Subjects -> MINES AND MINING INDUSTRY (Total: 82 journals)
Showing 1 - 42 of 42 Journals sorted alphabetically
American Mineralogist     Hybrid Journal   (Followers: 16)
Applied Earth Science : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Archives of Mining Sciences     Open Access   (Followers: 3)
AusiMM Bulletin     Full-text available via subscription   (Followers: 1)
BHM Berg- und Hüttenmännische Monatshefte     Hybrid Journal   (Followers: 2)
Canadian Mineralogist     Full-text available via subscription   (Followers: 7)
CIM Journal     Hybrid Journal  
Clay Minerals     Hybrid Journal   (Followers: 9)
Clays and Clay Minerals     Hybrid Journal   (Followers: 5)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 14)
Environmental Geochemistry and Health     Hybrid Journal   (Followers: 3)
European Journal of Mineralogy     Hybrid Journal   (Followers: 14)
Exploration and Mining Geology     Full-text available via subscription   (Followers: 3)
Extractive Industries and Society     Hybrid Journal   (Followers: 2)
Gems & Gemology     Full-text available via subscription   (Followers: 2)
Geology of Ore Deposits     Hybrid Journal   (Followers: 5)
Geomaterials     Open Access   (Followers: 3)
Geotechnical and Geological Engineering     Hybrid Journal   (Followers: 9)
Ghana Mining Journal     Full-text available via subscription   (Followers: 3)
Gold Bulletin     Hybrid Journal   (Followers: 2)
Inside Mining     Full-text available via subscription  
International Journal of Coal Geology     Hybrid Journal   (Followers: 4)
International Journal of Coal Preparation and Utilization     Hybrid Journal   (Followers: 2)
International Journal of Coal Science & Technology     Open Access   (Followers: 1)
International Journal of Hospitality & Tourism Administration     Hybrid Journal   (Followers: 15)
International Journal of Mineral Processing     Hybrid Journal   (Followers: 8)
International Journal of Minerals, Metallurgy, and Materials     Hybrid Journal   (Followers: 12)
International Journal of Mining and Geo-Engineering     Open Access   (Followers: 4)
International Journal of Mining and Mineral Engineering     Hybrid Journal   (Followers: 8)
International Journal of Mining Engineering and Mineral Processing     Open Access   (Followers: 6)
International Journal of Mining Science and Technology     Open Access   (Followers: 4)
International Journal of Mining, Reclamation and Environment     Hybrid Journal   (Followers: 6)
International Journal of Rock Mechanics and Mining Sciences     Hybrid Journal   (Followers: 9)
Journal of Analytical and Numerical Methods in Mining Engineering     Open Access  
Journal of Applied Geophysics     Hybrid Journal   (Followers: 18)
Journal of Central South University     Hybrid Journal   (Followers: 1)
Journal of China Coal Society     Open Access  
Journal of China University of Mining and Technology     Full-text available via subscription   (Followers: 1)
Journal of Convention & Event Tourism     Hybrid Journal   (Followers: 6)
Journal of Geology and Mining Research     Open Access   (Followers: 10)
Journal of Human Resources in Hospitality & Tourism     Hybrid Journal   (Followers: 9)
Journal of Materials Research and Technology     Open Access   (Followers: 2)
Journal of Metamorphic Geology     Hybrid Journal   (Followers: 17)
Journal of Mining Institute     Open Access  
Journal of Mining Science     Hybrid Journal   (Followers: 5)
Journal of Quality Assurance in Hospitality & Tourism     Hybrid Journal   (Followers: 6)
Journal of Sustainable Mining     Open Access   (Followers: 3)
Journal of the Southern African Institute of Mining and Metallurgy     Open Access   (Followers: 6)
Lithology and Mineral Resources     Hybrid Journal   (Followers: 4)
Lithos     Hybrid Journal   (Followers: 11)
Mine Water and the Environment     Hybrid Journal   (Followers: 5)
Mineral Economics     Hybrid Journal   (Followers: 2)
Mineral Processing and Extractive Metallurgy : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 14)
Mineral Processing and Extractive Metallurgy Review     Hybrid Journal   (Followers: 5)
Mineralium Deposita     Hybrid Journal   (Followers: 4)
Mineralogia     Open Access   (Followers: 2)
Mineralogical Magazine     Hybrid Journal   (Followers: 1)
Mineralogy and Petrology     Hybrid Journal   (Followers: 5)
Minerals     Open Access   (Followers: 2)
Minerals & Energy - Raw Materials Report     Hybrid Journal   (Followers: 1)
Minerals Engineering     Hybrid Journal   (Followers: 14)
Mining Engineering     Full-text available via subscription   (Followers: 7)
Mining Journal     Full-text available via subscription   (Followers: 4)
Mining Report     Hybrid Journal   (Followers: 3)
Mining Technology : Transactions of the Institutions of Mining and Metallurgy     Hybrid Journal   (Followers: 4)
Mining, Metallurgy & Exploration     Hybrid Journal  
Natural Resources & Engineering     Hybrid Journal  
Natural Resources Research     Hybrid Journal   (Followers: 5)
Neues Jahrbuch für Mineralogie - Abhandlungen     Full-text available via subscription   (Followers: 1)
Physics and Chemistry of Minerals     Hybrid Journal   (Followers: 4)
Podzemni Radovi     Open Access  
Rangeland Journal     Hybrid Journal   (Followers: 4)
Réalités industrielles     Full-text available via subscription  
Rem : Revista Escola de Minas     Open Access  
Resources Policy     Hybrid Journal   (Followers: 4)
Reviews in Mineralogy and Geochemistry     Hybrid Journal   (Followers: 5)
Revista del Instituto de Investigación de la Facultad de Ingeniería Geológica, Minera, Metalurgica y Geográfica     Open Access  
Rock Mechanics and Rock Engineering     Hybrid Journal   (Followers: 9)
Rocks & Minerals     Hybrid Journal   (Followers: 5)
Rudarsko-geološko-naftni Zbornik     Open Access  
Transactions of Nonferrous Metals Society of China     Hybrid Journal   (Followers: 9)
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Journal Cover
Journal of Analytical and Numerical Methods in Mining Engineering
Number of Followers: 0  

