 Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
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- Spatially weighted singularity mapping in conjunction with random forest
algorithm for mineral prospectivity modeling
Abstract: Geochemical exploration data play a vital role in mineral prospectivity modeling (MPM) for discovering unknown mineral deposits. In this study, the improved spatially weighted singularity mapping (SWSM) method is used to improve the practice of identifying geochemical anomalies related to copper mineralization in the Sarduiyeh district, Iran. Then, the random forest algorithm (RF) and geometric average function (GA) are used to integrate the resulting geochemical predictor map with other predictor maps. As demonstrated by the high area under the curve (AUC) values, this approach can effectively delineate prospective areas with RF and GA. However, compared to the GA approach (AUC=0.78), the RF technique (AUC=0.98) offers superior prediction capabilities due to its enhanced ability to capture the spatial correlations between predictive maps and known mineral deposits. The proposed procedure, a hybrid of the improved SWSM, RF has outstanding predictive capabilities with concerning for identifying prospective areas. A case in point is the new, highly prospective areas identified in this study, which present priority targets for future exploration in the Sarduiyeh district.
- Delineation of mineral potential zone using U-statistic method in
processing satellite remote sensing images
Abstract: Delineating and mapping alteration zones in porphyry copper exploration is of special importance. In this study, satellite image processing techniques were employed to highlight alteration zones in the Zafarghand exploration area. The Zafarghand area is located in the southeastern part of Ardestan and northwestern part of Isfahan. It is situated within the geological structural zones of central Iran and the intermediate magmatic arc of Urmia-Dokhtar. Various alteration haloes are present in this area, including phyllic, potassic, propylitic, argillic, and slightly siliceous alterations. In this study, the detection of related alterations was carried out using ASTER sensor imagery. Accordingly, considering the raster nature and digital form of satellite images, the digital number values of each pixel from the image matrices were considered as samples in a systematic network. Finally, the U spatial statistic algorithm was implemented as a moving window algorithm for determining anomaly samples in the set of digital number (DN) values of ASTER satellite image pixels. The results of this technique show that the application of the U statistic method, considering its structural nature and neighboring samples in decision-making, has been successful and has proven to be very effective in determining the alteration zones in the Zafarghand area. So that, could be observed the delineated the propylitic alteration by U-statistic method is closely associated with the defined zone of propylitic alteration, which is also consistent with the field and microscopic observation of the porphyry Cu mineralization in this alteration zone. It is also observed that the determined phyllic alteration by this image processing is spatially conformable with the sericitic alteration presented in alteration map (based on field observations and geochemical sampling).
- Rock Typing and Reservoir Zonation of the Asmari Formation in a gas field,
Persian Gulf
Abstract: In this study, geological and petrophysical methods were combined to investigate the reservoir characteristics of the Asmari Formation in one of the gas fields in the Persian Gulf. The key focus of this study is to categorize rock types and define reservoir zonation. Initially, sedimentary facies were identified through the analysis of core samples and the petrographic studies. Subsequently, the depositional environments of each facies were analyzed. After assessing the reservoir quality of sedimentary facies, various rock typing methods, including FZI, R35, and Lucia methods, were used to categorize the reservoir rocks. Finally, reservoir zonation was carried out based on the integration of information and the NCRQI method.According to these studies, the Asmari Formation in the studied field consists of ten sedimentary facies deposited in a carbonate ramp environment during the Rupelian and Chattian stages. From the perspective of frequency, coralgal reef facies play a significant role in this platform, while from a reservoir standpoint, the thin-bedded ooid grainstones are the least important reservoir facies. The high variability in porosity and permeability data for each facies indicates the importance of diagenetic changes in reservoir quality and porosity distribution. A comparative analysis of rock typing methods revealed that the reservoir rock is composed of five reservoir rock types, associated with different sedimentary facies, pore sizes, and reservoir properties. Finally, based on the integration of geological and petrophysical information, the reservoir rock was divided into five reservoir zones, with Reservoir zones As-2 and As-4 being the most important due to their relatively high porosity and permeability.
- Incorporating grade uncertainty into open-pit long-term production
planning using loss and profit functions
Abstract: Long-term production planning for open-pit mines is recognised as one of the vital decision-making issues in open-pit mining operations. In addition, the ore grade is one of the most significant sources of uncertainty in a mining operation, as it classified run-of-mine material into ore and waste. In the classical approach, the destination of mining blocks is determined by comparing the estimated grade with a pre-determined cut-off grade. However, the uncertainty of material grade dramatically affects production planning. In this paper, a novel model was developed based on the idea of simulating the grade to incorporate the risk of grade uncertainty. In the proposed model, the economic consequences of the assigned destination are calculated using the profit and loss functions and they are integrated with the production scheduling. The proposed production planning was implemented in an iron ore mine, and the results were discussed for classical, loss, and profit models. Results show that the net present value increases by 3.64% by implementing the profit function. In contrast, the loss function method reduces the net present value by 2.23% compared to the classic model. This happens because the amount of ore class is increased by 7.46% by the profit function method and decreased by 2.49% using the loss function method. Additionally, the coefficient of variation, as an index of uncertainty, was investigated. The results show that the loss function approach attempts to extract more reliable blocks in the early years and postpone the high-uncertain blocks to the later years of the production.
