نشریه مهندسی منابع معدنی
سال هفتم شماره 3 (پاییز 1401)

Remanent magnetization is impossible to ignore in many applications of magnetic method including mineral exploration particularly iron ore, geomagnetism, regional investigation, and archaeological measurements. Magnetization vector inversion has made great attention in recent years since both distribution of the magnitude and direction of the magnetization have been obtained, therefore, it is easy to distinguish between different bodies especially when magnetic data are affected by remanent magnetization. In this research, the magnetization vector inversion (MVI) has presented: a 3D magnetic modelling is proposed from surface measurements to obtain magnetization distribution. The equations have solved in data-space least square to reduce computer memory requirements and speed up calculations. The algorithm has included the combination of three weights as depth weighting, distance weighting and compactness weighting in Cartesian direction. The method has been validated with a synthetic example including a dipping dyke and the results are acceptable compare with true magnetic anomaly.

The geostatistical method is one of the most advanced techniques to assess and survey groundwater quality.  Using unsuitable water results in some problems such as soil salinity, reduction of soil permeability, decrease in water absorption by plant roots, diminution of crop productivity, or even menace agricultural production. Accordingly, in this study, the groundwater quality in the study's area for agricultural uses as well as industrial applications by using common diagrams and components related to the classification of water quality was investigated. ISATIS and Surfur software were used to illustrate changes in quality characteristics in the study's area graphically and Consecutive Gaussian simulations to analyze spatial connection among variables and estimate some of the quality indexes such as PH, RSC, Na%, SAR, and Ec. After data normalization, the variogram was calculated, and a sufficient model was selected to fit the experimental variogram based on the lowest SSR Error. Afterward, Consecutive Gaussian simulation in 100 samples in the study's area was examined using the fitted model based on the experimental model, and the maps resulting through simulation in different thresholds were provided. The results showed that the majority of samples have fairly suitable quality in terms of SAR, and in general, they are appropriate for agricultural uses. Percentage risk of Sodium in agricultural water in the study's area was also classified into the appropriate class. Except for four samples whose spatial connection of the forgoing cases have been interpolated and the interpolated probability maps have been provided, the water quality for industrial uses is susceptible to sedimentation in all statutes.

Qalikouh area is located 35 km southwest of Aligudarz city, Lorestan province, SW of Iran. The area is located in the central part of the Zagros Geological Zone. The oil shales of the area are located in the Upper Triassic and Lower Jurassic of Sargalu and Garau Formations. The Sargalu Formation contains a series of shale, carbonate and clays. Garau Formation includes oil shale horizons with different thicknesses, ammonite shales and black cherty layer. In order to investigate the enrichment ratio and relationship between elements and organic matter, 53 samples of oil shale from Garau and Sargalu formations were selected. The samples were analyzed by XRD, XRF, ICP-MS and Rock-Eval analyzer. Data processing was performed using factor analysis, fractal modeling, stepwise factor analysis and principal component analysis. The data show that Sargalu Formation with average TOC = 13.27% and Garau Formation with average TOC = 18.13%, have high content of organic matter in central and NW of the area. Cconcentration-number fractal modeling showed that the Co, Mo, Ni, Pb and U have significant anomalies. The stepwise factor analysis (SFA) method showed a significant correlation between the anomalous elements and TOC. Geochemical maps showed that the anomalies are located for Co and Pb in the center and SE, for Mo, Ni in the NW and center, for V and REE in the NW, and for U in central part of the area.

In determining the optimal points of production drilling, it is important to identify areas of suitable reservoir quality. For this purpose, the use of geochemical data, which is usually small in number, is common. This data discontinuity creates information gaps. If one uses more continuous data so that its modeling accuracy is suitable, the drilling could be then performed with more success. In this study, seismic and well logs data were used to classify the quality of gas facies by two non-parametric statistical (Parzen) and supervised deep learning techniques (long-term short-term memory network (LSTM)). The LSTM network was then also optimized by two heuristic optimization methods (Imperialistic competition algorithm and Whale algorithm). The obtained results indicate that both methods produce good results in classification so that the modeling accuracy of gas facies quality using supervised deep learning technique (87%) is more than that of the non-parametric Parzen (83%) method. Moreover, the application of optimization algorithms has increased the classification accuracy. The best accuracy is related to the LSTM network optimized with the imperialistic competition algorithm (90%). Geochemical reports and well cores data show the high validity of these models.