  This is an Open Access Journal Open Access journal
ISSN (Print) 2251-6565 - ISSN (Online) 2676-6795
Published by Yazd University Homepage  [1 journal]
  • Key group analysis based on DDA method for rock slope stability analysis

    • Abstract: Inhomogeneity and discontinuities play a key role in resistance and behavior of rock masses. Today engineers have a wide range of methods to analyze the stability of rock slopes. Due to its simplicity and speed of evaluation, static analysis methods continue to play a special role in the stability assessment of jointed rock slopes. One of the most well-known static methods used in the stability analysis of rock slopes is the Key Block method (KBM), which is based on the key block finding and analyzing. In this method, if none of the key blocks are unstable, it implies that rock mass is stable. Occasionally, the combination of a number of stable blocks has led to formation a group of blocks that sometimes leads to instability. Therefore, the stability analysis of the jointed rock masses leads to study of groups of blocks that are potentially dangerous for the stability of a rock slope. The Key Group method (KGM), with its progressive approach, finds these critical groups and focuses the stability calculations on these groups. In order to increase the efficiency, accuracy and speed of this method and to develop it in three dimensions, it is decided to combine it with one of the numerical methods. The standard Discontinuous Deformation Analysis method (DDA) is an implicit method based on the finite element method. This is a sophisticated numerical method for modeling the quasi-static and dynamic behavior of rock block systems in discontinuous rock masses. The goal of this paper is to use of the potency of the numerical method of DDA to analyze the candidate key group. For this purpose, the DDA computer program was developed with Mathematica programming language and combined with the KGM software. The resulting package, after selecting the key group by the KGM method, proceeds to analyze it with the DDA method. Two examples solved illustrating the reasonable results and the efficiency of this developed method compared to that of the original KGM and SKGM. The results validated the proper accuracy and good performance of the procedure developed in this research.
      PubDate: Sun, 17 Jan 2021 20:30:00 +010
       
  • Investigation of bubble velocity profile in the column flotation cell by
           computational fluid ...

