The Experts below are selected from a list of 11367 Experts worldwide ranked by ideXlab platform
Roussos Dimitrakopoulos - One of the best experts on this subject based on the ideXlab platform.
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optimized Open Pit mine design pushbacks and the gap problem a review
Journal of Mining Science, 2014Co-Authors: Conor Meagher, Roussos Dimitrakopoulos, David AvisAbstract:Existing methods of pushback (phase) design are reviewed in the context of “gap” problems, a term used to describe inconsistent sizes between successive pushbacks. Such gap problems lead to suboptimal Open Pit Mining designs in terms of maximizing net present value. Methods such as the Lerchs-Grossman algorithm, network flow techniques, the fundamental tree algorithm, and Seymour’s parameterized Pit algorithm are examined to see how they can be used to produce pushback designs and how they address gap issues. Areas of current and future research on producing pushbacks with a constrained size to help eliminate gap problems are discussed. A framework for incorporating discounting at the time of pushback design is proposed, which can lead to mine designs with increased NPV.
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grade control based on economic ore waste classification functions and stochastic simulations examples comparisons and applications
Mining Technology, 2014Co-Authors: Roussos Dimitrakopoulos, M GodoyAbstract:AbstractGrade control and ore/waste delineation in Open Pit Mining operations was traditionally based on the comparison of estimated grades with an economic cutoff. In the 1990s, an alternative approach to ore selection was applied and established, taking into account financial indicators through the so-called economic classification functions in combination with grade uncertainty assessment. Grade uncertainty is assessed using multiple grade realisations from geostatistical or stochastic simulations. Ore/waste selection integrates and is supported by the evaluation of economic consequences of sending a block of mined material to a processing facility or to the waste dump, and the related asymmetric financial implications.The benefits and practical implications of this efficient alternative framework are best illustrated by comparing the performance of three economic functions when combined with three commonly used stochastic simulation methods under different conditions. The latter conditions include a s...
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a heuristic approach to stochastic cutoff grade optimization for Open Pit Mining complexes with multiple processing streams
Resources Policy, 2013Co-Authors: Mohammad Waqar Ali Asad, Roussos DimitrakopoulosAbstract:Abstract Cutoff grade specifies the available supply of metallic ore from an Open Pit mine to the multiple processing streams of an Open Pit Mining complex. An optimal cutoff grade strategy maximizes the net present value (NPV) of an Open Pit Mining operation subject to the Mining, processing, and marketing/refining capacity constraints. Even though, the quantities of material flowing from the mine to the market are influenced by the expected variation in the available metal content or inherent uncertainty in the supply of ore, the majority of cutoff grade optimization models not only disregard this aspect and may lead to unrealistic cash flows, but also they are limited in application to an Open Pit Mining operation with single processing facility. The model proposed herein determines the optimal cutoff grade policy based on a stochastic framework that accounts for uncertainty in supply of ore to the multiple ore processing streams. An application on a large-scale Open Pit Mining operation develops a unique cutoff grade policy along with a portfolio of Mining, processing, and marketing/refining rates. Owing to the geological uncertainty, the approach addresses risk by showing a difference of 14% between the minimum and maximum production rates, cash flows and NPV.
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production scheduling with uncertain supply a new solution to the Open Pit Mining problem
Optimization and Engineering, 2013Co-Authors: Salih Ramazan, Roussos DimitrakopoulosAbstract:The annual production scheduling of Open Pit mines determines an optimal sequence for annually extracting the mineralized material from the ground. The objective of the optimization process is usually to maximize the total Net Present Value (NPV) of the operation. Production scheduling is typically a Mixed Integer Programming (MIP) type problem containing uncertainty in the geologic input data and economic parameters involved. Major uncertainty affecting optimization is uncertainty in the mineralized materials (resource) available in the ground which constitutes an uncertain supply for mine production scheduling.
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stope design and geological uncertainty quantification of risk in conventional designs and a probabilistic alternative
Journal of Mining Science, 2009Co-Authors: Roussos Dimitrakopoulos, Nikki GriecoAbstract:This paper adopts risk-based concepts developed in Open Pit Mining to the underground stoping environment and shows examples using data from Kidd Creek Mine, Ontario, Canada. Risk is quantified in terms of the uncertainty a conventional stope design has in expected: contained ore tones, grade and economic potential. In addition, a new probabilistic mathematical formulation optimizing the size, location and number of stopes in the presence of grade uncertainty is outlined and applied, to demonstrate the advantages of a user-defined level of acceptable risk.
Heyer Gerhard - One of the best experts on this subject based on the ideXlab platform.
