نشریه مهندسی منابع معدنی
سال هشتم شماره 1 (بهار 1402)

Drilling fluid properties and determination of its appropriate formulation are very important for the success of drilling operations. In this study, the effect of hydrophilic silicon oxide nanoparticles and iron oxide in combination with polyacrylamide on the rheological and filteration properties of water-based drilling mud was investigated. Silica and iron oxide have been used as nanomaterials due to their abundance and economical advantages. Material characterization was performed using X-ray diffraction analysis (XRD), scanning electron microscope (SEM), and Fourier Transform Infrared Spectroscopy (FTIR). Rheological properties including plastic viscosity and gel strength were measured at different concentrations of polymer and nanoparticles. Moreover, the effect of additives on the mud filtrate and mud cake quality was evaluated. The results showed that the presence of silicon oxide nanoparticles can improve the rheology of drilling mud up to 15% at a concentration of 1 wt %. The viscosity increased due to the separation and dispersion of clay plates.  Furthermore, the results indicated that the addition of iron oxide nanoparticles did not have a significant effect on rheology. On the other hand, the addition of polymer caused a significant increase in viscosity and gel strength of drilling mud. The obtained results showed that due to the interaction of clay plates with silica nanoparticles, the gelatinous properties of drilling mud decrease at low concentrations of nanoparticles. The results of the filtration test showed that the addition of polymer and nanoparticles to the drilling mud causes a further decrease in the filtration rate at lower concentrations of the polymer. This effect is due to the clogging of mud cake pores by nanoparticles in the presence of polymer, so that with the simultaneous addition of nanoparticles and polymer, the mud filtrate was decreased from 128 cc to 14 cc.

Separating hydrothermal alteration zones is a main challenge in remote sensing science. The results showed that application of conventional methods based on spectral properties could not exactly separate hydrothermal alterations. Therefore, this research attempted to identify hydrothermal alteration zones in the study area by combining principal component analysis and concentration-area fractal model. The developed model was evaluated by confusion matrix, commission and omission error and total accuracy. The commission and omission error of phyllic zone is 4.51 and 9.13 percent, respectively, and the omission error of argillic zone is equal to 54.16 percent. The results indicated that concentration-area fractal model is able to identify phyllic, argillic and propylitic zones in the study area. Because of the same spectral signature of phyllic and argillic minerals, the concentration-area fractal model could not exactly discriminate these two alteration zones.

In the current research, the buried causative body of a magnetic field anomaly was modeled using Encom ModelVision software and its depth was estimated using deconvolution Euler and energy power spectrum methods. The magnetic data of Iileh region of Taybad city was used for modeling. In addition, an optimization algorithm was explained as the Improved Global Particle Swarm Optimization (IGPSO). The obtained results showed IGPSO is acceptably resistant to the corrupted synthetic gravity data by noise. Using this optimization algorithm, the pseudo-gravity data of Iileh region was analyzed to determine the structural parameters of the causative body of the anomaly such as depth, radius, density contrast, origin point coordinate and shape factor. The determined shape of the causative body of the anomaly was a sphere with a radius of 56.2 m and a density contrast of 1.93 gr/cm3. The estimated depths of the center of the sphere by Encom ModelVision software and IGPSO method were 120 m and 111.8 m, respectively. While the drilling results in this area shows an average depth of 103.2 m for the center of the iron mineral body. This indicates the introduced IGPSO method obtained better results.

Loading and hauling operations have the highest share of the production costs of open-pit mines. Therefore, in choosing the loading and hauling machines, paying attention to the economic aspects is necessary. For a better understanding of the financial performance of mining machinery, various performance indicators have been proposed by researchers. This research presents a special form of economic performance index, which indicates the ratio of each machine's revenue to its total cost. For this purpose, the cost and revenue of the transport fleet, including dump trucks, mining shovels, and backhoe excavators, were collected for two years (From September 2017 to September 2019) and determined. As the first step, the total cost and the amount of revenue from the operation of each machine then, the Economic Performance Index (EPI) for each of the loading and hauling machines is calculated and compared with each other. The results show that Backhoe excavators perform better than mining shovels. In addition, by examining different trucks from different manufacturers, it was found that C100 series trucks have the best performance among all trucks. Its average economic performance index value for each of those trucks is 2.82.