    • Abstract: Hydrodynamic components play an important role in performance of column flotation. Computational fluid dynamics (CFD) as a numerical method can be helpful in analyzing and predicting flow components. In this paper, the single bubble rising velocity profile in the flotation column is studied in two-phase with CFD. Simulations have been performed in Fluent software using a two-phase VOF model. A computational column with a square cross section of 10 cm and a height of 100 cm has been considered. The air is entered via a single bubble from the bottom of the column by an internal sparger. To validate the simulation results, a series of experiments have been performed, while imaging has been used to record hydrodynamics such as inlet air flow, bubble diameter and bubble rise velocity. The experimental results are consistent with previous observations studied by others. Also, the results of the simulations are qualitatively and quantitatively consistent with the experimental results. The results show that CFD simulation can well predict the rise of the bubble and its related parameters in the flotation column, including the bubble rise rate with a difference of less than 5% compared to the experimental values.SummaryIn this paper, the single bubble rising velocity profile in the flotation column is studied in two-phase with CFD.IntroductionThis article consisted of two parts: the experimental tests and the CFD simulations. The authors tried to present a set of setting to simulate the bubble rising velocity as good as possible by their facilities.Methodology and ApproachesSimulations have been performed in Fluent software using a two-phase VOF model. A computational column with a square cross section of 10 cm and a height of 100 cm has been considered. The air is entered by a single bubble from the bottom of the column by an internal sparger. To validate the simulation results, a series of experiments have been performed, while imaging was used to record hydrodynamic components. Results and ConclusionsThe results show that CFD simulation can well predict the rise of the bubble and its related parameters in the flotation column, including the bubble rise rate with a difference of less than 5% compared to the experimental values.
      PubDate: Fri, 01 Jan 2021 20:30:00 +010
       
  • Combination of Remote Sensing and Ground Penetrating Radar methods to
           estimate suitable areas ...

    • Abstract: The subsurface dam is considered a way to store and utilize subsurface flow in dry and warm areas. In this study, the appropriate locations for constructing a subsurface dam in an Abouzeidabad plain were pinpointed using remote sensing and geophysical methods. To this end, topography, slope, lithology, land use, stream density, fault density, and qanat density information layers were provided. In providing these layers, Digital Elevation Model (DEM) and Landsat 8 satellite images were used. Due to the importance of alluvial formations in the reservoir volume of the subsurface dam, the lithology layer in the form of a geology map subject was made to separate the formations suitable for the dam storage. Analytical Hierarchy Process (AHP) method was used to compare and evaluate the layers and substrates. A final map of location priorities for the construction of a subsurface dam was then developed using the results from the AHP method. After identifying three locations of high priority (4 to 5), the geophysical data were collected from these locations using Ground Penetrating Radar (GPR) method to determine the bedrock position and alluvium thickness in each cross-section. Using the obtained data and hydrological information of the area, discharge capacity was calculated for each of the identified locations. At the most appropriate location, a subsurface dam with 311 meters length and 17 meters depth was proposed to reach the discharge capacity of over 4.35 million cubic meters, which is considerable for supplying the water demands of downstream regions including Badroud and Abouzeidabad.
      PubDate: Sun, 20 Dec 2020 20:30:00 +010
       
  • Estimation of REV size and Determination of geo-mechanical properties of
           the rock mass in ...

    • Abstract: Representative Elementary Volume (REV) size study was carried out for data of Sechahoon Anomaly XII mine by using a discrete fracture network and distinct element method to characterize mechanical and behavioral properties of a highly jointed rock mass. By studying on scale dependency of mechanical properties of the rock mass, REV size was determined. On the other hand, for continuum modeling of rock mass because of the inherent uncertainty in geometrical and mechanical characteristics, 39 sample models were generated stochastically based on geometry variation of joints. Uniaxial and triaxial compressive tests were performed and finally, distributions of UCS, deformability modulus, cohesion, and friction angle of rock mass were obtained. These can be used for reliability and probability investigation of the rock mass.
      PubDate: Sun, 20 Dec 2020 20:30:00 +010
       
  • On the Effect of Grain Size on Rock Behavior under Cyclic Loading by
           Distinct Element Method