- Application of Bipolar Electrochemistry to Follow Electrochemical
Reactions at the Semiconductor-Electrolyte Interface
Abstract: The properties of the metallic minerals and the metallic minerals-electrolyte interface have always been a concern in the induced polarization (IP) geophysical method due to their effects on the IP response. Electrochemical reactions, if carried out, affect the interface characteristics. Hence, the occurrence of the reactions and their effects on the IP signal have been modeled through recent research, but they are not well known yet. While identifying these matters can help to create more realistic physical and petrophysical models, in order to better explanation of IP effects. So, in the present study, eleven metallic mineral samples and the laboratory method named bipolar electrochemistry, which we introduce for the first time to the IP research field, have been used to show performing the electrochemical reactions at the interface and the effect of various metallic minerals on them. The results showed that if the applied external electric potential is high enough, electrochemical reactions are carried out at the metallic minerals-electrolyte interface. In this study, these reactions were electrolysis of water and were carried out in all minerals (except sphalerite). However, the potential required to initiate the reactions was different for different minerals. The lack of water electrolysis reaction on the surface of sphalerite can probably attributed to its non-conductivity. On the other hand, the external potential responsible for the interface reactions was linearly linked to the potential difference between the two sample’s extremities. Considering the different potentials required to start the reactions in various samples-electrolyte interfaces, and the absence of these reactions in the case of sphalerite samples, it can be concluded that the samples’ compounds affect the reactions and their commencing potentials. So, we believe by studying these reactions, some properties of the metallic minerals can be achieved. Identifying the minerals’ properties and the reactions that can occur at their surfaces is essential for a detailed understanding of the factors affecting the IP phenomenon. To do this, we found using bipolar electrochemistry as an appropriate way.
- Predicting gold grade by using support vector machine and neural network
to generate an evidence layer for 3D prospectivity analysis
Abstract: This paper uses a support vector machine (SVM), back propagation neural network (BPNN), and multivariate regression analysis (MLA) methods to predict the gold in the Dalli deposit in the central province of Iran. Based on the results of the data analysis, the dataset was prepared. Then according to comprehensive statistical analyses, Au was chosen as an output element modeling, while Cu, Al, Ca, Fe, Ti, and Zn were input parameters. Then, the dataset was divided into two groups training and testing datasets. For this purpose, 70% of the datasets were randomly entered into the data process, and the rest of the data were assigned to the test of the procedure. The correlation coefficients for SVM, BPNN, and MLA were 94%, 75%, and 68%, respectively. A comparison of the correlation coefficients revealed that all used methods could successfully predict the actual grade of Au. However, SVM was more reliable and more accurate than other methods. Considering the sensitivity of the gold data and the small number in the exploratory database, the results of this research are used to prepare the main layer in the mineral prospectivity mapping (MPM) of gold in 2 and 3D.
- Development of mineralogy-based approaches to study the loss of copper
minerals into tailings of scavenger flotation circuit – Part I
Abstract: Loss of copper minerals to tailings of the rougher and scavenger circuits is one of the challenges in copper concentration plants, which reduces the efficiency of the circuit. The goal of this research is to utilize mineralogy-based techniques to identify the cause of the loss of copper minerals to tailings of the scavenger circuit. Process mineralogy studies have been performed on the scavenger of the flotation circuit - the Sungun copper concentration plant (located in northwestern of Iran). First, the feed, final concentrate, and tailing, as well as the concentrate and tailing flows of each of the scavenger circuit cells were sampled at different time intervals. Then, chemical composition analysis, laser particle size distribution analysis, and optical microscopy studies were performed on them. According to the results, the presence and changes in the abundance of copper oxide minerals, which make up about 45% of copper minerals, is one of the main reasons for the copper loss to tailings. Also, fine-grained particles of copper sulfide minerals (d80~45 µm), and the interlocking of copper sulfide minerals, especially chalcopyrite, with pyrite and gangue minerals (silicate), are among the most important causes of increased copper grade in the scavenger circuit tailings. In addition, the malfunction of the scavenger circuit cells due to the simultaneous presence of sulfide and oxide minerals and their fineness is another cause of the lost to tailings.
- Copper recovery improvement by reducing the misreported copper minerals
into the tailings of scavenger flotation circuit – Part II
Abstract: Loss of copper minerals into the tailings of the rougher and scavenger circuits is one of the challenges in copper processing plants, which reduces the efficiency of the circuit. In part I of the this paper, the causes of loss of copper minerals in the scavenger circuit tailings of the Sungun copper concentration plant (located in northwestern Iran) were determined. Changes in feed composition (ratio of copper oxide and sulfide minerals) and mineralogical properties of the input feed to the scavenger circuit have been the most important factors in the loss of copper minerals into the tailings. Accordingly, the purpose of present paper (part II) is to optimize the scavenger circuit by providing a solution to prevent the loss of copper minerals to the tailings. The feed, concentrate, and final tailings as well as the tailings of each of the scavenger circuit cells were sampled and then comminution and flotation tests were performed on each of them. According to the results, due to the high grade of copper in the scavenger circuit tailings (compared to copper grade in the tailings of the rougher circuit); via directing the scavenger circuit tailings to the input of the rougher cells, the recovery of circuit can be increased by more than 4%. Another solution to increase total recovery is to use a combination of sulfide and oxide collectors as well as sulfidation to float the copper oxide minerals in the scavenger circuit; in this way, the overall recovery of the circuit has increased by more than 11%. On the other hand, due to the loss of fine particles of copper minerals from the cells of the scavenger circuit, changing the size of the air bubbles to capture the fine particles can be an effective way to increase recovery. Also, a change in the grinding circuit to liberate the minerals involved in the feed of the scavenger circuit (most of which are the concentrate of the scavenger circuit itself) can lead to an increase of about 5% in the recovery of the circuit. Given the mineralogical characteristics of the scavenger circuit feed (which is the tailings of the cleaner cells), via applying changes in the operating conditions of the cleaner circuit which include the application of hybrid bubbles (Nano and coarse bubbles) as well as sulfide and oxide collectors, the resulting recovery of fine particles of copper minerals and copper oxide minerals to the cleaner concentrate will have a significant effect on the improvement of the performance of the scavenger circuit.
