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21.
Proposed algorithm for optimization of directional additional exploratory drill holes and computer coding 总被引：2，自引：1，他引：1
Block model estimated based on the drill hole information gathered during exploration stage is not appropriate for short- and medium-term mine planning. Additional information prior to mining is required for various purposes, that the source of this information is drill holes. In most situations, reducing the overall uncertainty on the estimation is the major objective of additional drilling and collecting samples from them. The topic of selecting the optimum location for additional exploratory drill holes has been of interest to mining engineers and geostatisticians in the second half of last century, but all of them are not able to optimize directional drill holes because they are based on the 2D space and do not consider the 3D extension of drill holes and block model. This study introduces a methodology to optimize the dip and location of additional exploratory drill holes based on the defined objective function with considering 3D extension of ore body and drill holes. Direct search simulated annealing used that is efficient and robust method for solving the nonlinear unconstrained global optimization problems. This method is very useful in the case that drilling the drill holes with different dips has been obligated due to topography condition and ore body situation. A case study in gold resource illustrates the method. 相似文献
22.
Beyranvand Azar Azizi Ghasem Alizadeh-Choobari Omid Darvishi Boloorani Ali 《Natural Hazards》2019,98(1):229-249
Large near-field tsunamis pose a significant threat to the Canadian West Coast due to its proximity to the circum-Pacific belt where a significant tsunami-inducing earthquake event from the Cascadia subduction zone is expected. This study investigated the risks associated with such an event in terms of pedestrian evacuation needs and plans for the Town of Tofino, a small community located on the West Coast of Vancouver Island. The population-at-risk within the hazard zone and its ability to evacuate to safety is evaluated using anisotropic path-distance modelling. Mitigation measures, such as vertical evacuation buildings, are quantitatively evaluated. Site-specific inundation modelling was not performed as part of this study; tsunami hazard and safe zones were computed using a range of run-ups varying between 3 and 25 m. It was established that up to 80% of the population is within the maximum hazard zone considered. This evacuation modelling exercise indicates that a maximum of 13% of the population would have insufficient time to reach safety when using a mobility-impaired ambulatory speed. The use of three vertical evacuation buildings can reduce the risk of losing population in this category by 99%. Although some conservative assumptions were used (vertical datum at higher high water, reductions in safe zones by generalization process and mobility-impaired evacuation speeds), the evacuation potential is likely overestimated due to the coarseness of the topographic data used in the evacuation modelling and from an overestimated first wave arrival time. This is the first Canadian study which used anisotropic evacuation modelling to evaluate the vulnerability of a Canadian community to tsunami inundation.
相似文献23.
H. Hosseini Shekarabi A. H. Javid P. Aberoomand Azar A. H. Hasani 《International Journal of Environmental Science and Technology》2017,14(4):803-812
The goal of this study is examination of the mixture between adsorption and permeation process for removing chromium (VI) from the water. Two types of supported membranes are developed: The first one which was made by sol–gel method is called nanoporous and the second one which was made by electrospinning is called nanofiber. The sorption capacity of nanoporous and nanofiber is examined in single batch experiments at various pH values, and it is found that maximum chromium removal is observed for both nanoporous and nanofiber at pH 3.5. Adsorption studies illustrated that the Cr(VI) adsorption onto alumina nanoporous and nanofiber is affected by changes in pH, contact time, dosage of adsorbent, concentration of chromium and solution volume. Langmuir and Freundlich isotherms can be used to explain the adsorption equilibria of Cr(VI) onto alumina nanoporous and nanofiber. It was found that balance adsorption data adequate Langmuir isotherm more than Freundlich model. Adsorption kinetics was found to be fitted to pseudo-second order and Weber and Morris model. The output of multiple linear regressions was run for the second-order response surface model implied that the linear agents of pH, sorbent dosage and Cr(VI) concentration are more significant factors. Manufacturing electrospun alumina nanofiber and sol–gel nanoporous with these cheap materials, renewable and fast methods are so important although the removal percentage is significant. 相似文献
24.