    • Abstract: It is well-known that the mechanical behavior of rocks under cyclic loading is much different from static loading conditions. In most constructions, the load applied to structures is within dynamic ranges. That’s why a great deal of attention has been paid to this field to identify the dynamic behavior of rocks in more detail. Nevertheless, the nature of dynamic failure in rocks has not yet been identified, particularly when it comes to cyclic loading The purpose of this study was to investigate the influence of grain size on the mechanical behavior of rocks under cyclic loading using numerical modeling by UDEC. A total of three grain-categories with a diameter of 1, 2, and 4 mm were modeled in the software. All models were of Brazilian type with 54 mm diameter. Behavioral parameters required for modeling were determined through laboratory studies and the software was adjusted accordingly. The stresses applied to the samples were in two forms of quasi-static and cyclic loading. The result of static loading is that the smaller the grain size, the model will have a higher elastic modulus. In other words, the elastic modulus of the grain size is inversely related to the grain dimensions. Analysis of data obtained from cyclic loading showed that the amount of strain in samples with smaller grain sizes was lower than the corresponding strain in samples with larger grain sizes during the same loading periods. In other words, the resistance of samples with smaller grain sizes to deformation under cyclic load was higher compared to those with larger grain sizes. Comparison of the stress vectors for these samples showed that with a decrease in grain size, stress distribution in the sample became more uniform and inclusive, and the stress concentration declined. Another important result was that the smaller the grain size, the more the axial stress applied to the sample inclined towards one. This indicated that with a decrease in grain dimensions, the sample behavior approached a plastic behavior.
      PubDate: Sun, 20 Dec 2020 20:30:00 +010
       
  • A Critique on Power Spectrum – Area Fractal Method for Geochemical
           Anomaly Mapping

    • Abstract: Power spectrum – area fractal (S-A fractal) method has been frequently applied for geochemical anomaly mapping. Some researchers have performed this method for separation of geochemical anomaly, background and noise and have delineated their distribution maps. In this research, surface geochemical data of Zafarghand Cu-Mo mineralization area have been utilized and some defects of S-A fractal method have been discussed. The surface geochemical data were transformed to the frequency domain using Fourier transformation and the S-A fractal method was performed on obtained Cu power spectrum. 4 geochemical classes were distinguished on the basis of fractal diagram then these classes were separated using various filters and their signals were analyzed separately by principal component analysis (PCA) and the situation of mineralization was interpreted. PCA shows the low frequency geochemical signals have strongly been affected by the Cu and Mo mineralization process. In the end, the Cu geochemical anomaly map based on this low frequency class was delineated using inverse Fourier transformation. The deep borehole that was drilled in the center of this obtained anomaly shows there is a mineralization zone at the depth. The disadvantages of S-A fractal method have been discussed using these obtained results.
      PubDate: Sun, 20 Dec 2020 20:30:00 +010
       
  • Designing an entrepreneurial policy model in the field of mines in Sistan
           and Baluchestan province

    • Abstract: Recognizing the comparative advantages of different regions and creating infrastructure to properly direct capital and resources to generate wealth and added value is one of the main tasks of policymakers in each country, doubling the importance of this sector. Therefore, designing a model for the development of mining entrepreneurship can directly and indirectly play an effective role in economic development, especially in deprived areas. Therefore, this article tries to address this issue with a hybrid approach.Research Method The present paper has a combined exploratory approach that uses data-based theory to analyze interviews and structural path analysis technique to test the explanatory model relationships. According to the data analysis, a process and multidimensional model has been presented for the first time at the level of mining businesses to explain entrepreneurial policy in the field of mines in Sistan and Baluchestan province.The research findings indicate that the proposed strategies for entrepreneurship development in the province's mines are in order of priority: Transformation of research and development in the mining sector (0.78), privatization of the mining sector (0.17), and integration of knowledge and mining activities (0.16). Also, the results of entrepreneurship in the field of mines are in order of priority: Competitiveness in attracting investors (0.65), improving the productivity of mining activities (0.34), branding in the field of mines (0.08) and positioning for mining (0.07) .
      PubDate: Tue, 15 Dec 2020 20:30:00 +010
       