- Hydrocarbon Potential Evaluation in the Low Resistivity Pays (LRP) of
Sarvak formation with combining Nuclear Magnetic Resonance (NMR) and
Seismic data, one of the Hydrocarbon reservoirs in Southwest of Iran
Abstract: The objective of petrophysical studies is to assess the quality of hydrocarbon reservoir layers and to zone the reservoir for identifying optimal zones for exploitation and informed development of oil fields. In some regions, there are zones that exhibit lower electrical resistivity values than their actual values. These low-resistivity zones are often identified through petrophysical investigations and conventional well logs, where water saturation levels are estimated higher due to their reduced resistivity. These zones, despite their hydrocarbon potential, are often neglected during production cycles. To overcome this challenge, nuclear magnetic resonance (NMR) logging tools can be employed to provide accurate estimations of free fluid saturation, irreducible fluid saturation, permeability, and effective porosity in such low-resistivity zones, making them more identifiable.In this article, we utilized conventional well logs and NMR log from the A well in the Sarvak reservoir of one of the oil fields in southwestern Iran. Based on the obtained results, depth interval 9586 to 9783 ft in the Sarvak Formation, along with two intervals (10661-10815 ft) and (10830-11063 ft) in the Int zone, were identified as potential low-resistivity zones in the reservoir. By analyzing the high-resistivity logs, water saturation percentage was calculated for these zones, and the results from NMR logging confirmed their favorable reservoir potential (e.g., free fluid saturation, effective porosity, viscosity, and permeability).Furthermore, to extend the petrophysical parameters, such as free fluid saturation and porosity, throughout the entire hydrocarbon field, various approaches including single- attribute methods, multi attribute methods, and neural networks were evaluated. The neural network method demonstrated higher accuracy in determining the parameters. Ultimately, the values of porosity and free fluid saturation in the study area were determined with 91% and 95.8% matching accuracy, respectively. The final results were validated using unseen data, and the high precision of the obtained results was confirmed.
- Exploring Geothermal Potential through Multi-Modal Geophysical Data
Integration: Gravity, Magnetic, and Magnetotelluric Prospecting
Abstract: This study presents a comprehensive geophysical investigation of the Sabalan geothermal area in Iran, utilizing Magnetic, Gravity, and Magnetotelluric (MT) data. These data have been inverted to a depth of 5000 meters. Magnetic data inversion. The accurate identification of faults or fractures has been achieved through the inversion of magnetic data. Gravity data inversion produced a density model distinguishing intrusive masses, reservoirs, and cover units. MT data inversion utilized apparent resistivity and phase data for both TM and TE modes. The resulting models were compared with geological cross-sections to assess their accuracy and consistency. The integration of geophysical models yielded a comprehensive geological conceptual model for the Sabalan region. Heat sources, hydrothermal reservoirs, and potential geothermal fluid pathways were identified, demonstrating the effectiveness of geophysical methods in subsurface mapping. Consistency with newer Sabalan models based on drilling and geological data increased confidence in findings.
- Joint Euler deconvolution for depth estimation of potential field magnetic
and gravity data
Abstract: Euler deconvolution system is a well-known approach to estimate the depth of underground sources in potential field geophysics. Over-determined Euler linear equations are usually solved independently and separately for the gravity and magnetic data, and each result is an estimate for the depth of the potential sources. This technique is widely utilized to analyze individually the depth variations of magnetic and gravity sources. However, depth estimation of each of the mentioned potential fields may return specific and exclusive results regarding the complex nature of the subsurface structures, and the gravity and magnetic separate depth estimation solutions may be discordant in many aspects. In cases of low resolution for gravity and magnetic data sets, this study indicates that independently solved Euler depth estimation systems cannot yield reliable and accurate solutions of potential field sources. Combining the gravity and magnetic data and simultaneously solving the Euler equations for gravity and magnetic potential fields, this research presents a novel approach called the joint Euler method with a proper capability to return more accurate and improved depth estimations for boundary and body of potential field sources. The presented method was solved and examined over homogeneous and non-homogeneous synthetic scenarios with reduced resolution, and the depth solutions were also compared with the separate approach. After obtaining the desired results from the synthetic models, the joint Euler technique was applied to the gravity and magnetic data of the Kifl oil trap located in Iraq. The results were quite promising rather than the separate depth estimations, proving the sufficiency and applicability of the proposed potential field method in terms of interpretational aspects.