The application of new technologies has a significant effect on increasing the efficiency and improving the productivity of production factors in various industries, such as the mining industry. This requires implementing correct and practical strategies, and any incorrect procedure can cause companies and businesses to waste resources. Accordingly, the main aim of this study is to determine attractive strategies for the use of so-called fourth-generation technologies (industry 4.0) in the mining sector of Iran. To do this, a multi-criteria decision-making (MCDM) problem was employed. Therefore, this study presents a new method for evaluating and prioritizing smart mine strategies using a combination of Z-number theory and fuzzy weighted VIKOR technique with a fuzzy cognitive map (FCM). In this regard, questionnaires containing five strategies (options) and 11 criteria were designed and presented to a team of eight experts. The results obtained from the prioritization of the proposed hybrid model confirm that the strategy of "provision of government incentives to mines to use up-to-date technologies" is the most appropriate alternative for implementing industries 4.0 in large-scale mines in Iran. Furthermore, a parametric sensitivity analysis was performed to determine the effectiveness of the proposed strategies. Results showed that the proposed strategy is a fixed mechanism for ranking smart mining engineering strategies. Meanwhile, the weight of the strategy does not affect their ranking.

Nowadays, duo to mining and construction activities' progression, the need to utilize blasting has been increasing in order to reduce time and cost. The use of blast for drilling and crushing rock, in addition to its advantages, has disadvantages, the most important of which is ground vibration. Vibration caused by the blast is an important and significant part of the blast process and controling its amount in order to reduce possible damage to the surrounding areas, is always necessary. In this paper, the field data of the blast in the second line of the Tabriz water pipeline project have been collected using three-component Blast Recorder seismographs. By modeling the process of blast in ANSYS-Autodyn finite element software, the behavior of the blast zone environment is simulated. The average of numerical modeling errors compared to field surveys is estimated at about 20%. According to the numerical modeling, the most critical state of velocity entering the pipeline is less than the allowable blast standards near the pipeline, and the maximum stress, strain, and displacement in the boundary of pipe and soil are equal to 17.24 MPa, 135 μmm /mm, and 0.18 mm, respectively.

In the basic metals market, copper and aluminum are among the most popular metals in manufacturing and construction industries due to their uses in various industries. Given Iran's favorable rank in the production and export of copper and aluminum in the region, this study had investigated the factors affecting on their global prices in the short and long-term. Therefore, in the current research, an attempt has been made to investigate the short-term (with emphasis on the spillover effect) and long-term influencing factors on the prices of these two important metals using DECO-GARCH and NARDL models. According to the results of the DECO-GARCH model, in the short term, the price of oil, parallel metal markets such as nickel, alumina, and the dollar index with the stock index have a significant effect on the global prices of copper and aluminum. Also the existence of the spillover effect among them was confirmed. According to the results of the short-term model, the existence of the spillover effect in the models was confirmed. In fact, any fluctuation in any of the variables instantly affects the fluctuations of other variables. According to the results of the long-term model, oil price, economic growth, technological changes, industrial production index, prices of metals such as nickel and alumina, stock index, and automobile production index have a significant effect on the global prices of copper and aluminum.

The printed circuit boards of mobile phones contain precious metals such as gold, platinum, and palladium, with 542, 30, and 26 ppm, respectively, and among the available base metals, copper constitutes the highest weight percentage (30.675%). Therefore, the recycling of this waste is very important not only from an environmental point of view but also from an economic point of view. the leaching operation, was performed, on the original sample printed circuit boards of mobile phones and cakes obtained from leaching with sulfuric acid by the amino acid L-valine and the effect of parameters such as L-valine concentration, temperature, pH, time, the oxidizing amount, the pulp density on the gold recovery was investigated and compared. The results showed that the parameters of temperature, leaching time, pH, relative to pulp density, L-valine concentration, and the amount of oxidant are more important in gold recovery, respectively. Recovery of gold leaching with L-valine amino acid under optimal conditions of L-valine concentration of 200 g/t, temperature 80 °C, pulp density 10%, oxidizing amount of 50 ml/l, pH 11.5, and leaching time 32 hours on the original sample and the cake obtained from leaching with sulfuric acid were 62.23% and 87.34%, respectively. In other words, by acid leaching with sulfuric acid before leaching with amino acid L-valine, the recovery of gold leaching by L-valine increases by about 25.11%.