排序方式： 共有73条查询结果，搜索用时 31 毫秒
51.
A new approach for the geological risk evaluation of coal resources through a geostatistical simulation 总被引：1，自引：1，他引：0
Estimations of mineral resources and ore reserves have been recently widely used by mining engineers and investors. The classification framework based on the prepared code by the Joint Ore Reserves Committee of The Australasian Institute of Mining and Metallurgy, Australian Institute of Geoscientists and Minerals Council of Australia (JORC code), which is one of the international standards for mineral resource and ore reserve reporting, provides a template system that conforms to international society requirements. Recent research has shown that an existing fault risk can affect the mineral resource and ore reserve estimation. According to this research, the faulted area that is involved in the effect on the estimated region is so extensive that it is not distinguishable. In this research, a new method called FGT (F for fault, G for grade and T for thickness) is introduced and presented for the estimation of mineral resources. The proposed method can provide an error map of a particular aspect of the combination of coal accumulation (G), fault risk (F) and thickness (T), and its output would categorise the mineral resources. This method was implemented in the Parvadeh Ш coal deposit, which is located in the eastern portion of Central Iran. The deposit contains five seams named B1, B2, C1, C2 and D; of these, C1 was selected as the most important seam in the exploratory grid analysis. Thus, C1 alone can reflect the properties of the Parvadeh Ш deposit. In this study, we compared the conventional method and the FGT method. This comparison indicated that the areas that should be rejected from the region in the FGT method are less and more distinguishable than those determined with the conventional method. Therefore, the inferred resources can be completely differentiated from the indicated and measured resources with a high resolution. The conventional method cannot distinguish between these three categories at this level of resolution. Therefore, the FGT approach has high precision in classifying the coal resource compared to the conventional method. 相似文献
52.
Fault detection in 3D by sequential Gaussian simulation of Rock Quality Designation (RQD) 总被引：1，自引：0，他引：1
Gazestan phosphate ore deposit (Central Iran) is an apatite deposit which is instrumental in selecting the method of excavation. The position of fault systems and the condition of rock quality also play a role in the method used for mineral resources and ore reserves estimation. Conversely, the Rock Quality Designation (RQD) is a parameter that provides a quantitative judgment of rock mass quality obtained from drill cores. This factor can be applied to detect the fractured zones which occur due to fault systems. Additionally, the faulted areas can be determined by surface geological map and a few by core drilling. Some of the faulted areas are not distinguishable in the surface and are covered by soils, especially within 3D modeling and visualization. In this study, an attempt has been made to establish a relationship between the RQD percentages which were geostatistically simulated and faulted areas through the region. In comparison, the results showed that low RQD domains (RQD <20 %) can be interpreted as fault zones; high RQD domains (RQD >50 %) correspond to less fractured areas, and the contact between high and low RQD domain is gradual. Therefore, this categorization of RQD domains can be incorporated to detect the faulted zones in 3D models for mine design. Based on the categorization, the uncertainty within the area was calculated to introduce two new core drilling points for the completion of this phase of exploratory grid from the fault structural viewpoint, in order to have a proper model of ore reserve to estimate. It was concluded that this procedure can be utilized for conceptual comprehension of fault trends in 3D modeling for the method selection of excavation and complete the estimation procedure phase. 相似文献
53.
Abedi Maysam Asghari Omid Norouzi Gholam-Hossain 《Arabian Journal of Geosciences》2015,8(4):2179-2189
Arabian Journal of Geosciences - This paper describes a general framework of incorporating magnetic data as prior information in the modeling of an iron deposit based on sparse drilling boreholes.... 相似文献
54.
Omid?Hamidi Leili?Tapak Hamed?Abbasi Zohreh?MaryanajiEmail author 《Theoretical and Applied Climatology》2018,134(3-4):769-776
We have conducted a case study to investigate the performance of support vector machine, multivariate adaptive regression splines, and random forest time series methods in snowfall modeling. These models were applied to a data set of monthly snowfall collected during six cold months at Hamadan Airport sample station located in the Zagros Mountain Range in Iran. We considered monthly data of snowfall from 1981 to 2008 during the period from October/November to April/May as the training set and the data from 2009 to 2015 as the testing set. The root mean square errors (RMSE), mean absolute errors (MAE), determination coefficient (R 2), coefficient of efficiency (E%), and intra-class correlation coefficient (ICC) statistics were used as evaluation criteria. Our results indicated that the random forest time series model outperformed the support vector machine and multivariate adaptive regression splines models in predicting monthly snowfall in terms of several criteria. The RMSE, MAE, R 2, E, and ICC for the testing set were 7.84, 5.52, 0.92, 0.89, and 0.93, respectively. The overall results indicated that the random forest time series model could be successfully used to estimate monthly snowfall values. Moreover, the support vector machine model showed substantial performance as well, suggesting it may also be applied to forecast snowfall in this area. 相似文献
55.
56.