- Analytical model for studying the effect of weak bedding plane on wellbore
stability
Abstract: Optimum mud weight estimation in wellbore is one of the most important steps to prevent instability. In wellbore stability studies, media (rock) is usually assumed to be isotropic but errors occur when weak bedding planes cause the rocks to be anisotropic. In this study the effect of weak bedding plane in stability of wellbore was studied. Also, the effect of bedding plane parameters on stability of vertical and horizontal wellbore was investigated. Through the use of the geometric relations of bedding plane and wellbore, new equations were presented to calculate the attack angle. Sensitivity analysis on the dip and dip direction of weak bedding plane in the vertical and horizontal wellbore were also performed. On the basis of the porous elasticity theory and Jaeger theories, an analytical model was proposed to analyze the wellbore stability with regard to the dip and dip direction of the weak bedding plane. A code in MATLAB was written based on an analytical model and the effect of the dip and dip direction of the weak bedding plane can be reviewed. By using real data from a wellbore, a comparative analysis was carried out between the new analytical model and the intact rock failure model. Minimum drilling mud weight was calculated in two phases, without weak bedding planes, and with weak bedding planes. Results show that the existence of weak bedding planes causes more instability in the wellbore in some azimuths and deviations. The dip and dip direction of weak bedding planes have a significant impact on the wellbore stability and in the horizontal wellbore according to dip and dip direction, the optimum wellbore trajectory is different. By applying the code, geomechanical engineers can calculate the amount of mud weight based on the dip and dip direction of the weak bedding plane.
- The Complete Model of Wet Air Analysis in Mine Ventilation Design (CMWAA
Method)
Abstract: The ventilation design of mines is done based on fluid dynamics. Air is the main fluid in mining ventilation. This fluid is analyzed in two models incompressibility and compressibility. The air-fluid in the compressibility model is examined in two models of dry and wet air along with thermal analysis. It is argued in this paper that a number of presented parameters in common thermodynamic analysis of mine ventilation should be modified. Accordingly, issues of the Earth's true gravity acceleration, potential energy difference, the specific heat capacity of air at constant pressure and volume, enthalpy difference of air, the average volumetric mass of dry air, and the amount of output moisture are rechecked. Therefore, a new method is presented for correcting thermodynamic equations in mine ventilation design in this paper. The name of this method is the complete model of wet air analysis (CMWAA method). The results of this paper show that the CMWAA method can perform accurate thermodynamic analysis of air-fluid in mine ventilation without specified evaporation rate in mine networks with a minimal iteration of calculations.
- Evaluation of Mining Labor impact on production: Application of
TOPSIS-CRITIC based multiple criteria decision making approach
Abstract: The productivity of the quarry during the wet season depends heavily on how well the personnel adjusts to the mine's environmental conditions and management plans. The improvement of granite production through workers' impact identification and mining advancement decision-making in Ondo State, Nigeria, has been considered in this study. The rate of granite production and the factors influencing workers’ efficiency were assessed using a well-structured survey and descriptive-analytic technique. To improve the production rate, the multiple criteria decision-making (MCDM) technique was used to select the most productive pit depending on a number of key labor impact factors. Health and safety in employment, the energy crisis, Market conditions and level of competition, On-site accidents, Natural disasters, and language barriers were some of the factors identified as mine workers’ external influencer factors affecting mine labor efficiency in granite quarrying. Finally, using the criteria's significance through the inter-criterion (CRITIC) approach, the mine workers’ influence on production was estimated and utilized for the best pit selection. The result of the MCDM revealed that the five pits (Pit 1, Pit 2, Pit 3, Pit 4, and Pit 5) have the following decision performance scores: 0.659, 0.617, 0.5, 0.5, and 0.5, respectively, making Pit 1 the best production pit to be considered during the rainy season. The optimal solution was validated with the 2021 production report. The report shows that Production from Pit 1 has the highest revenue of $16,000 Per annum, the lowest dewatering cost, and the highest production rate as compared to the other four pits.
- Incorporating Topographic Variations on Electrical Resistance Tomography
Abstract: Electrical resistance tomography (ERT) provides images of the electrical properties of subsurface materials leading to the distinction of different Earth’s interior structures. The accuracy of electrical resistance imaging is strongly affected by the topographical variations so that the lack of incorporation of topography information into the inversion process may produce erroneous anomalies in the resistivity section. Owing to the significance of the topography effects on the resistivity measurements, we use a Schwarz-Christoffel transformation approach to incorporate the irregular surface into the 2.5-dimensional forward solution in the framework of the finite difference method. This approach is implemented on synthetic cases to illustrate how the resistivity measurements are dependent on the topographic irregularities. Numerical experiments demonstrate that in the presence of topographic features between current and potential electrodes, the resistivity response does not reflect the realistic resistivity values of the subsurface even in the case of a homogeneous resistivity distribution.
