نشریه مهندسی منابع معدنی
سال سوم شماره 3 (پاییز 1397)

In this research, we have used ASTER-Terra satellite images were used for spatial analysis of Abgarm geothermal basin to study travertine formation of the north west of Qazvin. All Synthetic photo-maps generated with band Ratios and PCA applied in images for introducing the location of hydrothermal alterations. Remotely sensed evidences indicate the patches of iron oxides and hydroxides mineral facies in aggregation with clayey minerals as a common mineralization sequence in hydrothermal environment. Many of geological features and Aster- sets such as faults, lineaments and multispectral images have been used and processed for potential mapping of Abgarm mineralization with focuses on formation of solution-related Travertines locations as well as preparing a Fuzzy-based prognostic map for exploration. As a rule, in the membership functions, many of weighted variables were used before scoring them according to spatial data modeler algorithms applied in lithological evidences (on the basis of diversities in sexes and ages) as well as weighting the structures (on the basis of densities). Also, all evidences were integrated with changes in geological formations according to “And” operator applied. Our innovative results not only represented several patterns of the hidden structures but indicated their associations with spatially altered formations. Moreover, a fuzzy-based gamma operator was used for final mapping of Abgarm Travertines based on our future plan for geochemical explorations.

Determining the position of potential field anomalies is one of the objectives of data processing, which is done using various methods such as normalized full gradient. The normalized full gradient method used in the interpretation of geophysical data is a semi - quantitative and semi - automatic method, which incorporates Fourier transform for the elimination of the problems associated with the application of the downward continuation filter through an anomalous source. The results will be reliable if the number of harmonics in the Fourier series is used correctly. The enhanced normalized full gradient method analyzes the two curves: the energy ratio curve of the reconstructed anomalies and the depth curve, along with variation in the number of harmonics, and provides a suitable solution for selecting the number of optimal harmonics. This method was applied on synthetic models and satisfactory results were obtained. The enhanced normalized full gradient method has also been used to determine the position of the anomalous body of Jalalabad deposit. The result of this study shows that using the enhanced normalized full gradient method it is possible to determine the number of optimal harmonics and the position of anomalous bodies from potential field anomalies.

Oil price is the most important and effective economic parameter during the course of oil projects evaluation process. Oil price uncertainty is affected by some factors such as political issues, supply and demand, advancement of technology etc. Therefore, evaluating an oil project is unreliable unless these uncertainties are taken into account and in some circumstances, not doing so may mislead the oil projects evaluators, managers and shareholders. To solve this problem, many researchers have tried to present intelligent models for estimating oil prices using fuzzy logic, neural networks, etc. In addition to their high accuracy, these methods gives easier and faster estimation. In the present study, taking the importance of the oil price prediction into account, OPEC crude oil data were collected weekly during 2013-2016, and some prediction models were presented using artificial neural network method, time series functions and binomial tree. Comparing the results obtained from the three models and those of the real data showed that the estimation made by neural network method is much more reliable.

Mining is regarded as one of the most polluting sources of environment due to the production of toxic acid wastewater. Considering the environmental impacts of mining in the stage of mine production planning development can potentially reduce the harmful effects of this industry on the environment. In this research, attentions have been paid to the planning of production in Sungun Copper mine looking at parameters and environmental impacts. For this propose, field studies were conducted and chemical analysis, as well as exploratory and mapping data for planning of environmental production have been carried out, and various sections of ore have been evaluated with a view of the production of waste water. After modeling the mineral deposit and providing a block model, toxic elements content was determined for each block using the Kriging method, and the weight and effect of the blocks were determined using the entropy method. The block model in contrast to conventional production planning methods that include only grade of minerals, considers the wastewater production capacity of each block and its degree of pollution. Finally, by designing a production planning based on the environmental impacts of the toxic elements prevailing in Sungun copper mine eight operational phases were designed for this deposit. In this planning, blocks in the first pitt with a mean pollution level of 1141 and those in the final pit with an average of 52 have been found to represent the highest and lowest potential, respectively, producing harmful wastewater into the environment.

