uniaxial compressive strength, Schmiazek F-abrasivity, mohs hardness and Young’s modulus must be obtained for the best production rate ranking. [Copyright &y& Elsevier]