- Investigating the performance of continuous weighting functions in the
integration of exploration data for mineral potential modeling using
artificial neural networks, geometric average and fuzzy gamma operators
Abstract: In mineral exploration programs, reducing uncertainty and increasing the exploration success have always been of challenging issues. To modulate the above-mentioned uncertainty and to increase the exploration success, integration and prospectivity analysis techniques are used for mineral exploration targeting. This paper aims to model mineral potential of porphyry copper deposits in Jiroft region, Kerman province. To achieve this goal and to overcome the aforementioned issues resulting from the operation of complex ore-forming geological processes, continuous weighting methods through logistic functions were used while training points and analyst’s opinion were not contributed in the weighting procedure. Then, to generate exploration targets the weighted layers were combined with three different integration methods namely, artificial neural network, geometric average and fuzzy gamma operators. Comparison of the model obtained from the application of artificial neural network with those models obtained by the geometric average and the fuzzy gamma operators by using prediction rate-area plots, indicated that all the models have good overall performance and acceptable prediction rate. However, the performance of the artificial neural network model is slightly less than that of other two models. Thus, the targets generated using geometric average and fuzzy gamma operators are more reliable for planning further exploration programs.
- Mineral potential mapping of porphyry copper deposit by translating the
mineral system using soil geochemistry data at Kahang, Iran
Abstract: Identification of geochemical anomalies is a critical task in mineral exploration targeting. Decades of research and technology have resulted in new algorithms and techniques being developed for recognizing anomaly detection methods at various scales and sample media. However, algorithms cannot always reveal the true nature of geological processes. The mineral system concept may contribute to a better understanding of the geological processes required to form and preserve ore deposits at all spatial and temporal scales. The mineral systems concept investigates the geochemical processes occurring within mineral subsystems in soil samples from the porphyry prospect area. The Cu/(Al+Ca) index was used in the comparison of Cu, Mo, and (Pb* Zn)/(Cu*Mo) to highlight the region of interest for mineral potential mapping and pioneer borehole drilling based on fluid-rock interaction and secondary processes (e.g., alteration, weathering, and leaching). Exploratory boreholes validate a better-performing Cu/(Al+Ca) index for detecting and refining soil geochemical anomalies.
- Applying deep learning method to develop a fracture modeling for a
fractured carbonate reservoir using geologic, seismic and petrophysical
data
Abstract: Fractures are one of the most important geological features that affect production from most carbonate reservoirs. A large amount of the world’s hydrocarbon resources are located in fractured reservoirs and the identification of fractures is one of the important steps in reservoir development. Due to the high cost of tools that are used in the petroleum industry to identify fractures such as image logs, and their inaccessibility in most of the studied areas, it is often tried to use other available data to identify fractures. Due to the ever-increasing progress of data-driven methods such as neural networks and machine learning, this study has tried to apply a 1D-Convolutional Neural Network (1D-CNN) which is one of the deep learning algorithms on well-logging data and seismic attributes in a carbonate reservoir to identify the existing fractures in the investigating area. The approach used in this research is a binary classification which is applied first in the well location. To validate the method, results are compared with the reports obtained from image logs. Finally, the fracture density map is drawn in the entire reservoir area.
- Gold prospectivity mapping through generation and integration of
geophysical, geochemical, remote sensing and geological evidence layers in
Saqez area, NW Iran
Abstract: This study serves to demonstrate the effective use of geophysical data interpretation in recognizing mineralization-related structural features, through which corresponding structural evidence layers are generated. The evidence layers are, in fact, augmented and enhanced so that when integrated with other geo-exploration evidence layers, more reliable mineral exploration targets are delineated. For this, we first illustrate how aeromagnetic and radiometric data are used to recognize structural features and host rocks related to orogenic gold mineral systems. Then, we demonstrate that the mineralization-related features, recognized through geophysical data interpretation, can be integrated with alterations and the geochemical signature of mineralization to delimit reliable exploration targets.
- Hydrocarbon reservoir potential mapping through Permeability estimation by
a CUDNNLSTM Deep Learning Algorithm
Abstract: Potential mapping of Permeability is a crucial factor in determining the productivity of an oil and gas reservoir. Accurately estimating permeability is essential for optimizing production and reducing operational costs. In this study, we utilized the CUDNNLSTM algorithm to estimate reservoir permeability. The drilling core data was divided into a training pool and a validation pool, with 80% of the data being used for training and 20% for validation. Based on the high variation permeability along the formation, we developed the CUDNNLSTM algorithm for estimating permeability. First, due to the highly dispersed signals from the sonic, density, and neutron logs, which are related to permeability, we adjusted the algorithm to train for 1000 epochs. However, once the validation loss value reached 0.0158, the algorithm automatically stopped the training process in epoch number 500. Within 500 epochs of the algorithm, we achieved an impressive accuracy of 98.42%. Using the algorithm, we estimated the permeabilities of the entire set of wells, and the results were highly satisfactory.
The CUDNNLSTM algorithm due to the large number of neurons and the ability to solve high-order equations on the GPU is a powerful tool for accurately estimating permeability in oil and gas reservoirs. Its ability to handle highly dispersed signals from various logs makes it a valuable asset in optimizing production and reducing operational costs because it is much cheaper than the cost of core extraction and has very high accuracy.