  • 3D Cross-Correlation Modelling of Shavvaz mine’s Magnetometry data,
           Yazd, Iran

    • Abstract: This article introduces the 3D Cross Correlation for modelling of total magnetic intensity and its vertical gradient which is the fast way to model data, detect anomalies and estimate their depths and locations. In this approach first, we divide the subsurface space into a 3D regular grid, after computing the correlation value for each node of the grid, these values are plotted. It is noted that the results fall in the range [-1 +1] that represents the mass excess or mass deficit of magnetization (or susceptibility) relative to the magnetization (or susceptibility) of the host volume. This approach is applied to 2 synthetic models. The results show acceptable accuracy of this method in depth estimation and expansion of buried masses. After this method is verified and validated, it will be applied to the Shavvaz mine’s total magnetic intensity (TMI) data of Yazd and its vertical gradient, and the results will be discussed.
      PubDate: Mon, 26 Oct 2020 20:30:00 +010
       
  • Seismic data inversion using an optimal least square reverse time
           migration

    • Abstract: Due to the drawbacks of beam-based seismic imaging methods, the use of wavefield-based imaging methods such as reverse-time migration (RTM) as a suitable alternative has been greatly welcomed in recent years. However, as the RTM is implemented using wave field reconstruction and cross-correlation imaging condition, it produces artifacts which is the major challenge of RTM. Therefore, in this paper, the inversion of seismic data is used by integration of RTM modeling operators and least squares migration to produce subsurface image. The least squares reverse time migration (LSRTM) method is implemented using the steepest decent and adaptive gradient methods in an iterative procedure including forward migration and inverse migration to solve the least squares problem. The LSRTM algorithm tries to fit a better depth model to the observed data based on the least-squares. Then the migrated images results of LSRTM procedure are presented using the steepest decent and adaptive gradient algorithms in different iterations which compared with each other and with conventional RTM. Finally, the misfit error and also the wavenumber spectra versus normalized amplitude has been compared for the disputed methods.
      PubDate: Sun, 25 Oct 2020 20:30:00 +010
       
  • Statistical and intelligent modeling of stability state for different
           surfaces of underground ...

    • Abstract: Stability of open stopes in hard rock underground mining is typically evaluated using the stability graph method. Due to the empirical nature of this method, lack of an unique graph for various conditions and considering the same conditions for the various surfaces of the stope, the risk of wrongly interpreting the results is high. In this paper new models to evaluate stability state of open stopes based upon input parameters of stability graph method were developed separately for roof and walls using logistic regression and support vector machine (SVM). For this purpose, a database was established containing conditions of roof and walls from open stope mines in Canada and Ghana. The results indicated that the accuracy of stability graph method, LG model and SVM model in prediction of roof stability were 29%, 86% and 95%, respectively. In addition, the accuracy of wall stability condition prediction using stability graph method, LG model and SVM model were 71%, 81% and 90%, respectively. These results confirm that the performance of developed model is better than conventional stability graph method. Besides, it was concluded that SVM models possesses a higher performance in stability evaluation when compared to the LG models. Findings of this paper show that separation of different open stopes surfaces as well as incorporating statistical and intelligent methods in stability evaluation increase the reliability of predictions in comparison with conventional stability graph method.
      PubDate: Sun, 25 Oct 2020 20:30:00 +010
       
  • Numerical investigation of the interaction of adjacent tunnels - Influence
           of excavation ...

    • Abstract: Today, due to the development of cities and the lack of space on the ground, as well as the increase in traffic problems, the need to build underground spaces to develop urban transportation systems has increased. This study also examines the effect of the sequence of excavation of adjacent tunnels. The case study used in this study is the access tunnels of Iran Mall collection. For numerical modeling, the Midas GTS finite element software is used in 3D mode, and the effect of the sequence of tunnel excavation on the surface settlement and the internal forces of the structures of these tunnels have been investigated. The results showed that successive excavation of adjacent tunnels resulted in lower settlement values than the simultaneous excavation of tunnels and had a significant effect on the temporary support of the tunnels in the values of forces and bending moment. Finally, in order to validate the results of the surface settlement obtained from the numerical model, the monitoring data of the surface settlement of Iran Mall project were used, it was determined that the numerical results are close to the monitoring data.
      PubDate: Fri, 23 Oct 2020 20:30:00 +010
       
  • Application of Discrete Elemental Numerical Modeling for Optimization of
           Sealing System of ...

