Showing papers by "Kourosh Shahriar published in 2011"

Uncertainty and Reliability Analysis Applied to Slope Stability: A Case Study From Sungun Copper Mine

Abstract: Nowadays, there are many new methods for slope stability analysis; including probabilistic methods assessing geotechnical uncertainties to develop safety factors. In this paper, a reliability index analysis for the Sungun copper mine slope stability is evaluated based on three methods of uncertainties consisting Taylor series method, Rosenblueth point estimate method and Monte-Carlo simulation method. Sungun copper mine will be one of the Iran’s biggest mines with final pit’s height of 700 meters. For this study two of its main slopes were assessed, one dipping to the NE (030) and the other to the SE (140). Probability density function of cohesion and angle of friction for the slopes were developed using limit equilibrium methods. These shear strengths were then used to determine the probability density function of safety factor and reliability index using the probabilistic methods. Results of the probabilistic analysis indicate that with ascending values of the uncertainties the reliability index decreases. Furthermore, it was determined that with the Monte Carlo simulation the seed number used has little effect on the reliability index of the safety factor especially with seed numbers in excess of 1200. Variations in the overall reliability index of safety factor were observed between the two slopes and this difference is explained by the differences in complexities of the geology within the cross-section.

A model to predict the performance of roadheaders based on the Rock Mass Brittleness Index

Abstract: Synopsis Roadheaders are very versatile excavation machines used in tunnelling, mine development, and mine production for soft to medium strength rock formations. Performance prediction is an important factor for successful roadheader application and generally deals with machine selection, production rate and bit consumption. Among many different parameters, brittleness is also one of the material properties related to breakage characteristics and can be used as a cuttability parameter from a mechanical excavation point of view. The main objective of the research study is to contribute the brittleness of rock excavated to construct a new empirical equation for predicting the performance of roadheaders in different material and operational conditions. In this regard, a new performance prediction model for medium duty roadheaders based on a brittleness index (BI) is presented. In this study, rock mass brittleness index (RMBI) is defined in order to investigate the influence of BI on roadheader performance. RMBI is an index which can be used to relate the intact and rock mass characteristics to machine performance. Results demonstrated that RMBI is highly correlated to instantaneous cutting rate (ICR) (R²=0.94). Moreover, through the further analysis and normalization, the pick consumption index (PCI) was introduced as a parameter having a good relation with pick or bit consumption rates (PCR) (R²=0.79). Finally, the new predictive models for ICR and PCR showed very good correlations with the actual measured values.

Environmental impact assessment of mining activities. a new approach for mining methods selection

Abstract: One of the main tasks in exploitation of mineral deposits is to select a method suitable for the deposits specific features. Characteristics that have a major impact on the determination of the mining method includes: physical and geologic characteristics of the deposit, ground condition of the hanging wall, footwall, and ore zone, mining and capital cost and rate, availability and cost of labor, environmental consideration. The selection of a mining method is shifting from an activity that is primary an art to one that is primarily science (Hartman, Mutmansky 2002). It should be noted that there is no single appropriate mining method for a deposit; there are usually two or more feasible method. Each method entails some inherent problems. Consequently, the optimum method is that method with the least problems. The factors that determine the mining method selection for exploitation of the deposit are grouped in six categories (Hartman, Mutmansky 2002): — Spatial characteristics of the deposit. — Geologic and hydrology conditions. — Geotechnical properties. — Economical consideration.

Application of the Strain Energy to Estimate the Rock Load in Non-Squeezing Ground Condition

Abstract: Estimation of rock load is very important issue because the selection of support system is highly related to this parameter. Several methods are used to estimate this parameter such as experimental, empirical and numerical methods. In this study, a new empirical method is proposed to estimate the rock load based on the ration of the residual strain energy of post failure to the stored strain energy of pre failure. Also a statistical analysis is performed through collected actual data from fi ve tunnels in non squeezing condition. The result showed that there is a direct relationship between both parameters and the good correlation between both parameters is achieved by using of power equation to estimate of rock load in non squeezing condition.

Application of the strain energy to estimate the rock load in non-squeezing ground condition zastosowanie energii odkształceń do estymacji obciążenia górotworu w warunkach braku osiadania gruntu

Abstract: Estimation of rock load is very important issue because the selection of support system is highly related to this parameter. Several methods are used to estimate this parameter such as experimental, empirical and numerical methods. In this study, a new empirical method is proposed to estimate the rock load based on the ration of the residual strain energy of post failure to the stored strain energy of pre failure. Also a statistical analysis is performed through collected actual data from fi ve tunnels in non squeezing condition. The result showed that there is a direct relationship between both parameters and the good correlation between both parameters is achieved by using of power equation to estimate of rock load in non squeezing condition.