Khosrow Maroufi Naghadehi Ardeshir Hezarkhani Jamal Honarpazhouh Kumars Seifpanahi Shabani 《Arabian Journal of Geosciences》2014,7(8):3227-3241
The Taknar Zone is located at the northern margin of the eastern Iranian continental microplate, and it is host to the Taknar massive sulfide deposit. This study was conducted to find new exploration targets. We used multiple data sources (e.g., litho-geochemical and magnetic surveys) to produce more effective predictive maps. Principal component analysis and hierarchical cluster analysis methods were used to organize the new information into favorability maps and to determine multi-element correlations. We then employed fuzzy logic modeling to create favorability maps from geochemical and magnetic data. A concentration–area multifractal method was used to evaluate the final integrated favorability map for massive sulfide exploration. Our new map identifies previously unexploited sites in the eastern part of the study area, near the boundary of the Taknar formation, with intrusive and subvolcanic rocks, with potential for mineral exploration. The newly defined targets are attractive because old mined ore bodies are also identified in the favorability map. 相似文献
25.
This article presents new neural network (NN) architecture to improve its ability for grade estimation. The main aim of this
study is to use a specific NN which has a simpler architecture and consequently achieve a better solution. Most of the commonly
used NNs have a fully established connection among their nodes, which necessitates a multivariable objective function to
be optimized. Therefore, the more the number of variables in the objective function, the more the complexity of the NN. This
leads the NN to trap in local minima. In this study, a new NN, in which the connections based on the final performance are
eliminated, is used. Toward this aim, several network architectures were tested, and finally a network which yielded the minimum
error was selected. This selected network has low complexity and connection among nodes which help the learning algorithm
to converge rapidly and more accurately. Furthermore, this network has this ability to deal with the small number of data
sets. For testing and evaluating this new method, a case study of an iron deposit was performed. Also, to compare the obtained
results, some common techniques for grade estimation, e.g., geostatistics and multilayer perceptron (MLP) were used. According
to the obtained results, this new NN architecture shows a better performance for grade estimation. 相似文献
26.
Kaveh Pazand Ardeshir Hezarkhani Mohammad Ataei Yousef Ghanbari 《Chemie der Erde / Geochemistry》2011,71(4):397-402
This research is based on the application of stream sediments to mineral exploration. Identifying the geochemical anomalies from background is a fundamental task in exploration geochemistry. This paper applied the element concentration–area (C–A) model, to separating the geochemical anomalies from background based on a fractal approach and for the compilation of geochemical mapping from stream sediment samples (n = 620) of the Ahar region (Iran), where some Cu mineralization occurs. Comparisons of the known copper occurrences against the anomalous area created using thresholds from C–A method illustrate these hits. All of known Cu mineralizations and moreover defines two extra Cu anomaly districts. Additional sampling (n = 186) around new Cu anomaly confirms this anomaly within the district. 相似文献
27.
The Sonajil intrusive is located about 60 km southeast of Ahar, in Azarbaijan province in northwestern Iran, and is intruded into by andesitic trachytic Eocene pyroclastics and agglomerate. To the center, the stock is hydrothermally altered, that contains sub-economic copper mineralization. The 1,248 cells with 100?×?100 m grid were sampled, and measurement of elements by ICP-MS method and major oxides included by X-ray fluorescence method was performed. After statistical interpretations, geochemical anomalies and indices alteration (sericitization, alkali, Spitz–Darling, chloritization, Hashimoto, Hashiguchi) were calculated, and their map distribution was prepared. Based on these maps and other interpretations of data, our study indicated that despite the anomaly of copper and other elements such as gold, molybdenum, lead, arsenic and antimony of not being quite consistent, almost all of them are within the alteration zones. 相似文献
28.
Christian Azar Kristian Lindgren Michael Obersteiner Keywan Riahi Detlef P. van Vuuren K. Michel G. J. den Elzen Kenneth M?llersten Eric D. Larson 《Climatic change》2010,100(1):195-202
The United Nations Framework Convention on Climate Change (UNFCCC 1992) calls for stabilization of atmospheric greenhouse gas (GHG) concentrations at a level that would prevent dangerous anthropogenic
interference with the climate system. We use three global energy system models to investigate the technological and economic
attainability of meeting CO2 concentration targets below current levels. Our scenario studies reveal that while energy portfolios from a broad range of
energy technologies are needed to attain low concentrations, negative emission technologies—e.g., biomass energy with carbon
capture and storage (BECCS)—significantly enhances the possibility to meet low concentration targets (at around 350 ppm CO2). 相似文献
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