- Geology, mineralization, sulfur isotope and fluid inclusion studies in
Abstract: The study area is located 12 km south of Zahedan city in Sistan-Baluchestan province. This area includes the northern part of Sistan and Baluchestan province, which has a similar geological history as the Chagai belt beyond the Iranian border in Pakistan. The porphyry prospect south of Zahedan is located in the fertile belt of the Sistan suture zone, which includes the Janja, Siastragi, Chahuk and Kuh-e-Lar mineral structures, then leading to the Sindak Pakistan Molybdenum Porphyry Mine. Based on the results of the geological mapping of 1: 5,000 areas, a series of subvolcanic masses with intermediate chemical composition (related to the Zahedan granitoid) have been intruded into the sedimentary host rocks with flysch facies. The zoning of alteration occurrence in the region are concentric and with the center of phyllic and potassic alteration. Pyrite is the most abundant sulfide and chalcopyrite the main copper ore mineral. Mo and Cu mineralization in this area mainly occurred as veinlets in stockwork and dissemination texture. Based on scanning electron microscopy (SEM) studies and using EDS analysis, the presence of molybdenite, copper sulfide minerals were detected along with electrum and gold inclusions in the collected samples. Most of the detected fluid inclusions in study area are of the two, three, and multiphase types, including liquid, vapor, and solid. Due to the trend of salinity changes versus homogenization temperature, the effective fluid densities in the mineralization systems of the region are between 0.8 and more than 1.2 gr / cm3. Based on the salinity percentage (30 to 60 wt% NaCl equivalent) and homogenization temperature (200 to 500°C), the fluid inclusions of the region are in the porphyry range. Fluid δ34S values in the study samples are in the range of 3.4 to 4.6 per thousand. Sulfur isotope analyses indicate a magmatic origin of hydrothermal fluid. In general, based on the geology, mineralization, fluid inclusion, and sulfur stable Isotope studies it can be proposed that probably south Zahedan area is a copper, gold and molybdenum-type porphyry deposit.
- Investigation of the performance of grooved grinding rods as a lifter in a
laboratory rod mill
Abstract: To date, there has been limited research conducted comparing the effects of various grinding media shapes on milling kinetics, load behavior, and mill power draw. However, no research has been conducted on their effects on a lifter. This study aims to fill the gap in knowledge. An investigation into the effect of grinding media shape on the lateral movement of the charge (grinding media and material), by analyzing specific breakage rate parameters in a laboratory dry rod mill, has shown how grinding media can act as a lifter. Two grinding media (simple and grooved rods) were compared. The specific breakage rate parameters were determined using the Austin model. The values related to the μ parameter, whose increase means a decrease in the specific rate of breakage and an increase in the lifting of the grinding media, were equal to 3758.76 and 4144.63 for simple and grooved rods, respectively. Results proved that although the grooved rods have a lower specific breakage rate than simple rods, they can perform well as a lifter. They had the highest cataracting effect of the charge.
- Integrated interpretation of aeromagnetic and aero-radiometric data to
delineate structures and hydrothermal alteration zones associated with
Gold and Base metal Mineralization in Chitipa area, Northern Malawi
Abstract: This study presents an analysis of aeromagnetic and aero-radiometric data from the Chitipa area in northern Malawi to delineate structures, hydrothermal alteration areas, and gold mineral potential zones, as well as to identify prospective regions for further mineral exploration. Airborne geophysical data, specifically aeromagnetic and aero-radiometric data, were utilized. We applied several enhancements and filters to the geophysical data, including reduction to the pole, the first vertical derivatives, analytical signal, tilt angle derivative enhancements, Centre for Exploration Targeting (CET) grid analysis, Euler deconvolution, and radiometric data ratios. The results of the analysis provided detailed information on the subsurface geology and indicate that the area is characterized by faulting and shearing with structures predominantly trending in a northwest direction, and minor trends in the northeast-southwest, east-west, and north-south directions. Zones with hydrothermal alteration were found to coincide with structural associations in the NW part of the study area, indicating that the structures served as channel ways for migrating hydrothermal fluids that reacted with the rock formation, resulting in alteration. The northwest area is a promising mineralization zone, and further exploration should focus on this area.
- The effect of high voltage electric pulse on the coarse particle flotation
of sulfur-bearing iron ore samples
Abstract: In this research, the effect of the high-voltage electric pulse (HVEP) crushing on the flotation of high-sulfur iron ore concentrate in the coarse particle fraction was studied compared to mechanical (conventional) crushing. A jaw crusher, a cone crusher, and a high-voltage electric pulse crushing device with a voltage level of 50 kV were used to investigate the effect of mechanical and electrical crushing. The results showed that a coarser particle product was produced with less slime in primary crushing with electric pulses compared to primary mechanical crushing. It was due to the crushing mechanism, which is based on separating minerals with a different dielectric constant from their connection boundaries and also encompasses a selective separation process. The effect of the mentioned method on coarser fractions led to the creation of cracks/microcracks in particle structures that made grinding easier and faster. In investigating the effect of particle size on pyrite flotation and desulfurization at -300 µm (d80=300µm), the sulfur grade of flotation iron concentrate samples using primary crushing was 0.86% and 0.36%, respectively, and at -150 µm (d80=150µm) fraction, the sulfur grade was found to be 0.33% and 0.19% respectively for mechanical and electrical methods. Also, the sulfur removal (recovery) of the sample with primary electrical crushing was 73.7% at a -300 µm fraction, almost equal to 73.2% at the size range of -150 µm with applying the mechanical method. These results indicated the flotation possibility of coarser particles using electrical crushing and desulfurization similarity to the samples with primary mechanical crushing in finer fractions.
