نشریه مهندسی منابع معدنی
سال هفتم شماره 2 (تابستان 1401)

The Esfordi 1:100,000 geological sheet is situated at the Bafgh-Posht-e-Badam district in the central Iran structural zone. Due to the high mineral potentials in this region, many studies have been dedicated to investigate geological phenomena and seek minerals such as iron, phosphorus, lead and zinc. The present study attempts to delimit and explore new mineral potential zones in the Esfordi area through several satellite imagery data. Whereby three types of satellite imagery data including, Sentinel-2, Landsat-8 and ASTER, have been incorporated in this analysis to provide more reliable and powerful outputs. The processing algorithms such as band ratio, false color composites, principal component analysis and directional filtering were used to extract geospatial ore-bearing indicators. Note that areas covered by iron oxides were identified from the band ratios of Sentinel-2 and Landsat-8 images. Based on the color composite images, the rock units that have more impact on mineralization zones were separated. To map alteration zones in association with iron oxides, selective hybrid principal component analysis of bands from ASTER sensor and sentinel-2 satellite data was utilized. By employing directional filtering on the Sentinel-2 images, lineaments were extracted. In addition, prediction-area (P-A) plot was used to determine the weight of each alteration layer and lineament in identifying mineralization zones. The results show that the argillic and propylitic alterations have the lowest association with the mineralization, meanwhile the phyllic alteration with the highest weight has played a significant role in introducing mineralized zones. Outputs show that the mineralization in the study area is mainly related to rhyolite, rhyodacite and carbonate rocks.

The diversity of exploration data and the cost of borehole drilling necessitate the use of a suitable integration method for the analysis of the data of the semi-detailed exploration stage. In this paper, two hybrid multi-criteria decision-making algorithms, namely CCSD-EDAS and CCSD-MARCOS, are introduced. The data of Khoynaroud exploration area, in East Azerbaijan province, has been used to investigate the performance of these algorithms. The spatial data layers used include four geochemical, two geophysical and two geological layers in an area of 1400×2100 meters. The integration results show that the map obtained from the CCSD-EDAS algorithm has samples with weights approximately close to each other and above, while in the CCSD-MARCOS algorithm, the samples have more reasonable weights. The R statistics of the permutation method also show the relative superiority of the results obtained of the CCSD-MARCOS algorithm. The integration results show four potential mineralization zones in the study area. Zones I and II have the possibility of copper-gold porphyry mineralization and Zones III and IV have the possibility of mineralization of quartz-gold veins. Zone I, with an area of 400 × 1200 meters, has been proposed as the best zone for drilling network design. Also, the use of these two hybrid methods, especially the CCSD-MARCOS hybrid multi-criteria decision-making method, for integrating the exploration data is the most important suggestion of this paper.

Reliable and accurate determination of water saturation above the oil-water contact of the hydrocarbon-bearing formations is essential for calculating hydrocarbon in place. In this study, water saturations were measured directly from 160 core samples by Dean-stark test in one well and thin sections have been used to identify geological properties. Archie coefficients were also determined on plug samples. The water saturation values obtained from the electrical models including Archie, Waxman-Smith, and dual water were measured in Geolog7 software and applied in Kangan and Dalan formations in one of the fields in the Central Persian Gulf. In this study, four methods have been used to determine the rock types, including Winland, reservoir quality index, pore type, and depositional texture to identify the parameters affecting the distribution of water saturation. Results showed that pore throat radius is a parameter that affects water saturation and this parameter is directly related to the increased permeability and reduction of the difference between the water saturation values of Archie with the Dean-stark test. Determination of rock types based on depositional texture and pore type revealed that the cement type and texture and the pore types, control the permeability and distribution of water saturation in the reservoir. It was also found that depositional texture, unlike pore throat radius, well separates sedimentary environments. The results of water saturation calculations showed that if the Archie coefficients are calculated in each flow unit, the water saturation resulting from it would be very close to the water saturation values in the core (Dean-Stark). The electrical model of water saturation, with different coefficients in samples with different reservoir quality index or pore types, yields the most accurate water saturation values compared to Dean-Stark.