Azin Movahedi M. R. Kavianpour Omid Aminoroayaie Yamini 《Environmental Earth Sciences》2018,77(8):320
Flip buckets are often used at the end of chute spillways to dissipate energy and direct flow to submergence plunge pool and especially in large dams. Flip buckets with central deviation also are a specific and new design of these buckets that have a transverse slope and are mixed in plan with a curvature. In this paper, the experimental and numerical simulation study of sediment scouring in such flip bucket has been targeted. Extensive experimental data are obtained from physical model studies conducted at Water Research Institute, Iran. The flow field with various flood discharges in a range of Froude numbers (Fr?=?\(V/\sqrt {gh}\): 3.5–7.5) in Flow3D model was compared to experimental results obtained from a similar model. Analyzing the simulated models in the Flow3D model and comparing the results with the experimental model, the hydraulic parameters of the pressure, velocity and depth of flow are determined. Considering the accuracy of the numerical model in simulating bed scouring, this model can be used for similar cases in large dams. The results of the simulation model compare well with the experimental results in parameters of the maximum scour depth, profile scouring and the ridge height which accumulates around downstream of the scour hole. This investigation improves the understanding of bed topography effects of downstream dams in high-velocity jet impact based on experimental observations and simulation analysis. 相似文献
57.
The study of human mobility has gained much attention in recent years. To date, various models have been developed to predict human mobility patterns for intra- and/or inter-city cases. These models incorporate the populations as proxy variables in the place of real variables which cannot be observed easily. However, inaccuracies in predicting human mobility within cities are usually encountered. One source of inaccuracies in intra-city scenarios arises from the fact that cities’ populations are influenced by people from other areas. Therefore, population cannot be regarded as a good proxy variable for movement modeling. The objectives of this article are to introduce new proxy variables for use in current models for predicting human mobility patterns within cities, and to evaluate the accuracy of the predictions. In this study, we have introduced new proxy variables, namely, venues and check-ins, extracted from location-based social networks (LBSNs). In order to evaluate the models, we have compared our results with empirical data obtained from taxi vehicles, based on trip distances and destination population distributions. The Sørensen similarity index (SSI) and R-squared measures were also used to compare the performances of models using each variable. The results show that all models with LBSN variables can capture real human movements better within Manhattan, New York City. Our analytical results indicated that the predicted trips using LBSN data are more similar to the real trips, on average, by about 20% based on the SSI. Moreover, the R-squared measures obtained from regression analyses were enhanced significantly. 相似文献
58.
Talesh Hosseini Sajjad Asghari Omid Benndorf Jörg Emery Xavier 《Mathematical Geosciences》2023,55(4):541-562
One main problem in the modeling of mineral deposits is to design a block model that divides the deposit into homogeneous subdomains. The spatial uncertainty in the geological boundaries becomes a critical factor prior to the modeling of the ore properties. For this reason, reducing the uncertainty of geological models leads to an improved mineral resource evaluation. This research work addresses the problem of updating the geological models by using actual online-sensor measurement data. A novel algorithm is provided, which integrates the discrete wavelet transform to the Ensemble Kalman Filter for assimilating online-sensor production data into geological models. The geological realizations in each time step are transformed to frequency coefficients and, after each assimilation step, the updated realizations are back-transformed to the original categorical distribution. Furthermore, a reconciliation process is performed to compare the online-sensor data derived from the production blocks and the updated realizations in each time step. The algorithm is illustrated through an application to the Golgohar iron deposit located in SW of Sirjan, Iran, and proves to reproduce the statistical parameters and connectivity values of the primary geological realizations.
相似文献59.
Nalivan Omid Asadi Badehian Ziaedin Sadeghinia Majid Soltani Adel Islami Iman Boustan Ali 《Natural Hazards》2022,111(2):1661-1684
Natural Hazards - In an effort to improve the previous gully susceptibility assessments in Iran, we attempted to conglomerate the notions of susceptibility, vulnerability, and exposure associated... 相似文献
60.
Lateral deformation of liquefiable soil is a cause of much damage during earthquakes, reportedly more than other forms of liquefaction-induced ground failures. Researchers have presented studies in which the liquefied soil is considered as viscous fluid. In this manner, the liquefied soil behaves as non-Newtonian fluid, whose viscosity decreases as the shear strain rate increases. The current study incorporates computational fluid dynamics to propose a simplified dynamic analysis for the liquefaction-induced lateral deformation of earth slopes. The numerical procedure involves a quasi-linear elastic model for small to moderate strains and a Bingham fluid model for large strain states during liquefaction. An iterative procedure is considered to estimate the strain-compatible shear stiffness of soil. The post-liquefaction residual strength of soil is considered as the initial Bingham viscosity. Performance of the numerical procedure is examined by using the results of centrifuge model and shaking table tests together with some field observations of lateral ground deformation. The results demonstrate that the proposed procedure predicts the time history of lateral ground deformation with a reasonable degree of precision. 相似文献