Iraj Alavi; Arash Ebrahimabadi; Hadi Hamidian
Abstract
Estimating the costs of mine reclamation is a significant part of mine closure projects. One approach to mine reclamation is planting mine areas. In this approach, the optimum selection of plant types is cosidered a multiple-criteria decision-making (MCDM) problem. Once proper plant species are identified, ...
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Estimating the costs of mine reclamation is a significant part of mine closure projects. One approach to mine reclamation is planting mine areas. In this approach, the optimum selection of plant types is cosidered a multiple-criteria decision-making (MCDM) problem. Once proper plant species are identified, it is required to estminate planting costs through statistical analysis. This work aims to introduce an algorithm for optimal plant type selection and a reclamation cost estimation model for open-pit mines. To this end, the plant species compatible with the sorrounding areas of Sungun copper mine are identified and ranked using the PROMETHEE technique. In this analysis, the main criteria are local landscape, pest resistance, plant growth ability, availability, economic issues, soil protection, water storage ability, and pollution prevention. Among the six plant types, Maple trees have the highest score (4.34). After that, to develop the reclamation cost estimation model, the data (99 datasets) is collected from the Sungun copper mine, Sarcheshmeh copper mine, and Chadormaloo iron mine. The variables in the database include soil gradation by graders, slope trimming and topography by bulldozers, the ripping and softening of the compacted soil, chemical fertilizers, natural fertilizers and mulch and biosolid, lime soil pH adjustment, herbicide, seedling, tree planting, workers and drivers, and fuel and maintenance. Regression analysis is performed to analyze the data, and a reclamation cost estimation model is developed with high accuracy (R2 = 0.78). On the whole, this study proposes an innovative, step-by-step, technical, and economic approach to the optimal selection of plant species, and presents a reclamation cost estimation model so as to promote the open-pit mine reclamation process.
E. Pouresmaeili; A. Ebrahimabadi; H. Hamidian
Abstract
Sustainability assessment has received numerous attentions in the mining industry. Mining sustainability includes the environmental, economic, and social dimensions, and a sustainable development is achieved when all these dimensions improve in a balanced manner. Therefore, to measure the sustainability ...
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Sustainability assessment has received numerous attentions in the mining industry. Mining sustainability includes the environmental, economic, and social dimensions, and a sustainable development is achieved when all these dimensions improve in a balanced manner. Therefore, to measure the sustainability score of a mine, we require an approach that evaluates all these three dimensions of mining sustainability. Some frameworks have been developed to compute the sustainability score of mining activities; however, some of them are very complicated and the others do not cover all the environmental, economic, and social aspects of sustainability. In order to fill this gap, this work was designed to introduce a practical approach to determine the score of mining sustainability. In order to develop this approach, initially, 14 negative and positive influential macro factors in the sustainability of open-pit mines were identified. Then the important levels of the factors were estimated based on the comments and scores of some experts. Two checklists were constructed for the negative and positive factors. The sustainability score was computed using these checklists and the importance levels of the factors. The score range was between -100 and +100. In order to implement the proposed approach, the Angouran lead and zinc mine was selected. The sustainability score of the Angouran mine was +47.91, which indicated that the this mine had a sustainable condition. This score could increase through modification of some factors.
F. Sadough Abbasian; B. Rezai; A. R. Azadmehr; H. Hamidian
Abstract
In this work, two clay-based composites are prepared for the adsorptive removal of the chloride ions from aqueous solutions. These composites are characterized through Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction analysis. ...
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In this work, two clay-based composites are prepared for the adsorptive removal of the chloride ions from aqueous solutions. These composites are characterized through Fourier transform-infrared spectroscopy, scanning electron microscopy, X-ray fluorescence spectroscopy, and X-ray diffraction analysis. The effects of different parameters such as the contact time, amount of adsorbent, chloride concentration, temperature, and pH are studied by batch experiments. Also the isotherm, kinetic, and thermodynamic of the adsorptive removal of the chloride ions from these two composites are investigated. According to the results obtained, the adsorptive removal of chloride ions is initially rapid, and the equilibrium time is reached after 30 min. The optimal pH value is 7.0 for a better adsorption, and the maximum capacity can be achieved, which is 60.2 mg/g with 1000 mg/L of the initial chloride concentration. The Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich adsorption models are applied to describe the equilibrium isotherms at different chloride concentrations. According to the equilibrium isotherms and the correlation coefficients (R2CDC: 0.9424, R2LDC: 0.996), the process can be described by the Langmuir model, and exhibits the highest removal rate of 97.24% (24.31 mg/g) with 250 mg/L of the initial chloride concentration. The pseudo-first-order and pseudo-second-order, intra-particle diffusion, and mass transfer kinetics models are used to identify the mechanism of the adsorptive removal of the chloride ions. The pseudo-second order model due the correlation coefficients (R2CDC: 0.9217-0.9852, R2LDC: 0.9227-0.9926) can be fitted to the kinetic calculations, and it is applicable for the adsorptive removal of chloride ions by the adsorbents. The thermodynamic calculations show that in a low chloride concentration, the sorption is spontaneous, associative, and endothermic; and in a high concentration, it is unspontaneous, dissociative, and endothermic. The calculated value of free energy (E) for adsorption onto the adsorbents suggests that the reaction rate controls the adsorptive removal of the chloride process rather than diffusion. It can be concluded that these two composites can be used as effective and applicable adsorbents for the adsorptive removal of chloride ions.