Potential field methods, such as the gravity technique, have become essential tools for exploration. Inversion of gravity data is the most important stage in the interpretation of the data. Inversion is a mathematical technique that constructs a geophysical subsurface model automatically from measured data by adding some prior knowledge. Inversion of gravity data is time-consuming and needs a long time because of numerous data and model parameters. Thus, a fast and effective inversion method is necessary to improve the speed of the inversion process. Many algorithms are available for focusing inversion of gravity data, such as the reweighted regularized conjugate gradient (RRCG) method. This method is iterative, and it takes a long time to converge to a solution. In this algorithm, there is a conjugate gradient parameter that is effective in inversion. In this paper, we used a hybrid conjugate gradient parameter method for focusing inversion of gravity data and compared the results with the conventional Fletcher-Reeves (FR) conjugate gradient parameter method. We applied this method for the data from a synthetic model and Shoaz iron ore deposit in Yazd, Iran. The inversion result indicated that the hybrid conjugate gradient parameter method converges to the solution faster than the FR method, while the results from both approaches have remarkable correlations with the true geological structures.

Concrete is the most widely used material in mining and civil projects and its mix design must be based on application, type of material and environmental conditions. In this study the effect of combined glass and polypropylene fibers on physical and mechanical properties of concrete and cement mortar was investigated. Nowadays, artificial fibers are used to improve the mechanical properties of concrete. Particularly, glass, polypropylene, carbon and steel fibers used in concrete lead to good results in improving its several properties. To this purpose, the concrete and cement mortar samples were made without fiber, with individual glass fibers (0.2, 0.35 and 0.5 volume percent of concrete or cement mortar), with individual polypropylene fibers (0.2, 0.35 and 0.5 volume polypropylene fibers 0.17 volume percent and glass fibers 0.18 volume percent of concrete or cement mortarpercent of concrete or cement mortar), and with combined glass and polypropylene fibers (). The physical properties including effective porosity, longitudinal waves velocity and the mechanical properties including Brazilian tensile strength and uniaxial compressive strength of the samples were analyzed. The results indicated that the effective porosity of concrete and cement mortar with combined glass and polypropylene fibers was less compared to the concrete and the cement mortar without fiber, with individual glass fibers and with individual polypropylene fibers. The velocity of longitudinal waves, tensile strength and uniaxial compressive strength of the concrete and the cement mortar samples with combined glass and polypropylene fibers were higher than the other samples. Compared to the concrete and the cement mortar samples without fibers, the tensile strength of the concrete and the cement mortar with combined glass and polypropylene fibers were increased by 15.22% and 16.44%, respectively, and their uniaxial compressive strength showed the increase of 27.3% and 20.56%, respectively.

The first production cycle in open-pit mines is the drilling of blast holes, which is a major part of the exploitation costs. Bits are considered as one of the most important parts of drilling in operational processes due to the type of application and high costs. Examining the parameters affecting the bits wear can reduce the effect of wear, prevent wasting time and additional costs of the drilling process. Therefore, in this study, first, by determining the effective parameters based on the results of univariate regression and Principal Component Analysis (PCA), the relationship between these factors and the tricone rotary bits wear has been determined through statistical methods. Then, 100 linear and nonlinear models were examined to predict the rate of the tricone rotary bits wears during drilling, of which only 21 models, including 6 linear models and 15 nonlinear models, were approved. The performance of these models is evaluated based on the root mean square error (RMSE), coefficient of determination (R2), Variance accounted for (VAF), and mean absolute percentage error (MAPE). then the priority of each method is determined based on performance evaluation and prioritization strategies. In this research, three strategies of prioritization, the Rank average method, the Borda method, the Copeland method, and finally the Aggregate of these methods have been used. The ranking results show that the best model for predicting the tricone rotary bits wear is the regression model with independent variables of Weight on Bits (WOB), Uniaxial Compressive Strength (UCS), and Geological Strength Index (GSI). According to the results of sensitivity analysis, the Rij value of the Weight on Bits (WOB) is 0.982, which is more than the other two parameters of the final model. Therefore, this parameter has the greatest effect on the tricone rotary bits wear and it is the most important parameter of the final model.