- A multi-disciplinary and exploratory geospatial data set integration for
porphyry copper prospectivity mapping in Kerman belt, Iran
Abstract: The Mineral Prospectivity Map (MPM) is a powerful tool for identifying target areas for the exploration of undiscovered mineral deposits. In this study, a knowledge-driven Index overlay technique was utilized to create the MPM on a regional scale. The complex distribution patterns of geological features associated with mineral deposits were mapped and correlations between these features and mineral deposits were revealed by integrating geological, geophysical, hydrothermal alteration, and fault density data layers. It was found that 23% of the study area was highly prospective, with 77% of the known porphyry copper occurrences located within this area. The normalized density was equal to 3.35, indicating a significant relationship between the known porphyry copper occurrences and their occupied area. The MPM also identified potential tracts outside the known mineralized areas that can be used for exploration and quantitative assessment of undiscovered resources. It is suggested that the MPM is a valuable tool for mineral exploration and could have significant implications for the mining industry.
- Structural interpretation of the Mangochi-Makanjira area (Southern Malawi)
from an aeromagnetic analysis: Implications for gold exploration
Abstract: Malawi’s geology has not been mapped in detail and there is no detailed geological and structural assessment in relation to gold mineralization. Mangochi-Makanjira area in southern Malawi is endowed with abundant gold mineral resources but there is a scarcity of precise knowledge on the structures that control primary mineralization. This study used aeromagnetic data to provide a structural framework of the Makanjira area and delineated potential areas for further gold exploration. Many analytic approaches were applied to the aeromagnetic data, including reduction to the pole, Euler deconvolution, Tilt, and Vertical Derivatives filtering. Euler deconvolution was used to determine the depth of magnetic sources. Geophysical data interpretations identify the dominant linear trends present in the area to be faults, dykes and deep level basement shear zones as structures responsible for fluid flow and gold mineralization in the area. Gold in this area is structurally controlled by N-S structures that were derived during the Pan African orogeny and it is during in this event that the area got mineralized. These fractures and faults served as channel ways for hydrothermal solutions, resulting in the emplacement of gold mineralization within the fractures. Mineralization occurs from the surface and goes deep and ranges in depth from 0.5 km to 2.4 km. Exploration for gold should focus on these structures.
- Using magnetic data for estimating the location of lateral boundaries and
the depth of the shallow salt dome of Aji-Chai, East Azerbaijan Province,
Iran
Abstract: Magnetic data play a significant role in the interpretation of various geologic structures using depth estimation methods and edge detection filters. In this study, we applied methods based on directional derivatives such as tilt-depth (TD), signum transform (ST), source distance (SD) and classical Euler deconvolution (ED) to estimate the depth of the magnetic sources. Moreover, to enhance the edges of magnetic field anomalies, we utilize the total horizontal derivative (THD), analytical signal (AS), tilt angle (TA), theta map (TM), hyperbolic tilt angle (HTA), the tilt angle of horizontal derivative (TAHG), and logistic function of total horizontal gradient (LTHD). These algorithms are tested on a synthetic magnetic model with noise and free noise to understand their performance. Since the edge detection filters are sensitive to noise, we carry out an upward continuation (UC) filter before the reduction of data to magnetic the pole to reduce the noise effect. After comparing the efficiency of the approaches in estimating the depth and horizontal lateral boundaries, these methods were applied to the data surveyed from the Aji-Chai salt dome in East Azerbaijan Province, Iran. The results obtained by the depth determination methods were compared with the drilling report of Iran’s geological survey and three-dimensional classical Euler deconvolution method.
- Edge detection of geological structures of based on a logistic function: a
case study for gravity data of the Western Carpathians
Abstract: Magnetic and gravity anomalies have spatially overlapping fingerprints from many buried sources that differ in shape, depth, density contrast, magnetization intensity, and direction. Geophysicists have developed a suite of image enhancement filter algorithms that accurately represent the geometry and detail of subsurface features. Edge enhancement filters are high-pass filters that emphasize potential field anomalies, horizontal lateral edges, and the horizontal location of buried sources, i.e., specific combinations of directional derivatives of gravity and magnetic fields. Lateral edge enhancement filters (e.g., THG, AS, TA, TM, LTHG, IL, and ILTHG) were investigated using Gaussian noise on synthetic magnetic and gravity field data. The results show that LTHG and IL perform better than the other procedures. The ILTHG filter defined with the logistic function does not have the required accuracy and capability to determine the lateral boundaries. In addition, the filters were examined using real gravity field data from the Western Carpathians area in Slovakia. The primary and secondary faults in the western and southern Tribeč Mountains and the secondary faults and geological formations in the Pohronský Inovec Mountains are recognizable in the LTHG and IL images. The results of the LTHG and IL maps will allow us to improve the qualitative interpretation of gravity anomalies in studying the structural and tectonic geology of the Slovak Tribeč and Pohronský Inovec Mountains.