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Mining Legacy Issues in Open Pit Mining Sites: Innovation & Support of Renaturalization and Land Utilization
'Association for Computational Linguistics (ACL)', 2021Co-Authors: Schröder Christopher, Bürgl Kim, Annanias Yves, Niekler Andreas, Müller Lydia, Wiegreffe Daniel, Bender Christian, Mengs Christoph, Scheuermann Gerik, Heyer GerhardAbstract:Open Pit mines left many regions worldwide inhosPitable or uninhabitable. To put these regions back into use, entire stretches of land must be renaturalized. For the sustainable subsequent use or transfer to a new primary use, many contaminated sites and soil information have to be permanently managed. In most cases, this information is available in the form of expert reports in unstructured data collections or file folders, which in the best case are digitized. Due to size and complexity of the data, it is difficult for a single person to have an overview of this data in order to be able to make reliable statements. This is one of the most important obstacles to the rapid transfer of these areas to after-use. An information-based approach to this issue supports fulfilling several Sustainable Development Goals regarding environment issues, health and climate action. We use a stack of Optical Character Recognition, Text Classification, Active Learning and Geographic Information System Visualization to effectively mine and visualize this information. Subsequently, we link the extracted information to geographic coordinates and visualize them using a Geographic Information System. Active Learning plays a vital role because our dataset provides no training data. In total, we process nine categories and actively learn their representation in our dataset. We evaluate the OCR, Active Learning and Text Classification separately to report the performance of the system. Active Learning and text classification results are twofold: Whereas our categories about restrictions work sufficient ($>$.85 F1), the seven topic-oriented categories were complicated for human coders and hence the results achieved mediocre evaluation scores ($
Hannu Rintamaki - One of the best experts on this subject based on the ideXlab platform.
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thermal comfort sustained by cold protective clothing in arctic Open Pit Mining a thermal manikin and questionnaire study
Industrial Health, 2017Co-Authors: Kirsi Jussila, Sirkka Rissanen, Anna Aminoff, Jens Wahlstrom, Arild Vaktskjold, Ljudmila Talykova, Jouko Remes, Satu Manttari, Hannu RintamakiAbstract:Workers in the Arctic Open-Pit mines are exposed to harsh weather conditions. Employers are required to provide protective clothing for workers. This can be the outer layer, but sometimes also inne ...
Schröder Christopher - One of the best experts on this subject based on the ideXlab platform.
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Mining Legacy Issues in Open Pit Mining Sites: Innovation & Support of Renaturalization and Land Utilization
'Association for Computational Linguistics (ACL)', 2021Co-Authors: Schröder Christopher, Bürgl Kim, Annanias Yves, Niekler Andreas, Müller Lydia, Wiegreffe Daniel, Bender Christian, Mengs Christoph, Scheuermann Gerik, Heyer GerhardAbstract:Open Pit mines left many regions worldwide inhosPitable or uninhabitable. To put these regions back into use, entire stretches of land must be renaturalized. For the sustainable subsequent use or transfer to a new primary use, many contaminated sites and soil information have to be permanently managed. In most cases, this information is available in the form of expert reports in unstructured data collections or file folders, which in the best case are digitized. Due to size and complexity of the data, it is difficult for a single person to have an overview of this data in order to be able to make reliable statements. This is one of the most important obstacles to the rapid transfer of these areas to after-use. An information-based approach to this issue supports fulfilling several Sustainable Development Goals regarding environment issues, health and climate action. We use a stack of Optical Character Recognition, Text Classification, Active Learning and Geographic Information System Visualization to effectively mine and visualize this information. Subsequently, we link the extracted information to geographic coordinates and visualize them using a Geographic Information System. Active Learning plays a vital role because our dataset provides no training data. In total, we process nine categories and actively learn their representation in our dataset. We evaluate the OCR, Active Learning and Text Classification separately to report the performance of the system. Active Learning and text classification results are twofold: Whereas our categories about restrictions work sufficient ($>$.85 F1), the seven topic-oriented categories were complicated for human coders and hence the results achieved mediocre evaluation scores ($
Kirsi Jussila - One of the best experts on this subject based on the ideXlab platform.
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thermal comfort sustained by cold protective clothing in arctic Open Pit Mining a thermal manikin and questionnaire study
Industrial Health, 2017Co-Authors: Kirsi Jussila, Sirkka Rissanen, Anna Aminoff, Jens Wahlstrom, Arild Vaktskjold, Ljudmila Talykova, Jouko Remes, Satu Manttari, Hannu RintamakiAbstract:Workers in the Arctic Open-Pit mines are exposed to harsh weather conditions. Employers are required to provide protective clothing for workers. This can be the outer layer, but sometimes also inne ...