High concentration of sulfate in acid mine drainage is one of a chemical pollutants which can cause various health problems and damage the wastewater piping systems if not enough attention is given to its removal. In this research, adsorption process was selected as an effective, simple and low-cost method for sulfate removal. The modification of clay minerals as a natural and eco-friendly adsorbent is very useful for improving their properties along with permanent porosity. In recent years, pillared clay has been received much attention. In this study, the structural properties of Al, Fe-pillared nano bentonite is improved by using the combined ultrasonic wave and microwave irradiation technology. In this adsorbent, the synthetic duration time and water consumtion are reduced and the number of active sites are increased. Therefore, an effective adsorbent is produced with high absorption capacity compared to the initial bentonite sample. In this study, the thermodynamic parameters was calculated by examining the effect of temperature, while the adsorption data are fitted by Freundlich, Langmuir and Temkin isotherm models. The thermodynamic results showed that the adsorption process for both initial and pillared bentonite were exothermic and spontaneous. Second-order kinetic models and intra-particle diffusion model demonstrated that the main adsorption mechanism was chemical absorption with penetration into the absorbent porous media, especially in the pillared sample.

Flotation is the most commonly used process for desulfurization of iron concentrates in iron beneficiation plants. The current study deals with improving the metallurgical performance of the flotation circuit at Sangan iron beneficiation plant. A plant survey indicated that sulfur content of iron concentrate is sometimes higher than that of the permitted limit used for the pelletizing plants (<0.25%). For this purpose, laboratory and full-scale experiments were carried out. In the batch flotation tests, the effect of collector dosage (65-105 g/t), frother dosage (45-75g/t), pH (6-10) and slurry solid content (27-33%) was examined against sulfur recovery. The results showed that the collector dosage, pH, frother dosage and slurry solids% are the most significant parameters in terms of sulfur recovery, respectively. The metallurgical performance improved with increasing the collector and frother dosage as well as reducing the pH. In the plant site tests, the influence of collector distribution method in the flotation circuit, collector dosage (65-105 g/t), frother dosage (37-85 g/t) and slurry solids% (25-33 g/t) on the flotation circuit performance was investigated. The results indicated that the optimum metallurgical performance was achieved when collector addition is divided into three parts: 50% was added to the rougher feed, 30% to the cleaner feed and 20% to the scavenger feed. Increasing the collector and frother dosage resulted in an increase in the sulfur recovery and a reduction in iron concentrate sulfur content. Increasing the slurry solids% was found to be beneficial to the sulfur recovery and detrimental to the quality of the product.

The overall flotation recovery depends on the recovery in the pulp zone as well as recovery in the froth zone. The froth retention time affects the froth recovery and it has an inverse relationship with both froth recovery and overall recovery. On the other hand, the froth retention time depends on gas rate and froth depth. The gas rate is an independent factor in induced-air flotation machines, whereas in self-aerated cells it depends on various variables and the froth depth is one of them with significant effect. Therefore, adjusting the gas rate is more complicated and more difficult in the induced-air flotation machine. This study attempts to investigate the effects of froth depth and gas rate on superficial gas velocity, froth retention time and metallurgical performance of the cell. The operation of these types of cells can be improved, by understanding the relationship between these parameters particularity the adjustment of froth depth and gas rate. Experimental tests were carried out in a 50 m3 self-aerated cell in Gol Gohar iron ore processing plant. The results showed that although the froth depth variations, changed the gas rate, but the gas rate variations did not have a significant effect on the froth retention time and the metallurgical performance. Also, the froth depth was not a good option to change the gas rate and the superficial gas velocity in this type of flotation cells, because the range of superficial gas velocity variations was low when the froth depth was changed in industrial-scale.