- Recognition coefficient of spatial geological features, an approach to
facilitate criteria weighting for mineral exploration targeting
Abstract: The different methods for the delineation of favorable areas for mineral exploration utilize exploration criteria in regard to targeted mineral deposits. The criteria are elicited according to conceptual model parameters of the targeted mineral deposits. The selection of indicator criteria, the evaluation of their comparative importance, and their integration are critical in mineral prospectivity modeling. In data-driven methods, indicator features are weighted using functions whereby the importance of certain indicator criteria may be ignored. In this paper, a data-driven method is described for recognizing and converting exploration criteria into quantitative coefficients representing favorability for the presence of the targeted mineral deposits. In this approach, all of the indicator features of the targeted mineral deposits are recognized and incorporated into the modeling procedure. The method is demonstrated for outlining favorable areas for Mississippi valley-type fluorite deposits in an area, north of Iran. The method is developed by studying and modeling the geological characteristics of known mineral occurrences. The degree of prediction ability of each exploration criterion is quantified as a recognition coefficient, which can be used as a weight attributed to the criterion in mineral exploration targeting to outline favorable areas.
- A Hybrid Fuzzy Ordered Weighted Averaging Method in Mineral Prospectivity
Mapping: a case for Porphyry Cu Exploration in Chahargonbad District, Iran
Abstract: This research case study presents a fuzzy ordered weighted averaging (FOWA) method for mineral prospectivity/potential mapping (MPM) at Chahargonbad district in SE Iran, a system whereby new areas of high prospectivity for porphyry Cu mineralization are identified. The ultimate goal of this research is to find the complex and hidden relationships between the evidence layers and known ore occurrences using a comprehensive consideration of a multi-disciplinary geospatial data set. Hence, thirteen evidences are accurately derived from available databases, including geological, geochemical, geophysical, and remote sensing, and integrated through a FOWA multi-criteria decision-making approach to delineate favorable Cu-bearing zones. FOWA methodology uses a wide range of decision strategies to synthesize input geospatial evidences utilizing multiple values for an alpha parameter as the cornerstone of the algorithm that controls the experts' attitude toward the MPM risk. It is reflected through the generation of seven mineral potential maps to search the most suitable one(s). Considering a prediction-area plot for data-driven weight assignment of each evidence map, the hybrid FOWA outputs are searched for the most appropriate map in targeting notable Cu occurrences. The desired synthesized evidence map could indicate an ore prediction rate of 77%, where known Cu deposits were distributed at favorable zones occupying 23% of the whole district area.
- A potential field geophysical study to image a Potash resource through
Depth from Extreme Points, Ghareh-Aghaj deposit in NW of Iran
Abstract: Based on magnetic susceptibility and density contrast models, the final purpose of analyzing potential field data is to estimate the parameters of the sought source, such as depth, structural index, horizontal location, and physical characteristics. Meanwhile, when conducting geophysical explorations, it is critical to ascertain the exact depth of the underground source as accurately as possible. In this study, the potential field is interpreted using the depth from extreme points “DEXP” automatic transformation technique, founded on the accurate processing of the local wavenumber at various scales and the extreme points of the DEXP field to extract the depth, horizontal position and structural index of the source. This highly stable method demonstrates low sensitivity to noise-contaminated data since it employs an upward continuation filter and a potential field derivative operator. In addition, the findings are more dependable than those of alternative techniques. Furthermore, the procedure is entirely automatic and does not require any basic information from the data collection area. In other words, DEXP can be considered a fast imaging method. Since multiscale methods are less reliant on the magnetic induction field, nowadays, they are utilized more frequently in magnetic field computations. At the beginning of this research, synthetic scenarios are simulated, and then the depth extension of the postulated models was demonstrated by implementing the DEXP technique to the synthetic gravity and magnetic data. Subsequently, this method has been implemented on data from the Ghareh-Aghaj potash exploratory area in Zanjan Province, North of Iran. By summarizing this method's results, it can be seen that the potash mass exhibits a minimal transverse expansion and has extended more in the depth dimension. Compared to the findings obtained via exploratory boreholes, these findings demonstrate a level of agreement that can be considered satisfactory.
- Analyzing the effects of natural ventilation caused by excavating the
waste pass on the ventilation network of Anguran mine
Abstract: One of the operating costs of exploiting underground mines is related to ventilation operations. The development of the underground network during the mine life and new excavations will cause a redesign of the ventilation plan over and over again. Excavating the waste pass in the Anguran underground lead and zinc mine and developing new access for the transfer of cement filling requirements from the surface will make it necessary to review the ventilation network plan. The present research aims to analyze the efficiency of the mine ventilation network through simulation with considering the effects of waste pass based on the consequences of natural ventilation. For this purpose, based on the estimation of the needs of the underground development plan, the required airflow intensity of this mine was 57.5 m3/sec and the air pressure drop was estimated to be 116.79 millimeters of the water column. The underground mine network was imported into the software by using Ventsim software, and the simulation and specifications of each branch have also been entered. Then, different positions of the main fan were examined according to the location of mine opening and airways the advantage of mine natural ventilation in different seasons, and finally, the most suitable design for ventilation was presented. Modeling natural ventilation was investigated in two parts before waste/ore pass excavation and after excavation in Ventsim software at temperature, pressure, and different humidity. According to the simulation, it was found that the minimum natural ventilation flow to the mining network is 14 m3/sec in winter, its use saves 16.02 Kwh of energy.
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