Galvanic interaction between sulphide minerals and grinding media has a pronounced impact on grinding (in terms of wear rate of balls and liners, energy consumption, product size and throughput) and flotation (in terms of surface products formed which affect mineral hydrophobicity) performance. The main objective of the current research study is to investigate the influence of electrochemical control on grinding and flotation performance. Laboratory tests were carried out on a representative sample taken from the Miduk copper concentrator plant feed under controlled electrochemical conditions. Laboratory grinding tests with different grinding media indicated that chromium balls not only resulted in the reduced grinding media wear in the mill, but also led to the improved flotation performance.The mass wear rate of steel balls was found to be 1.68 times of high-chromium balls. This is related to more oxidizing and alkaline conditions with higher oxygen concentrations in the presence of high-chromium balls. Addition of lime in the mill caused more oxidizing conditions (increasing the pulp Eh from 55.91 mV to 189.79 mV) with higher oxygen content (increasing the pulp DO from 2.44 ppm to 6.39 ppm) of the pulp which eventually resulted in higher flotation grade and recovery. Maximum copper recovery was observed when xanthate (Z11) and thionocarbamate (X231) collectors were added to the flotation cell, while the highest selectivity was achieved when the both collectors were fed directly into the mill. The more reducing grinding conditions and lower oxygen content of the pulp was related to oxidation of xanthate to dixanthogen when it was added into the mill.

Load movement in tumbling mills involving spherical particles has been extensively studied with the discrete element method (DEM) in the past. This assumption is legitimized by the added complexity of non-spherical shape representation, contact detection and computational cost. Simulation of particles with realistic shape helps to capture the essential aspects of mechanical behavior of the particulate material. In this research, an in-house developed DEM software called KMPCDEM© was used to simulate the charge movement with spherical and non-spherical particles. At the first to calibrate the model parameters, a model tumbling mill (100 cm diameter and 10.8 cm length) with one transparent end was used. The tests were performed with steel balls and wood cubes. After calibration, a number of mill simulations were performed with the different shape of particles (spherical, cubical, and tetrahedron) to study the effect of particle shape. Comparison of the simulation and experimental results showed that the difference between the measured and predicted impact toe, shoulder angle and bulk toe angles were within 3˚-5˚ of the measured values in the model mill. The amount of in-flight of charge when using spherical and non-spherical particles was significantly different (17%). The marked difference was attributed to higher interlocking of non-spherical particles in comparison to spherical balls. The results showed that the elongation of charge was increased (5o) by considering the non-spherical shape of particles. The simulation computation time increased by 35 times when the shape of particles changed from spherical to cubical.

The process of recovering metals from spent lithium-ion batteries is difficult due to the complexity of the metal components. Therefore, the separation and extraction of metal ions from the leaching solution of spent lithium-ion batteries requires a set of hydrometallurgical processes. In this research, precipitation and solvent extraction processes have been used to the final recovery of metals. Initially, 96.5% of manganese ions were precipitated by applying potassium permanganate with the molar ratio of manganese ions to potassium permanganate: 2 and pH: 2. Then, via dimethylglyoxime in molar ratio of nickel ions to dimethylglyoxime: 0.5, and pH: 5, 96% nickel recovered, approximately. Subsequently, using 30 v/v% D2EHPA and 5 v/v% TBP respectively as an extractant and a modifier of the organic phase, and under optimal conditions of Vo/Va: 1, pH: 5, temperature 25 ºC, time 20 min and mixing speed 400 rpm, it is possible to achieve 93.38% cobalt extraction efficiency and also control the loss of lithium at 16.74%. Finally, in the molar ratio of lithium ions to sodium carbonate: 0.7, temperature 100 ºC, time 40 min, mixing speed 400 rpm and the pH: 12, the lithium precipitation efficiency reached to 98.84%.

Froth stability is of particular importance and  has a significant impact on the flotation process. Froth stability can be defined based on the formation of froth (maximum froth height or froth retention time) or the froth decay (froth half-life). Froth stability is influenced by various factors such as the superficial air velocity (Jg), the collector dosage (CC), frother dosage (FC) and the sample particle size (d50). In this work the effects of these factors were examined. The results showed that increasing the Jg, the CC and the FC will increae the froth stability. For example, by increasing the FC from 60 to 140 g/liter, the froth retention time (FRT) and the half-life froth (t1/2) increased by 92% and 71%, respectively. Sample particle size behaved differently in froth formation and decay, so that by reducing the d50, the froth retention time increased but the froth half-life decreased.