    • Abstract: A common method to control water seepage from under the dam foundation is to construct a sealing curtain. Seal curtain construction is one of the most common methods to control seepage under the dams. A number of wells have been drill in order to make the sealing curtain and injections are performed in these wells. In the injection operation, the joints in the rock mass are filled using appropriate slurry. Since rock material permeability is very low and negligible, the depth of slurry seepage depends on several parameters such as slurry properties, grouting pressure, and discontinuities characteristics. To determine the optimal pattern of grouting holes, the use of numerical methods can save costs and reduce the time operation. In this paper, considering the rock mass properties in the Sardasht dam construction area, using UDEC discrete element software, the optimal design of the dam sealing system is investigated. Based on the results of numerical modeling, the optimum depth of 40m curtain, the distance between the grouting holes, and the supports are suggested as 3m and 5m, respectively. Also, the optimum deviation angle of the holes is estimated to be 17 degrees. Comparing the results of numerical modeling with the measured values indicates the high capability of the numerical method in determining grouting pressure and leakage analysis of Sardasht dam.
      PubDate: Wed, 21 Oct 2020 20:30:00 +010
       
  • Investigation of the effect of different parameters on the penetration
           rate of earth pressure ...

    • Abstract: One of the most widely used methods for excavation of metro tunnels is mechanized excavation using earth pressure balance (EPB) boring machine. In mechanized excavation, predicting the penetration rate of the boring machine has a great effect on reducing costs. Geological and geotechnical factors, machine specifications and operational parameters can be influential on the penetration rate of the machine. Important geotechnical factors include cohesion, friction angle and soil shear modulus. Among the important machine parameters, the thrust force of the jacks, the torque and the rotational speed of the cutterhead can be mentioned. In this study, after analyzing the main component, eliminating the outlier data and normalizing the data, by considering the geotechnical factors and various parameters of the mechanized boring machine, the penetration rate of the EPB machine in the Tabriz metro line 2 tunnel has been predicted. For this purpose, linear regression methods, fuzzy logic using Mamdani and Sugeno algorithms, neuro-fuzzy method and metaheuristic algorithms were used. To validate each model, statistical indices of the coefficient of determination (R^2), root mean squares error (RMSE) and performance indicator (VAF) were used. The results of the studies showed that the neuro-fuzzy method has a better prediction of the penetration rate in comparison to other methods. Also, the results of sensitivity analysis revealed that the cutterhead torque had the greatest effect on the penetration rate of the EPB machine.
      PubDate: Mon, 21 Sep 2020 20:30:00 +010
       
  • Comparison ore and waste classification based on the result of Log-kriging
           and localized ...

    • Abstract: In the cases of the distance between data is large compared with the dimensions of the block, using the estimation techniques based on linear regression for modeling small blocks are inappropriate. It is proposed to overcome this problem; use a new method called localized uniform conditioning (LUC) which is result of a series of corrections on a uniform method (UC). In this research, the application of this method for SMU classification into waste and ore based on 0.2% cutoff grade has been compared with the conventional estimation method in the Miduk copper mine. Based on the blast holes, for the two extraction panels, 2450 and 2465, their results showed that the total blocks were separated to 4% waste and 96% of the ore; therefore, the ore percentage changes were considered for the conclusion. For the method of Log-kriging, in these two panels, 49% of the separation of the ore is matched with the ore control output, while in the 51% of the cases the ore classified as waste. Also, according to the outputs of the localized uniform conditioning method, in these two benches, 98% of the classification of the ore was matched to the ore control output, and 2% of the separation of the ore was classified as waste. Therefore, even assuming the same level of cost due to under estimation and over estimation, the localized uniform conditioning method is more desirable.
      PubDate: Sat, 05 Sep 2020 19:30:00 +010
       
  • Determination of optimized block sizes using geostatistical and simulation
           methods in reserve ...