Mines as non-renewable resources have a significant role in the economic and social development of countries. However, at the end of the mine's life, to achieve sustainable development, the mine's pits reclamation is vital. Due to the situation of most mines that are located in remote areas, mine's reclamation based on renewable energies can be an appropriate strategy. In this study, a new hybrid method using the Fuzzy Cognitive Mapping (FCM) method, grey Complex Proportional Assessment (COPRAS-G), and Z-theory reliability is introduced for prioritization and selecting of the mine's reclamation strategies. The proposed method, for reclamation of an open-pit lead-zinc mine by considering several criteria and strategies is applied. The results of the FCM show that the average wind speed criterion has the highest weight. Also, the prioritization of the strategies showed that "closing the mine and building wind turbines" is the best strategy for reclamation of the investigated mine. Therefore, considering the windy situations in the study area, building a wind farm to supply electricity is a suitable strategy to achieve sustainable development in the region.

Recent development in eXtended Finite Element Method (XFEM) opened new avenues thorough crack propagation problems. However, it ability to predict crack path in micro scale medium of a real porous rock is always questionable. In this work, numerical modeling of the effect of pore size on crack growth and comparison of the effect of different pore shapes and location has been developed using the finite element method to compare the maximum strength of reservoirs and complex rock models. The results showed that the equivalence of the main pores in the sample with simple geometric shapes such as circles, ellipses and angled shapes can well simulate the mechanical behavior of materials and crack growth in Phenomena such as hydraulic fracturing.

In the wastewater of many industrial plants and mining industries, there are halogen compounds such as chlorine, fluorine, bromine and iodine, which can redce the quality of recycled water. One way to remove halogenated anions from wastewaters is to use layered double hydroxides, which have several advantages such as simplicity and low price. In this study, the adsorption properties of layered double magnesium / aluminum hydroxide is investigated by laboratory studies and molecular modeling for fluoride to iodine halogens. Laboratory studies have been performed to compare the ability to absorb different types of halogens by synthetic magnesium aluminum LDH (original and calcinated at 400 ˚C) and molecular modeling studies to understand effective mechanisms for different halogenated anions. The results of laboratory studies showed that both original and calcinated layered magnesium / aluminum hydrochloride have the highest absorption potential for fluoride ions and the lowest absorption for iodide ions. Calcination significantly increases absorption for all types of halogens. The predominant mechanism for the uptake of halogenated anions by non calcinated layered double hydroxides is ion-exchange and in calcinated products, surface and physical absorption. The electronegativity seems to be the determining parameter. The results of the energy calculation of the interaction obtained from the molecular modeling show that the preferred position for all halogens is the hollow hexagonal structure of the double-layer hydroxide. Also, the absorption rate in the hollow hexagonal position is the highest for the fluorine and the lowest for iodine. In addition to confirming the results of laboratory studies, these modelling results confirm the possibility of using molecular modeling methods as a powerful tool in examining the behavior and understanding the process mechanisms.

Attention to the hardness of ores and their grindability is increasing due to the importance of energy consumption. In this study, 73 samples of iron ore were prepared from Gole-Gohar’s No. 1 mine, and the SAG power index test was performed to measure hardness. The distribution of the hardness values of these samples and its comparison with the results of the last five years showed a significant increase in the hardness of the mine so that the average hardness increased from 32.1 minutes to 65.6 minutes. In addition, the hardness distribution of Gole-Gohar mine demonstrated that 52%, 26%, and 22% of the ore were obtained with a hardness of less than 50 minutes (soft materials), 50-100 minutes (medium), and more than 100 minutes (hard), respectively. Among the hardness-related parameters, the total Fe, S, Fe/FeO ratio, density, and magnetite recovery in the Davis tube test had no significant relationship with hardness, indicating the special importance of homogenizing the feed to the processing plant based on ore hardness in addition to grade homogenization. However, mineralogical factors such as texture, the composition of the constituent minerals, and the type and frequency of the constituent minerals have a significant effect on the hardness of the samples.