    • Abstract: In this study the optimized size for block modeling and the role of block size in reserve estimation were investigated. For this purpose, the deposits with different genesis were considered as case studies in order to investigate the effect of different variability in block size optimization. For this plan, the data of Surk iron ore and Esfordi phosphate deposits were used. The database was built using borehole data and the composite samples were prepared with length of 2 m. The data was converted to normal distribution using normal score transformation. Variography was used for investigate ore continuity and variability and the suitable variograms and anisotropy ellipsoids were obtained. Totally 256 block models were made for Surk and Esfordi deposits and the kriging efficiency was calculated in different block size. Due to proposed large block sizes in comparison to operational models and their incoherency to real anisotropy ratios, the method was ignored. In the next approach, the Gaussian Conditional Simulation method was used for different block size investigation. In each simulation, 20 realizations were produced and the variance between realizations was calculated. The less variance is the more similarity of realizations, which is the criterion for choosing the optimal block sizes. By this method the block dimension of 7.5*7.5*7.5 and 10*7.5*10 were calculated for Surk and for Esfordi deposits, respectively. The calculated block sizes were in good agreement with operational conditions and the anisotropy ratios. Therefore the obtained block sizes were used in reserve estimation of the deposits. The estimated reserves were 9.84 Mt for Surk in cut off grade 20% of iron and 11.93 Mt for Esfordi deposit on the basis of 5% cut off grade of phosphorus.
      PubDate: Wed, 20 May 2020 19:30:00 +010
       
  • 3D Zonation model of primary haloes and geochemical prospecting pattern of
           Aliabad Cu-Mo ...

    • Abstract: Most of hydrothermal ore deposits are controlled by geological structures and they are often a product of multistage hydrothermal activities, as a result, primary alteration haloes usually overlap in the vertical direction. By distinguishing the hydrothermal stages associated with ore-forming processes, one can determine the timings of hydrothermal activities and use the results as a method to identify blind mineralization. In order to explore probable blind mineralized zones of the Aliabad deposit, it is necessary to evaluate the element concentrations towards depth or margins of the deposit. Modelling primary geochemical haloes could be useful in this stage. The Aliabad porphyry Cu-Mo deposit, located in the southern segment of the Central Iran and adjacent to the northern border of the Urmia-Dokhtar volcanic belt and east of Dehshir fault. Ore bodies at the Aliabad deposit are primarily controlled by structural features, which provide an opportunity to investigate the zonality in primary halos in this copper-molybdenum porphyry deposit. The primary geochemical characteristics of the mineral deposit were studied based on geochemical analysis of 1559 core samples from 24 drill holes. The formation of the primary geochemical haloes, which joins the ore body up to the surface, can be associated with hydrothermal fluid diffusion through fracture (fissures) zone developed in the rocks of the folding axis in the mining area. Along the vertical direction, the concentrations of Cu, Ag and Fe shows an increasing trend from surface to the ore body, at all boreholes; while the concentration of Pb, Mn and Bi are decreased with depth at the same environment. A detailed zonality sequence of indicator elements is obtained using the variability index of these elements: Pb → (Bi, Mn, Mo) → Cr → Ni → (Sb, V, Zn) → (Ag, Co, Cu, Fe, S) → P. According to this zonality, indexes such as Vz4=Pb×Mn/Cu×Ag and Vz5=Pb×Mn/Cu×Ag×Co can be constructed and considered as a significant criterion for predicting the Cu potential at a particular depth. Studying the distribution of the zoning indexes at different levels revealed high values of proposed indexes in the northwest and south of the area. It can be concluded that copper mineralization will continue to deeper and unexplored parts of the deposit at northwest of the study area. Consequently, it is suggested that further investigations concentrate on geophysical operations and it is highly recommended to drill additional boreholes at these areas. It is noteworthy that new drillings of the north western part must continue deeper than current boreholes (>150 m); because geochemical zonality indexes are extended to deeper parts. This extension is not observed for the southern part, so, additional drillings at the southern part can be shallower than 150 m.
      PubDate: Wed, 19 Feb 2020 20:30:00 +010
       
 
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